Copper Development Association

Copper – The Vital Metal

CDA Publication 121, 1998 Copper – The Vital Metal CDA Publication 121 April 1998

(This book replaces CDA Book 1 ‘Introduction to Copper’, 1988)

Members as at 1st January 1998 ASARCO Inc Boliden MKM Ltd Thomas Bolton Ltd The British Non-Ferrous Metals Federation Chile Copper Ltd Gecamines IMI plc Inco Europe Ltd Noranda Sales Corporation of Canada Ltd Rio Tinto London Ltd Southern Peru Copper Corporation

Acknowledgements This publication is financed by the members of Copper Development Association, European Copper Institute, British Non-Ferrous Metals Federation and Aalco. CDA is glad to acknowledge with thanks the provision of illustrations where noted.

Copper Development Association Copper Development Association is a non-trading organisation sponsored by the copper producers and fabricators to encourage the use of copper and copper alloys and to promote their correct and efficient application. Its services, which include the provision of technical advice and information, are available to those interested in the utilisation of copper in all its aspects. The Association also provides a link between research and user industries and maintains close contact with other copper development associations throughout the world.

Website: www.cda.org.uk Email: [email protected]

Copyright: All information in this document is the copyright of Copper Development Association Disclaimer: Whilst this document has been prepared with care, Copper Development Association can give no warranty regarding the contents and shall not be liable for any direct, indirect or consequential loss arising out of its use Contents Contents...... 3 Overview ...... 5 Section 1 - Attributes and Applications ...... 7 The Vital Modern Metal...... 7 Where would we be without copper? ...... 7 Copper and copper alloys are essential for:...... 7 Basic Properties of Coppers...... 10 Applications of Copper and Copper Alloys ...... 11 Features and Benefits of Copper and Copper Alloys ...... 16 Typical Applications of Copper and Copper Alloys ...... 16 Application Examples ...... 23 Section 2 – Availability...... 27 Forms available...... 27 Wrought Forms ...... 28 Castings...... 28 Buying copper and copper alloys...... 31 Manufacturers ...... 31 Foundries...... 32 Stockists ...... 32 Primary Copper Reserves ...... 32 Recycling Copper and Copper Alloys ...... 33 Sustainability of Copper Supplies...... 35 Section 3 - Copper in Health and Environment...... 36 Copper and Health...... 36 Copper in the Environment...... 37 Copper in Farming...... 37 Section 4 - Copper and its Alloys...... 38 Coppers...... 38 Copper alloys...... 38 Copper and High Conductivity Copper Alloys...... 39 Bronzes and Phosphor Bronzes...... 41 Aluminium Bronzes (Copper-Aluminium Alloys) ...... 42 Brasses ...... 42 Gunmetals ...... 45 Nickel Silvers...... 45 Copper-Nickel alloys...... 46 Copper-Nickel-Silicon ...... 47 Copper- Beryllium Alloys ...... 48 Copper in other Metals...... 48 Copper Compounds...... 49 Section 5 - Making Components...... 50 Fabrication, Joining and Finishing...... 50 Fabrication ...... 50 Hot Working ...... 50 Cold Working...... 50 Machining ...... 51 Joining...... 52 Finishing...... 52

3 Section 6 - Mining and Extraction ...... 53 Mining of ores and copper extraction...... 53 Copper and Mineral Ores...... 53 Extraction...... 56 Section 7 - Standards, Compositions and Properties...... 58 A Variety of Standards...... 58 The New BS EN Standards ...... 58 Withdrawal of old standards ...... 58 Numbers and Titles of Standards ...... 60 Product Forms...... 60 Material Designations ...... 60 Material Condition (Temper)Designations ...... 61 Castings...... 62 Examples...... 62 Typical Properties...... 62 Section 8 - Historical ...... 63 Copper through the ages...... 63 The Copper Age...... 63 The Bronze age ...... 63 Middle Ages and beyond ...... 64 Brass...... 65 The Outlook for Copper ...... 67 Section 9 - Glossary, Reference and Further Information...... 70 Glossary...... 70 References and Further information ...... 75 Internet...... 75 References...... 75

Tables Table 1 – Some copper and copper alloy attributes and applications...... 11 Table 2 – Properties not considered ...... 14 Table 3 – Descriptions of terms for wrought products ...... 28 Table 4 – Minerals of Copper ...... 54 Table 5 - BS EN Standards for Copper and Copper Alloys ...... 59 Table 6 - Cuprobraze vs brazed aluminium for radiators ...... 67 Table 7 - Comparison of lifetime costs of typical roofing materials ...... 69 Table 8 – Abbreviations for chemical elements used as alloying additions or found as impurities...... 74

Figures Figure 1 – Reasons for using copper ...... 16 Figure 2 – Production routes for the manufacture of copper and brass castings, semi-finished and finished products ...... 27 Figure 3 – Recycling of copper ...... 34 Figure 4 - Some of the effects of alloying additions on the properties of copper...... 39 Figure 5 – Comparison of machinabilities of common engineering metals...... 52 Figure 6 – Production of copper in each continent...... 55 Figure 7 – Flowsheet for primary copper production...... 57

4 Overview Copper and Copper Alloys Introduction, Applications, Compositions and Properties

Section 1 - Attributes and Applications

Statue of Liberty This well known statue has long lasting copper cladding which withstands the harsh marine environment of New York. (International Copper Association (ICA)

Section 2 - Availability

Stocks of free-machining brass rod. (Currie and Warner)

Section 3 - Copper in Health and Environment Healthy pig thriving on a well balanced diet including sufficient copper. (Vin Callcut)

Section 4 - Copper and its Alloys

Coins Special copper alloys are used for the manufacture of most coins. The British £1 coin is basically an 80/20 brass, the ‘silver’ coins are made from copper-nickel alloys and coinage bronze, with low tin content, is used for low denomination coins. (Vin Callcut)

5 Section 5 - Fabrication, Joining and Finishing

Copper-nickel water box for shipboard seawater cooling system. (James Robertson Ltd)

Section 6 - Mining and Extraction

Bingham Canyon copper mine (Vin Callcut)

Section 7 - Standards, Compositions and Properties

Section 8 - Historical Pulley wheels from the ‘Mary Rose’

Section 9 Glossary, Index, References and Further Information

6 Section 1 - Attributes and Applications

The Vital Modern Metal

Where would we be without copper? Copper and copper alloys meet the challenges of modern life in many ways. Often seen in plumbing systems and good quality roofing, they are also frequently unseen providing essential services inside equipment in houses, offices, commercial and industrial buildings. They are amongst the most necessary materials needed to provide the means to keep home, commerce and industry running.

Copper and copper alloys are essential for: • Power cables for home, commerce and industry

Submarine power cable (Pirelli plc) This is one of the cables which links Britain and France across the English Channel, providing each country with up to 2000MW of power from the other’s national supply.

• Message cables for telephones, fax machines, computer networks and cable television.

Modern Telephone (Vin Callcut) Printed circuit boards, connectors, cables and coils all depend on high conductivity copper.

7 • Winding wires for motors, transformers and other electromagnetic coils.

Transformers (GEC Transformers) Transformers rely on copper to ensure low energy loss and many years without maintenance.

• Electrical contacts, terminals, connectors, plugs and sockets.

A variety of electrical connectors of good reliability and long service life made from rolled copper alloy strip.

8 • Plumbing tube for water supplies, central heating and fire safety sprinklers.

Globe Theatre sprinkler pipework When space is limited, the ease with which copper tube can be joined is a distinct advantage. Good resistance to corrosion and immunity from degradation leads to a long, reliable, maintenance-free installation life ensuring fire safety in this thatched building.

• Pumps, tubes and fittings for marine, offshore and chemical engineering.

Marine self-priming pump (Gilbert Gilkes and Gordon Ltd) This cross section reveals a variety of copper alloy castings within this component.

• Durable architectural items such as roofs, flashings, balustrades, handrails and functional, decorative items.

9 Copper roof of the Usher Hall, Edinburgh (Vin Callcut)

• Essential trace element effects for the survival and growth of plant, animal and human life.

Maize (National Agricultural Research Station, McKechnie) Maize samples grown with and without trace element, copper Copper is probably the most versatile metal in common use.

Basic Properties of Coppers Copper possesses the highest conductivity of any of the commercial metals. Hold a piece of copper and it will feel cold, an indication of how quickly hand heat can be conducted away. Each time you press a switch to light a room, think of the high electrical conductivity of the copper in the circuit that makes that simple operation possible. We take for granted the electrical power and also the metal essential for its efficient arrival at our homes. Lightning conductors in copper are a familiar sight protecting tall buildings - 200 years ago a conductor was attached to St Paul's Cathedral to lead lightning strikes safely to earth for that historic landmark. Each time you turn on a water tap, think of the copper tubing that delivers the water hygenically within your home. Copper has excellent resistance to atmospheric and marine corrosion and good corrosion resistance when used in many industrial process environments. Add other elements to copper and we can get alloys that show good mechanical strength at low, ambient and elevated temperatures combined with high ductility and many other advantages. The surface lustre and warm colour of copper and copper alloys makes them beautiful to look at and this means they find widespread use in architecture. The attractive green surface patina enhances the appearance of copper roofing. Bronze sculpture may have exquisite toning or patination. Jewellery and household ornaments and fittings gleam satisfyingly. If you look no further than your domestic surroundings, you will start to appreciate the huge role played by copper in the production of useful, attractive items that enhance our lives. The word copper is used in everyday speech in the expression "a copper bottomed guarantee" as an assurance of long-term reliability. Could you imagine a world without copper?

10 Applications of Copper and Copper Alloys The following table shows some of the reasons why copper and copper alloys are vital to the major types of application that benefit from combinations of the great many attributes available.

Table 1 – Some copper and copper alloy attributes and applications

Property Industry/Type of application (Picture Reference)

Aesthetics Architecture Sculpture Jewellery Clocks Cutlery.

Reproduction carriage clock showing many brass components. (Vin Callcut) Bactericide Door furniture Agricultural crop treatments.

Brass handrails - Royal Museum of Scotland (Vin Callcut) Bearing/anti- General and heavy engineering galling properties Metal working Biofouling Aerospace resistance Internal combustion engines Boat building Offshore oil and gas platforms.

Morecambe Bay gas platform. The steel legs of the platform are clad with 90/10 copper nickel alloy sheet to protect them from corrosion, abrasion and biofouling caused by the sea. (British Gas)

11 Table 1 (continued)

Property Industry/Type of application (Picture Reference)

Corrosion Plumbing tubes and fittings resistance Roofing General and marine engineering Naval vessel and boat building Chemical engineering Industrial processes e.g. pickling, etching and distilling, Domestic plumbing Architecture Desalination Textiles Paper making.

Brass searchligh tfor demanding marine applications. Usually it is lacquered black. (Francis Searchlights) Ease of All of the above plus printing. fabrication Electrical Electrical engineering conductivity Communications Resistance welding Electronics.

Rotor for a heavy duty motor (Brush Electrical Machines Ltd)

Environmental Vital for health of crops, animals and humans. friendliness

Healthy wheat alongside other samples grown in copper-deficient soils. (ICA)

12 Table 1 (continued)

Property Industry/Type of application (Picture Reference)

Fungicide Agriculture Preservation of food and wood. Hardness Non-sparking tools Springs. Low temperature Cryogenics properties Lquid gas handling. Mechanical General engineering, strength/ductility Marine engineering Defence Aerospace.

Non-magnetic Instrumentation Geological survey equipment Mine counter-measure vessels Offshore drilling.

Non-sparking Mining tools Oxygen distribution.

Nickel-Aluminium Bronze chisels. These non-sparking tools are used in hazardous environments such as in mines and the petrochemical industry. (Delta (Manganese Bronze) Ltd) Resistance to Offshore oil and gas (subsea), hydrogen Boat/ship construction. embrittlement Strength Architectural fixings Engineering components. Springiness Electrical springs and contacts Safety pins Instrument bellows.

13 Table 1 (continued)

Property Industry/Type of application (Picture Reference)

Thermal Heat exchangers conductivity Automotive radiators Dies for plastics moulding Internal combustion engines Mining.

New design of economic, high- efficiency light weight automotive radiator(ICA) Wear resistance General and heavy engineering Shipbuilding Moulds and dies.

Adjusting nut for a rolling mill cast in high-tensile brass. (Westley Brothers plc)

Table 2 – Properties not considered Coppers and copper alloys do not suffer from the following problems: Rusting Corrosion of steel is a continuous process giving a large volume of rust that spalls off. This has a particularly bad effect underneath plating or when embedded in concrete. Degradation by sunlight or Many plastics suffer this phenomenon which results in loss of ultra-violet light properties and appearance. Attack by ozone Many plastics suffer this problem as well as the effect of ultra-violet light. Migration of plasticiser Many plastics suffer this problem. Loss of properties at slightly Many plastics lose strength rapidly above ambient temperatures. elevated temperatures

Low temperature Many plastics and other metals become brittle at low temperatures. embrittlement Rapid formation of a non- Aluminium develops a film with an insulating layer that gives high conducting oxide layer electrical resistance. Requirement for expensive Production processes for many plastics are expensive to set up. moulding tools

14 15 Features and Benefits of Copper and Copper Alloys The unique combination of properties offered by copper and its alloys results in benefits when they are used in the many industries referred to. In many instances the ideal property combination required can be met only by a copper base material. There may be no better alternative material choice - other material types such as iron base alloys (carbon, alloy and stainless steel), nickel base alloys, aluminium alloys and alloys based upon titanium do not, in very many cases, combine all the required properties or their cost may be too high. Figure 1 shows the main results of a survey of the important properties required when copper is being selected for the manufacture of components.

Figure 1 – Reasons for using copper

Typical Applications of Copper and Copper Alloys

Domestic/Household Copper and copper alloys fulfil a vast number of requirements in and around the home, being both economically functional and superbly decorative. Domestic applications include electrical cables and switches, electric motors for refrigerators, freezers, vacuum cleaners and other power tools, bathroom fittings, water tanks, pipes for drinking water and central heating, plumbing fittings, door furniture, ornaments, cutlery, clocks, cooking utensils, solar panels and soldering irons, to name but a few. Copper is the usual choice for domestic plumbing tube because it is safe, reliable, durable, easy to install and easy to join with either soldered copper or screw- tightened brass fittings.

Brass mixer taps - The economic costing of these taps belies a complex design with intricate internal passages for the hot and cold water (Armitage Shanks)

16 Electrical Applications

Copper Cabling: Copper has the highest electrical conductivity of all the common metals and is used in commercial and domestic buildings to provide the energy-efficient, safe, electrical distribution systems upon which we all rely. The copper wire is strong enough for the purpose, yet fully ductile when bending to shape is needed. It does not react with modern insulation materials. It has a low contact resistance throughout its long life, giving safe terminations. It has a good creep strength, meaning that sound joints made in screwed terminals do not relax when the operating temperature is reached.

Domestic: The amount of high conductivity copper used in domestic buildings is on the increase to cope with the demands of modern living i.e. the increased number of electrical appliances in use, in particular home personal computers. Older properties often have an insufficient number of socket outlets to cope with this high demand and even new homes have inadequate provision if the Fire Brigade’s recommendation of ‘One plug-One socket’ is to be followed and so avoid the need for hazardous multi-socket adapters. If consumer demand and customer satisfaction are to be taken into account, electrical specifications of new homes must be doubled to meet safely the needs of the 21st century.

Commercial/industrial: The continuous availability of a high quality, energy efficient power supply is essential to the economy of a business. Power failures can mean loss of data and customer confidence. When designing electrical installations, either for new buildings or to upgrade existing buildings, it is vital that power quality, reliability, resilience, energy efficiency, earthing and future load growth are taken into consideration. Energy Efficiency: By selecting energy-efficient motors and larger sized copper conductors for industrial applications or heating and ventilation systems in commercial buildings, considerable savings in running costs can be made with relatively short payback periods. The reduction in power consumed by energy-efficient installations including transformers, cables, busbars and motors, leads to cost savings to users and reduced emissions to the environment from power stations. Power Quality: Modern electronic loads, such as motor controllers, and the switched mode power supplies used by personal computers, draw high levels of harmonic currents which do not cancel in the neutral of a three phase system. The common practice of using half-sized neutrals is unsound wherever harmonics are likely to be present, which nowadays means almost every commercial and industrial installation, and a good case can be made for the use of double sized neutrals. One easy solution is to use five-core copper power cable – three cores for the phases and two for the neutral. Integrating the fifth core with the cable ensures good current sharing between the neutral cores. Earthing: Where earthing must have a low impedance, there is a strong case for adding an extra copper conductor rather than relying on unreliable joints in steel armouring and conduit. Power supplies for computers and the electronic controls for most modern equipment rely on an earth leakage current to stabilise the voltage. Any breakage of earthing circuits will now result in dangerous voltages and must therefore be avoided at all costs.

17 Electrical Engineering High conductivity copper is used for electrical windings of all types of equipment to ensure reliability, compactness and energy efficiency. There are also many demanding applications that require specialised high-strength high conductivity copper alloys. Other typical applications include contacts, switches, railway electrification, communications, motor end rings and computing.

Overhead wiring for railways (Vin Callcut) Only copper has the high conductivity and wear resistance needed for 25kV high speed railway traction Separate books are available on the topics of ‘Electrical Energy Efficiency’[1], ‘Busbars’[2], ‘Earthing’[3] and ‘Electrical Design – A Good Practice Guide’[4].

General Engineering Copper and copper alloys are tailored to meet almost any foreseeable need in engineering industries ranging from hi-tech miniaturised modern requirements to the needs of heavy industry for strong, versatile materials with excellent corrosion resistance. Typical engineering applications include valves, pumps, heat exchangers, vessels, vehicle components such as radiators and valve guides, hydraulic tubing, bolting, mining wagon brakes and plastics moulding dies to name just a few.

Copper lined steel pressure vessel for heavy duty service (IMI Rycroft)

Bearings Copper alloys can be used to make many types of bearings since these need a special combination of properties.[5] Usually the alloy has a distributed hard phase that makes a good lubricant set in a matrix of softer material that supports it and conducts heat from the bearing surface. Hard alloys such as phosphor bronze and aluminium bronze are used against hardened steel shafts. Softer materials such as leaded bronzes are used when the shafts are conventional low alloy steel.

18 Precision brass bearing used in aircraft generators (MPB Corporation)

Marine Environments The excellent corrosion resistance in marine environments possessed by specially formulated copper alloys is combined with resistance to biofouling which confers a very useful advantage for desalination piping, pumps, valves, naval vessel components, boat propellers, shafts and rudders, yacht fittings, boat hulls, fish farming cages, Offshore oil and gas equipment made in copper alloys includes pumps, splash zone and subsea bolting, drill collars, piping systems, valves, deluge system sprinklers and anti-fouling collars.

Aluminium bronze propeller (Stone Manganese Marine) Aluminium bronze is the standard material to meet requirements for high strength and corrosion resistance.

Building and Construction Roofing: Copper has been used as a roofing material from as early as 27 BC. When the Pantheon in Rome was built it was roofed with copper. The suitability of the metal as a roofing material has been proved over the succeeding centuries. The essential attributes of good long- life roofing material include an attractive appearance, high corrosion resistance, minimum maintenance requirement and good economy[6]. Copper combines all of these qualities better than any other weathering material and is therefore an excellent choice for a roof covering.

19 Copper roof on the Commonwealth Institute, London, now patinated to an attractive green colour.

Putney Bridge Restaurant

New Standard Life Building, Edinburgh Architecture: As well as being ideal for roofing, copper is also used for wall cladding and is excellent as a flashing material. Besides the corrosion resistance and attractive appearance copper also acts as an algaecide and fungicide, keeping growths such as moss and lichens at a minimum. Copper and its alloys are used for many decorative features such as window frames, weather vanes, urns, finials, balustrades and shop fronts. Copper alloys, like brass, are also ideal for interior uses[7]. They make durable, good-looking handrails, stanchions, decorative panels and are suitable for heavy duty use in lift door tracks, hinges, locks and other door furniture. As door furniture, brass has the advantage of being a bactericide, reducing the transmission of infections. It is therefore popular for use in hospitals and other public buildings. Note, though, that this benefit is mostly lost if the components are lacquered. Nevertheless, they still look good and do not need such frequent polishing. For statues, bronze has been the accepted standard material for centuries. Cast with expert precision, then assembled, finished, patinated and waxed with great craftsmanship, they fittingly commemorate many fine achievements.

20 Bell founder and his bell - This intricate bronze casting represents the bellfounder’s art. (R Bracegirdle, courtesy John Taylor Bellfounders Ltd and the Bellfoundry Museum, Loughborough) Structural Components: For many years phosphor bronze securing bolts and anchor plates were standard for masonry fixings for heavy wall cladding. The application illustrates the strength and long term reliability of copper alloys. Correct choice of alloy and diameter means minimum sensitivity to fatigue, crevice corrosion and stress corrosion. More advanced applications include bearings for bridges and similar structures that must allow for expansion. Aluminium bronzes have been used successfully for many years to take the entire weight of the reinforced concrete roof structure at the Physics and Mathematics Building at the University of Aberdeen. The cast aluminium bronze feet are seated in sockets made of similar material deep set in concrete and continue to pass inspection with no problems reported.

Aluminium bronze ball and socket joints support the immense weight of the concrete arches of Aberdeen University Science Building (Vin Callcut) Copper Tube and Fittings: The properties of copper tube and fittings make them the ideal choice for pipework systems within buildings. Copper is the preferred material chosen for plumbing, heating and natural gas and fire sprinkler system pipework. Copper tube can be quickly and neatly jointed by soldering to form leak proof joints. When space is limited, the ease with which copper tube can be joined is a distinct advantage, as is the relationship between the outside diameter and the bore of the tube. The strength of copper allows the wall thickness to be kept small, so that, for the same bore size, the outside diameter of a copper tube will be smaller than a tube of other, weaker, materials. The lightness of copper tube, compared to other 21 metals, and its rigidity, makes it easier to install in confined spaces with few hangers and supports for straight pipe runs. Good resistance to corrosion and immunity from degradation leads to a long, reliable, maintenance-free installation life.

Globe Theatre roof drenchers, part of the precautions against fire

Automotive: Copper represents 6 to 9% by weight of the content of a typical car, being essential for the full wiring harness, for the windings of the alternator, the starter motor and other motors, for actuators. Copper alloys are needed for conductive spring clips, terminals and connectors. Copper alloys can be used for bearings, gears and valve guides. Small machined components can be made cheaper in brass than in steel and do not need such critical protection against corrosion.

Brake pipes in a Volvo car made of copper-nickel for long service in the corrosive environments caused by salt on roads (Vin Callcut) Defence: Defence requirements are for components made to meet the most demanding service needs. These involve fitness for purpose when made and many years of totally reliable life. This has meant the continuous evolution of materials made to the most rigorous demands on manufacturing techniques and quality control. Many new alloys have been developed and manufacturing procedures perfected for materials to meet these needs that also have made significant advances possible in non-defence applications. Original defence applications were mainly for bronzes for spears, swords and cannon. Later came the use of copper sheet cladding on ships, to prevent the attack of the Toredo worm, that had the added advantage of preventing the drag caused by marine biofouling. Brass or bronze was also used for pulley blocks such as those recovered from the wreck of 'The Mary Rose'.

22 Model of ship showing the copper cladding that was used to protect the timbers from attack by enemies such as the Toredo worm and the hampering growth of marine biofouling (Tony Rayne) Modern requirements are for high-performance, high pressure valves, pump bodies and shafts, hydraulic tubing, bolting, heat exchangers, flexible pipe systems, flanges, hose couplings, sonar equipment, bow plane control gear, steering mechanism and turret gears in tanks, aircraft undercarriage components and periscopes. Most of the vital equipment developed has similar applications in industry. Materials originally developed for naval condenser tubes are now produced in large tonnages for other marine systems, desalination plant and the chemical industry. The new use of corrosion-resistant 90/10 copper-nickel for automotive brakelines is another good example of technology transfer. The technology of alloying, casting and fabricating the high-strength, corrosion resistant aluminium bronzes was developed mainly for defence requirements. It now applies especially to the pumps, valves, fittings and pipelines used for marine seawater systems in all types of ships and offshore platforms.

Application Examples As examples, the following brief case studies give an indication of the wide variety of applications where there is a need for a property combination and cost-effectiveness found ideally in copper base materials:

Architecture

New office building for the Houses of Parliament with aluminium bronze columns and roofing structure for durability, longevity and good appearance

23 For the new office building for the Houses of Parliament in Westminster, aluminium bronze was chosen for structural roof beams. High strength combined with atmospheric corrosion resistance and outstanding aesthetic appeal mean that maintenance free structures can be produced which look attractive. The hollow columns are also used to funnel rainwater unobtrusively to the downpipes, while the chimneys are a vital part of the drafting for the air conditioning system.

Offshore oil and gas

Marinel fasteners with high strength for underwater petrochemical installations (Langley Alloys) High strength copper-nickel chosen to give the required strength and seawater corrosion resistance combined with good galling/seizure resistance, hydrogen embrittlement resistance and galvanic compatibility with adjacent stainless steel. This means that, even with high stresses involved, a "fit and forget" material selection solution has been found for this safety critical application and that trouble free continuous oil/gas production can proceed for many years.

Automotive

Electric motor under car bonnet Copper wiring is essential to all motors, actuators and harnesses in the modern car. (Vin Callcut) High conductivity copper for wiring harnesses, windings for alternators, motors and actuators, alloys for terminals, fitments and conducting clips, copper-nickel tubing for long-life brake lines, brasses cheaper than steel for hydraulic fittings, alloys for bearings, gears and valve guides.

24 Aerospace

High strength copper alloy control rod bearing for an Airbus (Delta (Manganese Bronze) Ltd) Copper-nickel-silicon material provides high strength, corrosion resistance, good bearing properties, high fatigue resistance and good thermal conductivity and gives the benefit in service of an efficient, reliable and therefore safe bearing construction material. Copper conductors form the vital links for power and communications. High performance copper alloys with a good strength-to-weight ratio, bearing strength and corrosion resistance are used for undercarriage components, aeroengine bearings, various bushing, head-up display unit components and helicopter motor spindles.

Saab fighter plane nose wheel strut with nickel-aluminium bronze bushings (Delta (Manganese Bronze) Ltd)

Electrical engineering

Copper windings of a modern, efficient electric motor.

25 High conductivity copper is used at constant operating temperatures up to 150°C under load with low contact resistance. The centrifugal forces developed at the high speeds at which electrical machines rotate mean that very high stresses have to be allowed for. This is provided by a material which not only gives the benefit of an efficient motor winding but is also readily drawn down in size to the wire or section needed. For short term uses such as spot and seam welding electrodes, operating temperatures can be much higher.

Boatbuilding and offshore

#

Aluminium bronze ship propeller and copper-nickel clad rudder (ICA) The need for marine corrosion and biofouling resistance leads to the choice of copper-nickel. This confers the benefit of negligible material loss by corrosion attack and, in the case of a vessel hull, means that costly dry-docking for removal of biofouling is not needed. Higher speeds can consistently be achieved due to less resistance to movement through the water. It may also be possible to design with smaller engines, reduced size of fuel bunkers and increased cargo space. On offshore structures the use of copper-nickel clad steel means that it is possible to design with smaller corrosion factors and reduce allowances for the stresses caused when strong currents drag on extensive biofouling.

Semiconductors

Scanning Electron Micrograph of new technology microchip showing the metal interconnects in a chip with six copper layers and one local interconnection layer of tungsten. Isometric of the CMOS 7S technology process At the bottom of the photo you can see a showing the new copper interconnections above magnification of the silicon transistor 1/1000th the tungsten local interconnect. Magnification x the size of a human hair. (Tom Way and IBM 50,000 (Fred Perkins and IBM Corporation) Corporation)

26

Copper is used in a new generation of higher performance, high function microprocessors that are smaller, lighter and require less power. The use of copper in the new microchips gives a performance gain of 30% and permits miniaturisation of current channel lengths to 0.12 microns, allowing up to 200 million transistors to be packed in to a single chip.

In these examples a number of different copper base materials are utilised in a variety of compositions and forms, it is important to recognise the benefit provided by the ease of machining, forming and joining of copper alloys in terms of lower cost products/components, produced on time. In addition to the global variety of applications for copper and its alloys, copper as an alloying content markedly improves other materials. This includes improvements to the strength of aluminium alloys, the corrosion resistance of the weldable structural steels and the corrosion resistance and strength of duplex (two phase) stainless steels and high nickel super-austenitic steels.

26 Section 2 – Availability

Forms available Copper alloys are readily available in a very wide range of cast and wrought (hot- or cold- worked) forms. It is an advantage that many forms are easily obtainable – this means that a huge range of small to large shaped components can be produced with a minimum of fabrication time and cost [8]. Fabrication involves processes such as hot forging, cold working, bending and machining. The sequence in which these operations may be carried out is shown in Figure 2.

Figure 2 – Production routes for the manufacture of copper and brass castings, semi-finished and finished products

27 'Near net shape forming' is a term applied to production processes that quickly and easily make shapes which can be readily finished by a minimum of further processing to give the final component shape. The choice between a cast or wrought starting shape will depend on more than just the final component required. For example: • Is the component hollow or does it have some internal shape? • What precise property combination is needed? • Ηow is it to be made? • Can the chosen alloy composition be produced by a particular fabrication method? (The properties of the cast and wrought versions of the same alloy type, where available, will not be identical.)

Wrought Forms Many wrought forms can be obtained – this allows the most economic to be selected relative to the final component shape. The following list gives an idea of some of the supply forms, which may be considered during the component design process.

Table 3 – Descriptions of terms for wrought products

Bar A wrought product of rectangular section along its whole length, supplied in straight lengths. Foil A rolled product with thickness of 0.10mm or less, supplied flat or in coil. Forgings A shape produced by hammering between open or closed dies, normally when hot. Plate A flat rolled flat product greater than 10mm in thickness. Rod A solid wrought form of uniform cross section (circle, square or regular polygon) along its whole length, supplied in straight lengths. Profile A solid wrought form of irregular cross section produced as extrusions from specially shaped dies. Round tube A hollow form, circular in cross section, supplied in straight lengths or coils. Sheet A flat rolled product with uniform thickness from 0.2 up to and including 10mm. Strip Produced by rolling with uniform thickness from 0.1 to 5.0 mm supplied in a coil. The thickness does not exceed one tenth of the width. Wire A solid product supplied in coil form or on spools or reels.

Castings (There is a comprehensive CDA book on this topic ‘Copper and Copper Alloy Castings – Properties and Applications’.)

Casting processes using refractory moulds

Sand casting Most castings are produced by this technique. Moulds are made from sand bonded with clays or silicates or various organic mixes. Cores to define the internal shape of hollow castings are also

28 of sand – they are accurately located in the hollow cavity made inside the sand mould – the cavity having been made by a pattern, usually constructed from wood.

Brass breather valve sand casting cast as one piece with simple fettling required and minimal scrap, production costs are kept low (Enfield Foundry Company Ltd)

Shell moulding

Gear for locomotive braking system cast in aluminium bronze ensuring long life in aggressive operating conditions (British Rail) Investment (precision) casting – investment casting by the ‘lost wax’ process has been used for centuries to produce statues. The process uses a pattern of wax, which is coated with several layers of refractory slurry to build up a shell. Finally, the wax is melted out and a cavity remains into which is poured the molten metal.

29 Clarinet keys precision cast to a near-net shape that needs little finishing beyond fettling, polishing and decorative plating (Boosey and Hawkes Ltd)

Casting by permanent mould processes Permanent moulds (usually of metal) are often used as an economic way of producing a high volume of castings. After the molten metal has been poured in to them and allowed to solidify, the moulds are opened so that the component can be removed and then closed again and made ready for the next casting.

Gravity diecasting In this process the metal moulds or dies (normally in steel) are made in two halves which open to allow removal of the casting.

Sectioned gravity diecast brass tap showing structure of hollow core (Armitage Shanks Ltd)

Pressure diecasting Molten metal is injected into steel dies under high pressure. Multi-cavity dies are employed to give high production rates and reduce costs.

Pressure diecast brass components with close tolerances and thin walls for a variety of applications (J W Singer Ltd)

Centrifugal casting This process involves the pouring of molten metal into a steel mould or die rotating at fairly high speed.

30 Spuncast aluminium bronze pipes used to suspend seawater pumps below lowest water level on offshore oil platforms (Spunalloys)

Continuous casting Used for the production of rods, sections and hollows, this technique utilises a graphite die of required shape into which metal pours from a furnace. The metal solidifies as it passes through the water-cooled die.

A selection of the complex sections which can be continuously cast to very accurate dimensional tolerances (Delta Enfield Metals Ltd)

Buying copper and copper alloys Copper and copper alloy products can be bought from foundries, manufacturers or stockists as appropriate. The CDA Information Service can discuss requirements and give the names of contacts known to be able to supply. Costs of fabricated materials may be quoted per unit length but are more likely to be sold by weight. As with castings, the price reflects the cost of the metal plus production and handling costs. The price of the metal does vary according to supply and demand but can be agreed at the time an order is placed.

Manufacturers Medium and large sized orders for semi-finished raw material are best obtained directly from fabricators, especially if the requirement is ongoing. This applies particularly where hot stampings are needed or if extrusions need to be made through specially shaped dies. Needs for compositions, properties and surface finishes to suit particular applications, can be discussed and special requirements can be agreed for economic quantities. Over recent years, manufacturers have made large investments to improve production facilities to meet requirements for reproducible close tolerances on dimensions, composition and properties at minimum production costs. Economic order sizes for special orders are now

31 significant. Delivery lead times may be typically about eight weeks but are subject to variation with mill loading and any die production requirements. Some fabricators have an associated stockholding facility.

Foundries When required cast to shape, items will be procured from a foundry. The components will be made from patterns prepared from drawings but with allowances made for feeding the liquid metal in to the casting and for reduction in size due to solidification shrinkage. The price agreed will depend on the cost of the alloy plus the costs appropriate to the casting method, pattern costs and the amount of finish machining and testing that may be required. Familiarity with casting techniques is useful when designing components to be produced to good quality standards at minimum cost. Discussions with foundry personnel will be found invaluable at this stage.

Stockists Small and medium size quantities of fabricated copper and copper alloys are best bought from a stockist. Material to most common specifications and sizes is frequently available from stock for delivery within 24 to 48 hours and can be programmed for regular supply of small quantities. This ‘JIT’ (Just in Time) approach to material management has brought considerable benefits to manufacturing industry. It means that working capital and storage space are not tied up in raw material stocks. The supply source chosen must be knowledgeable, reliable, flexible and hold large stocks of a wide product range, generally of a greater range than can be supplied by any one manufacturer. From their stock lists it is possible to select the materials most appropriate or to discuss requirements with trained staff. Many stockists can cut to special lengths or sizes and arrange for surface finishing and protective coatings.

London Metal Exchange Besides being essential for the production of components, copper is also a traded commodity. Daily dealings on the London Metal Exchange fix the price for that day. Deals can also be made to buy copper at a fixed price some time in the future and prices for three months ahead are commonly quoted to enable production costs to be stabilised. According to market conditions, prices for future delivery may be higher or lower than the spot price on the day. Many 25 tonne lots are traded each day as buyers meet their needs and sellers supply them. Most copper producers supply their copper direct to the manufacturers, priced at a contracted rate based on current LME values. Many good newspapers quote recent LME prices in their ‘commodities’ news section.

Primary Copper Reserves The estimation of available resources of copper cannot be an exact science. There are: • Deposits found, evaluated and being worked. • Deposits known to be available but not yet worked. • Deposits known to be available but not yet economic • Deposits yet to be found. • Deposits on the seabed still being built up by precipitation from the sea.

32 The usability of a deposit depends of course on the average copper content to be economic, and also on the availability of transport and fuel. Proven reserves workable with present techniques are about 310 million tons [10}, more than sufficient for 50 years. Present estimates are that there are over 2,120 million tons of copper likely to be available in other deposits, sufficient for over 250 years at current extraction rates [11]. More reserves remain to be found as more land is geologically explored. As extraction techniques on land improve, the minimum economic copper content is reduced, making even more available from known resources. The extraction of copper from seabed deposits of modules is feasible, but techniques for raising the ore to the surface economically are still being developed. Recycling has always been economic. With increased emphasis on recovering, separating and re-using all materials, it is making an increasing contribution to supplies.

Recycling Copper and Copper Alloys The entire economy of the copper and copper alloy industry is dependent on the economic recycling of any surplus products. Process scrap arising from manufacturing processes is saved and sold for recycling to keep down the cost of the product. On average, 40% of all production is from recycled metal. For some products the proportion is over 90%. Copper and copper alloy scrap can be recycled relatively cheaply, with low power consumption, and with minimal losses. The recycling of copper and its alloys plays an important part in the economics of production and has been undertaken since the copper industry began. The cost of the raw material can be significantly reduced if an alloy can be made with recycled material. If the scrap is pure copper and has not been contaminated by other metals, a high quality product can be made from it. Similarly, if scrap is kept segregated and consists only of one alloy composition it is easier to remelt to a good quality product conforming to standard. When costing the production of a component, allowance can be made for recovery of money through the reclamation and sale of clean process scrap. There are many forms and sources of scrap, which may be utilised. Components that are beyond their useful life are a valuable source. In addition, scrap from manufacturing processes such as trimming, fettling (of castings) and machining is most useful. Good quality high conductivity copper scrap, for example, generated during power cable drawing, can be recycled by simple remelting. Where contamination has occurred, it is normally remelted and cast to anode shape so that it can be electrolytically refined. In cases where scrap is contaminated with certain elements such as tin and lead - as a result of being tinned or soldered - it is more economic to take advantage of this contamination to produce a copper alloy (gunmetal or bronze) which needs these additions as alloying elements. Where copper and copper alloy scrap is very contaminated and unsuitable for melting, it can be recycled by other means to recover the copper either as the metal or to give some of the many copper compounds essential for use in industry and agriculture. The recycling of brass by melting is a basic essential of the industry. All of the feedstock for the manufacture of billets for extrusion of rod comes from scrap, including • process scrap such as offcuts from within the mill, • process scrap such as turnings from machine shops • scrap from brass components being recycled after a useful life.

33 Figure 3 – Recycling of copper

This summarises, by decreasing copper content, and hence conductivity, the types of scrap that can arise and the products most efficiently made from them. The material being recycled is shown on top of the diagonal; the products that can be made from it underneath. Products with higher alloy content than the scrap are economically made. Products of high purity can only be made economically from primary copper or high grade scrap.

For thousands of years, copper and copper alloys have been recycled. This has been a normal economic practice, even if the loss of some works of art is regretted by some. One of the wonders of the Old World, the Colossus of Rhodes, an enormous statue at the entrance to Rhodes Harbour, was said to have been made of copper. No trace of it remains since it was recycled to make useful artefacts. In the Middle Ages it was common that after a war the bronze cannon were melted down to make more useful items. In times of war even church bells were used to produce cannon.

Scrap copper baled for recycling (Ampthill Metal Company Ltd)

34 Sustainability of Copper Supplies Copper can be regarded as one of the few metals that is fully sustainable. As described above, it is fully economic to recycle copper and its alloys. As an essential trace element for plant, animal and human life it also cycles through the entire food chain. In addition, copper that is leached out of agricultural or other land flows with the water down the rivers and in to the sea. Here it eventually precipitates out in areas where the water chemistry is suitable. High concentrations of mineral-rich nodules are found in these areas. Deposits of this type are thought to have formed the high copper content found in some of the ore bodies now being worked after earth movements have forced them well above sea level. While it is not yet economic to extract copper from undersea nodules, that time will not be long coming.

35 Section 3 - Copper in Health and Environment

Copper and Health Copper as a trace element is essential to the health of plants, animals and humans[12] . Too little copper can cause deficiency diseases. We absorb copper into our bodies through nutritional intake i.e. meat, fish, cereals and vegetables.[13] Copper is an effective biocide which results in it controlling organisms such as legionella in water circulating systems and in it restricting marine biofouling when used, for example, as copper-nickel alloy cladding on boat and ship's hulls and offshore structures. Copper compounds are used for their beneficial fungicidal effects on plants; for example, cupric carbonate is employed in copper-based fungicide.

Fungicides containing copper are essential for the production of healthy grapes (Vin Callcut) The use of brass or copper instead of other materials for doorknobs and fingerplates in hospitals helps to reduce the spread of nosocomal infections such as the common cold. Copper bracelets are worn by many people and are said to improve the health of the wearer; for example, absorption through the skin can help to relieve arthritic discomfort. We cannot live without Copper Copper is one of a relatively small group of metallic elements that are essential to human health. These elements, along with amino and fatty acids as well as vitamins, are required for normal metabolic processes. Copper is a constituent of many enzymes involved in numerous body functions and is a constituent of hair and of elastic tissue contained in skin, bone and other body organs[14]. There are a number of important copper-containing proteins and enzymes, some of which are essential for the proper utilisation of iron. Dietary deficiency is rare, but does occur in certain acquired or hereditary disorders that impair intestinal absorption. Several abnormalities have been observed in copper-deficient animals, including anaemia, skeletal defects and degeneration of the nervous system. The enzymes act as catalysts to help many body functions. Amongst others, this is especially important for the health of heart and arteries. However, as the body cannot synthesize copper, regular amounts of copper must be included in a normal diet.

36 Everyone needs to know about the benefit to health of a well balanced diet including copper as a trace element (Vin Callcut)

How much copper? The adult body contains between 1.4 and 2.1mg of copper per kilogram of body weight. To maintain this concentration, it is recommended that the daily intake of copper should be 0.4mg/day for children aged 1-3 years and 1.2 mg/day for adults. Copper-rich foods include most nuts, seeds, chickpeas, liver and oysters. Natural foods such as cereals, meat and fish generally contain sufficient copper to provide up to 50% of the required daily intake. The copper content of supply water is usually measurable but insufficient in its own right to provide the balance of the normal daily intake. It is rare that problems are found with too much copper in a system. Most copper salts in excess are powerful emetics and overdoses are usually rejected. Only very occasionally, as with the very rare Wilson’s Disease, does a body retain excessive copper.

Copper in the Environment Being a trace element essential for the health of plants, animals and humans, the distribution and concentration of copper in the environment is important. Typically there is 1 µg/l of copper in fresh water supplies. The optimal concentration in living organisms is around 1,000 µg/l and the metabolism normally adjusts the concentration to be within optimum range. In the ground, copper is normally present in compounds that are not easily soluble in water. Only a limited percentage, normally less than 1%, is available in soluble form for bioavailability. This can be taken up by the roots of plants as required and is then recycled as leaves and wood decay, concentrating in the top 100mm or so of the soil. Additionally or alternatively, copper is replenished when organic manure is spread. Intensive farming without this recycling can lead to copper deficiency that has to be made up when fertiliser is applied.

Copper in Farming Besides being essential for the health of plants, animals and humans, copper and copper compounds can be used in fungicides, biocides, bacteriastats, molluscicides, insecticides and preservatives[15]. Copper is a vital ingredient of Bordeaux mixture, Burgundy mixture, Cheshunt compound and Paris Green. Nearly three hundred plant diseases amenable to control by copper fungicides are listed in ‘Uses of Copper Compounds’[16].

37 Section 4 - Copper and its Alloys

Coppers There is a wide range of shapes/forms available in copper base materials. There is also a very large variety in generic types of copper alloy and chemical compositions available. This provides many possible property combinations, often unique to copper base alloys, making the alloys suitable for applications in virtually every area of human activity. Coppers and copper alloys are produced to conform to a wide variety of national and international specifications prepared to suit differing conditions and requirements. All manufacturers and good stockists are approved to supply material, if required, under the quality assurance requirements of BS EN ISO 9000 series. The starting point for the production of coppers and copper alloys in the range of shapes available is the casting of molten copper into one of five standard 'refinery shapes'. Modern production processes are usually continuous and the cast product is either cut to length by flying saws or passed directly towards mills for fabrication. The shapes - ingots, ingot bars, billets, cakes and cathodes - are appropriate to further processing (often through intermediate forms) to specific final shapes/forms. In the case of copper alloys the shapes for further processing are cast from melted copper ingot with the addition of appropriate master alloys to provide the elements needed for the alloy type. The majority of copper used for electrical purposes is High Conductivity Copper made from material that has originally been electrolytically refined to high purity before being melted and cast without the addition of alloying elements or impurities. A little oxygen is all that is present to ensure that conductivity remains high, now around 101.5% compared with the standard set by the IEC in 1913. For applications where good welding and brazing properties are more important than conductivity, phosphorus-deoxidised copper is used. This is the standard type of copper used for tubing and for water cylinders and pressure vessels. Further details of these materials follow. Other types of copper are described in the CDA book No 122 'High Conductivity Coppers for Electrical Engineering'.

Copper alloys Copper forms alloys more freely than most metals, and with a wide range of alloying elements. Zinc, tin, nickel and aluminium are the most common alloying additions and produce the following alloy types - COPPER with • tin makes Bronze • tin and phosphorus makes Phosphor bronze • aluminium makes Aluminium bronze • zinc makes Brass • tin and zinc makes Gunmetal • nickel makes Copper-nickel • nickel and zinc make Nickel silver

38 Figure 4 - Some of the effects of alloying additions on the properties of copper

Alloys based upon copper are classified as non-ferrous (ferrous materials are iron-base, for example, steel). Useful alloying additions of other elements to these alloys in small amounts can include aluminium, arsenic, beryllium, cadmium, chromium, cobalt, iron, lead, manganese, nickel, niobium, oxygen, phosphorus, silicon, silver, sulphur, tellurium, tin, zinc and zirconium. All are found in standard coppers and copper alloys and are added as required in small amounts to give specific properties suitable for many demanding applications. Some alloying elements have been in use with copper since early times. Initially there may have been no full understanding of what type of copper alloy had been produced and why it possessed its particular characteristics. However, the development of metallurgical and corrosion science knowledge has provided many answers and also led to the use of other alloying elements with copper. Further development of copper alloys is still taking place and will continue into the 21st century to meet modern application challenges.

Copper and High Conductivity Copper Alloys A third to one half of all copper produced is used in some form for applications in electrical engineering and the supply of domestic electricity. The reason is simple - among the readily available engineering materials copper is unique. Not only is it extremely ductile and capable of being formed into a wide range of products with ease, but it has almost uniquely high values of thermal and electrical conductivity, exceeded only by silver. The high electrical conductivity is especially important for the efficient transmission and utilisation of electrical energy, and copper is therefore the principal material for busbars[17], electric cable and windings[18].

39 High conductivity copper busbars for carrying heavy electric currents (Vin Callcut) These are the popular types of copper, each suitable for a variety of end uses. • High conductivity (HC) electrolytically refined copper (sometimes known as tough pitch copper or 'electro'), with a nominal conductivity of 100% IACS (International Annealed Copper Standard), is used for most electrical applications such as busbars, cables and windings. High conductivity copper is very readily worked hot and cold. It has excellent ductility which means that it can be easily drawn to fine wire sizes and it is available in all fabricated forms. • Deoxidised copper (usually deoxidised with phosphorus - or boron in the case of castings) is a material that can readily be brazed or welded without fear of embrittlement. It may be known colloquially as 'Deox' and is used for the manufacture of tubing for fresh water and for hot water cylinders. • Oxygen free high conductivity copper (OFHCTM is a registered trade mark) is produced by casting in a controlled atmosphere and is used where freedom from the possibility of embrittlement is required. • A special grade of oxygen-free high conductivity copper (certified grade) with low residual volatile impurities is used for high vacuum electronic applications such as transmitter valves, wave guide tubes, linear accelerators and glass to metal seals. • Free-machining copper - An addition of 0.5% sulphur or tellurium raises the machinability rating of copper from a rating of 20% (based on 100% for free-cutting brass) to 90%. Applications for these free-machining grades include electrical components, gas-welding nozzles and torch tips and soldering iron tips. A wide variety of high conductivity copper alloys is available for special purposes of which three are the most common. Copper-silver (0.01 to 0.14% Ag) has better creep resistance than copper itself and is therefore used in the manufacture of commutators, alternators and motors, where the capacity to resist temperature and stress is essential. Copper-cadmium alloys, with about 1% cadmium, are used for their wear-resistant properties for some heavy duty catenary wires, which are familiar as the overhead electrical conductor wire seen on electric railway systems.

40 Commutator for a heavy duty DC propulsion motor (Laurence Scott and Electromotors Ltd) For electrical applications such as resistance welding electrodes where service is at high temperature under heavy stress, a copper-chromium (up to 1% Cr) alloy is often employed. This is heat treatable to give good room temperature mechanical properties which are maintained well as the operating temperature rises (400° continuous rating is possible) and it retains conductivity of around 80% IACS. The addition of up to 0.2% zirconium confers even better elevated temperature fatigue resistance. Deoxidised copper is used for the other major area of application of the coppers in building, the principal uses being for central heating systems, pipe for gas and water supply, household electrical wiring and sheet for roofing. The ability of copper to form a protective and aesthetically pleasing surface, or patina, by weathering has encouraged its use for roofing large buildings over many centuries.

Bronzes and Phosphor Bronzes Binary alloys of copper and tin are called bronzes and can contain up to 12% tin. An increase in hardness and strength is gained at minimal cost by the addition of phosphorus to a level of around 0.25% to make phosphor bronzes. Tin contents range from 4% up to 8% in wrought materials or higher if the alloy is used as cast. Alloys containing the higher tin level are particularly suitable for severe operating conditions. Possessing high corrosion resistance, excellent tensile and fatigue strength, superior wear resistance and bearing/frictional properties, this type of alloy finds application for heavy duty bearings, bushes and gears, high performance engine components, high strength switch parts, thrust washers, slides, pistons and many others. Leaded phosphor bronzes can be produced that machine almost as easily as free-cutting brass.

Close tolerance bearings for heavy duty use machined from continuously cast copper alloys such as phosphor bronze and leaded bronze (J Roberts Components Ltd)

41 Special compositions with around 20% tin are suitable for bell founding. These alloys are brittle and of little use for more general engineering purposes.

Aluminium Bronzes (Copper-Aluminium Alloys) These are a range of copper alloys containing up to 14% aluminium and frequently other elements such as nickel, iron, manganese and silicon. Varying the proportions of these results in a range of strong, tough alloys with excellent resistance to corrosion and wear that are ideal for a wide variety of demanding engineering applications[19]. Their strength, and in many respects their corrosion resistance, is better than most stainless steels, especially in aggressive marine environments[20]. They are available both as high- integrity castings in weights up to many tons and in the usual wrought forms such as plate, forgings, extrusions and as welding wire. They are readily weldable for fabrication of large components. [21] The aluminium bronzes possess the excellent natural corrosion resistance of all copper alloys enhanced by the protective film of aluminium oxide formed very rapidly under normal operating conditions. If damaged, this film is self-healing, which means that the alloys can be used in service conditions when abrasion can be expected. This type of alloy is specified for the manufacture of pumps, turbines, propellers, valves, tees, branches and other water fittings, pressure vessels, pickling hooks, heavy duty journal and flat bearings, gearbox components and masonry fixings. Nickel aluminium bronzes containing around 10% aluminium, with additions of iron and manganese to increase strength and toughness still further[22], are widely specified for applications on surface and submarine naval vessels and are often produced to NES (Naval Engineering Standard) designations. Silicon bronzes and aluminium silicon bronzes contain silicon to a level of 1% up to around 4% and offer low magnetic permeability for navigation equipment and mine hunting vessel equipment. High aluminium alloys are cast to make very hard die materials for pressing steels and for glass bottle moulds.

Brasses Brasses are copper alloys in which the main alloying element is zinc. The generic term 'brass' covers a wide range of materials suitable for many different types of application[23]. Good corrosion resistance, machinability, formability and conductivity are properties characteristic of all the brasses together with toughness retained above and below ambient temperatures, good spark-resistance and low magnetic permeability[24]. The old British Standards included 37 different compositions of wrought brasses and 9 of the most popular casting brasses, so correct choice of brass is important. The range of compositions preferred across Europe and included in the new BS EN series of standards gives even more choice. Copper-zinc alloys with up to about 30% zinc have a single-phase metallurgical structure, the alpha phase, a solid solution of zinc in copper. Cap copper (up to 5% Zn) is used for ammunition percussion caps. The gilding metals (10 to 20% Zn) are used for architectural metalwork, papermaking, jewellery strip and applications requiring suitability for brazing and enamelling.

42 Brass door furniture - Economy, longevity and durability are only some of the attributes needed for door furniture. Brass also has strength, wear resistance, bactericidal properties and an attractive appearance (Vin Callcut)

The cartridge brasses (30% Zn) have the maximum ductility of the copper-zinc range and are used for deep drawing. Common brass, containing 36% zinc, is the most usual composition used for brass sheet.

Light Bulbs- Good quality light bulbs have brass caps which will last the life of the bulb without corroding or sticking in the holder. They are made by repetition stamping from brass sheet and the webbing scrap is recycled.(Lamp Caps Ltd) Brasses with more than about 37% zinc have a binary metallurgical structure (two-phase) and are known as alpha-beta alloys. The beta phase is readily deformable when hot, and these alloys lend themselves more readily to hot forming techniques than almost any other alloy used in engineering. Such compositions, all derived from Muntz metal, with about 40% zinc, allow the production of complex machinable high strength shapes at low material cost. Other elements are added to the brasses to produce materials for different applications. Free- machining brass (containing 39% Zn and 3% Pb) has for decades been the standard alloy against which the machinability of other metals has been judged. The lead is present as fine particles that help chip forming of the swarf so that it can clear away from the tool tip.

43 Turned brass components - These components are all made rapidly and economically on automatic lathes from extruded high-speed machining brass rods and hexagonal sections (Delta Extruded Metals Co Ltd) Figure 5 shows comparisons of machinability reported by an experienced manufacturer[25]. Machining speed is not the only factor that affects the cost of machined components. Amongst others is the cost of keeping the tool tip clear of long strands of swarf produced from non free- machining materials. The addition of manganese, iron and aluminium produces high tensile brasses (sometimes known as manganese bronzes) which, with enhanced strength and resistance to wear, impact and abrasion, are used for architectural and heavy duty engineering applications.

High tensile brass bolt and nut for marine service (Vin Callcut)

High tensile brass (with higher alloy content - particularly aluminium - than normal high tensile brass). This offers very significant increases in strength and hardness and similar to those properties associated with aluminium bronzes and is employed for aircraft landing gear components. When about 1% tin is added to copper-zinc, Naval brass or Admiralty brass is produced depending upon the ratio of copper and zinc. Under certain conditions in seawater and aggressive domestic water supplies, brass can be subject to a corrosive attack called dezincification. The addition of around 0.1% arsenic produces an alloy free from this problem and, meeting the requirements of the water supply industry, is used for pipe fittings, stop-cocks, water meters and other components of plumbing and heating installations. Another special brass with a Trade Name of ‘Tungum’, contains aluminium, nickel and silicon additions to give a combination of high strength and ductility with excellent resistance to corrosion and shock. In tube form it is used in the hydraulic systems of offshore platforms and

44 associated vessels as well as winch controls, lifeboat davit and deck crane systems and marine drive systems. It also finds application in high pressure gas storage systems, aircraft production and test rig hydraulic systems.

Tungum tube installation within the control cabin of an offshore pedestal crane (Stothert and Pitt Ltd)

Gunmetals These are copper-tin-zinc alloys that have improved corrosion resistance due to the tin and good fluidity for casting conferred by the zinc. Today most gunmetals have an addition of lead to improve machinability.

Gunmetal water fittings give a have a long service life above and below ground (F W Birkett)

Nickel Silvers These copper-nickel-zinc alloys, closely related to the brasses, contain no silver but take their name from their silvery appearance - which becomes whiter with increasing nickel content - and ability to take a high polish. Nickel content can range from 10 to 25% though for most purposes 18% is the maximum - an alloy with this content is commonly used for spectacle frames.

45 Spectacle frames - Nickel-silver, gold plated, has the good strength, ductility and corrosion resistance necessary for the fabrication of precision frames for spectacles (Vin Callcut) The mechanical properties are somewhat higher than those of the brasses. The alloys are used extensively for decorative ware and for cutlery, especially for goods destined for silver plate, which is stamped EPNS (electroplated nickel silver). Strip and wire are used to make springs and contacts for electrical equipment. In architectural applications they are sometimes known as ‘silver bronzes’ and can be used for decorative metalwork, door handles and handrails.

Copper-Nickel alloys Like the aluminium bronzes, the copper-nickel alloys (or cupronickels) have come into their own during this century. Following the 1914-1918 war the British Navy required condenser tubes with improved resistance to failure when handling seawater in harbours, estuaries and other polluted waters. This led to the development of copper-nickel-iron alloys in the 1930s. The three most used alloys of copper and nickel contain around 1, 10 and 30% nickel with other elements[26]. The addition of nickel to copper improves strength and corrosion resistance but good ductility is retained[27]. Excellent resistance to corrosion attack by marine environments is combined with the resistance of copper to biofouling.

Copper-nickels can be readily welded to build up complex fabrications very economically (James Robertson Ltd) 90/10 copper-nickel, containing 1% each of iron and manganese, is used for seawater piping aboard ships[28] and offshore oil and gas production platforms[29]. The alloy is also employed in sheet form to sheath the hulls of ships[30] and clad the legs of offshore platforms. 70/30 copper-nickel was developed initially to provide an even better material for condenser tubing.

46 Other applications for these copper-nickels include plant construction for desalination by distillation, vehicle hydraulic systems and the production of coinage. In the past few decades high strength copper-nickels (with strength up to 5 times that of the alloys already described and similar to that of carbon steel) have been developed. These alloys, strengthened by the presence of minute nickel-aluminium precipitates in the microstructure, are selected for bolting (with resistance to hydrogen embrittlement) and other highly loaded components on naval vessels and offshore oil and gas structures. High strength cast copper- nickel, containing chromium, is used for pumps and valves in naval vessels.

Copper-Nickel-Silicon During the second half of this century wide use has been made of an alloy based upon copper and containing 2.0 to 3.5% nickel and 0.4 to 0.8% silicon. This precipitation-hardening alloy possesses high strength and good ductility combined with high electrical conductivity and thermal conductivity 40% that of copper. Resistance to corrosion in marine and industrial environments is excellent and the alloy has good anti-frictional and bearing properties. With a magnetic permeability <1.001, the alloy is essentially non-magnetic. The versatility of this type of alloy is demonstrated by widespread use in diverse industry sectors. These applications include valve guides, piston tops and little end bushes in high performance internal combustion engines, aero-engine bearing cages, aircraft undercarriage components, gears and bushes, resistance welding electrodes, electrical contacts, naval vessel hose connectors, piston crowns, plastics moulding dies, clutch plates in marine engines and non- magnetic naval vessel winches.

Piston top for high speed two-stroke Deltic diesel engine - A high strength copper alloy with excellent conductivity is required to give long service life in the high performance, high speed Deltic diesel engine (Vin Callcut)

47 Copper- Beryllium Alloys

Copper-beryllium oil and gas components - These are hard wearing components with good anti-galling properties, high strength and corrosion resistance and are used in aggressive offshore environments (Brush Wellman) The addition of beryllium to copper gives an alloy capable of being heat-treated and cold worked to provide exceptionally good mechanical properties at room and at elevated temperatures. For many years these alloys have been used extensively for demanding applications such as springs, contacts, heavy-duty engineering and electrical components and moulds for plastics and glass production. Because of their high strength and hardness they are used for the manufacture of non-sparking tools for use in hazardous environments. There are two basic types of alloy - one contains nearly 2% beryllium with some nickel and/or cobalt, the other contains about 0.5% beryllium and 2% cobalt. There are health hazards involved when beryllium fume is present during melting or welding operations.

Copper in other Metals Apart from use in the copper-base alloys, there are other base metals to which copper can be added, though of these only iron, nickel and aluminium have any engineering importance. Structural steels can be made resistant to weathering and heavy progressive rusting under many conditions by the addition of copper. These grades are known as weathering steels and contain about 0.5% copper. The addition of copper (around 2 to 4 %) to duplex stainless steels and high nickel super austenitic steels enhances corrosion resistance in acid environments and can also confer greater resistance to certain forms of attack by seawater. The most important alloy of nickel with copper is known as Monel metal and contains about 30- 35% copper. It originated from the copper-nickel mattes derived from the mixed ores found at Sudbury, Ontario. These mattes were smelted to give the alloy directly. It was found that it was highly resistant to many forms of corrosion, especially in chemical processing and marine applications. Alloys of aluminium with about 4% of copper are age hardening and by careful choice of composition and thermomechanical processing, very high levels of mechanical strength can be obtained, though at the expense of corrosion resistance. The original aluminium-copper alloy was known as ‘Duralumin’.

48 Copper Compounds Copper sulphate is commercially the most important copper compound, once called ‘blue vitriol’ from its close association with sulphuric acid. It is generally the starting stock for the manufacture of most other copper compounds. World consumption is around 200,000 tons per year, of which approximately 75% is used in agricultural applications. Other uses include: • electrolyte for copper refining • anti-fouling paints • catalysts for many industrial processes in the petrochemical and rubber industry and for textile manufacture. • additives to cement for controlling setting rate and lichen growth • addition as fungicide to plaster • mordants for dyeing • colourings for paints, glass and fireworks • preservatives for paints, adhesives, timber, textiles and bookbindings Cupric oxide, cuprous oxide, copper acetate, cupric chloride, copper oxychloride, cupric nitrate and copper napthenate are used selectively for these purposes for their ease of use or other special properties.

49 Section 5 - Making Components

Fabrication, Joining and Finishing (‘Design for Production’ is the title of a comprehensive CDA book on this topic[31] )

Fabrication This is a term, which describes the means by which the required form/shape is produced. The casting techniques referred to in the section on 'Forms Available' are fabrication methods. To these we need to add methods involving hot and/or cold working since the various wrought forms available are produced by these methods. A number of fabrication processes will often be required to produce the shape needed, for example, a cast billet or cake (which may be a piece cut from a continuous cast length) is used as the starting material for hot working to shape. The final shape may be made by more than one hot working process and could also require a cold working method to be adopted - machining will frequently be employed to achieve the dimensions required. Electro-deposition is employed for the production of printed circuit boards. All these processes have been examined in detail over the past years to continue development of techniques to improve quality, raise production rates and reduce the cost of processing at the same time as improving working conditions and the effect on the environment.

Hot Working The main processes are rolling, extrusion (forcing hot metal through a die), forging (hammering between open dies to produce simple shapes such as blocks, discs, shafts and rings - hollow forgings can be produced with the use of loose tooling/formers) and stamping (a near-net shape process involving forging between shaped, closed dies). Other processes are - metal powder compaction, ‘Hipping’ at very high isostatic pressures and metal injection moulding.

A small hot rolling mill for brass cakes, reducing the thickness from 150mm to 6mm (Vin Callcut)

Cold Working Processes used with sheet and strip are bending, stamping from sheet or strip, spinning of the dished ends for vessels, rolling, deep drawing and thread rolling. Wire is usually finished to size by cold drawing.

50 Multi-spindle wire drawing machine (Delta Enfield Wires)

Machining Machining of all coppers and copper alloys can be successfully carried out using conventional techniques[32]. Materials with special additions, such as leaded brasses and sulphur, tellurium or leaded coppers, are generally easier to machine. They can be used to manufacture fully finished components with a cost much less than that of others made from materials of lower initial cost. The ease of machining has a significant effect on the rate at which components can be produced. This makes them cheaper than similar components made from other materials. Relative machinability rates of various metals are given below.

Free-machining brass gives fine chips of swarf which minimise tool wear and the need for lubrication (Vin Callcut)

51 Figure 5 – Comparison of machinabilities of common engineering metals

Joining Joining of copper base materials can be easily achieved by a wide variety of techniques[33]. That chosen will depend upon factors such as speed, cost, required joint strength, conductivity and corrosion resistance. Techniques available for selection include arc welding, induction and resistance welding, friction welding, cold pressure welding, brazing, silver soldering, soft soldering, mechanical joining and the use of adhesives. Further details are included in CDA Publication No 98 ‘Joining of Copper and Copper Alloys’.

Fabrication of tubular copper-nickel components to form a bend for seawater pipelines for use on a North Sea Oil platform (George Clark and Sons (Hull) Ltd)

Finishing Finishing methods, which are employed, include pickling clean in an acid solution (sometimes followed by bright dipping in an acid mixture), polishing, plating (less often required for corrosion protection with copper alloys) and lacquering. Techniques for plating copper are well established. Lacquers used should be suitable for copper-based materials in order to inhibit tarnishing. Care should be taken to select lacquers suitable for use on copper, brass and other copper alloys. These should include tarnish inhibition of the type described in the CDA book 'Clear Surface Finishes'[34].

52 Section 6 - Mining and Extraction

Mining of ores and copper extraction Copper minerals and ores are found in both igneous and sedimentary rocks. Mining of copper ores is carried out using one of two methods. • Underground mining is achieved by sinking shafts to the appropriate levels and then driving horizontal tunnels to reach the ore. • Open pit mining is employed when the ores are near the surface and can be quarried after removal of the overlaying surface layer.

Bingham Canyon copper mine (Vin Callcut)

Typical copper mineral (Codelco)

Copper and Mineral Ores Copper is found in the earth’s crust and the oceans although the amount in the latter is thought to be negligible, amounting to no more than about 8 months mine production at present day rates. The upper 10 kilometres of the crust is thought to contain an average of about 33 ppm of copper. For commercial exploitation, copper deposits generally need to be in excess of 0.5% copper, and preferably over 2%. The known reserves of higher-grade ore in the world amount to nearly 1 billion tons of copper. At the present rate of smelter production, which is about 9 million tons a year, known reserves of copper could be depleted in about 100 years. However, successful exploration for new mineral deposits, technological advances and the increased recycling of scrap is forestalling the eventual depletion by a considerable period. As previously mentioned, these advances in technology now known mean that supplies are estimated to be assured for a minimum of 250 years. Future developments and sourcing may extend this time indefinitely.

53 Over 160 copper minerals are known, of diverse appearance and colour. Most of these are very rare, and fewer than a dozen are at all common. Of these the most brilliantly coloured are the bright green banded malachite; bornite, which is iridescent, giving rise to its alternate name of peacock ore, and chalcopyrite, a mixed sulphide of copper and iron, which is a bright yellow crystalline mineral resembling pyrite, or ‘fool’s gold’. Table 4 shows some of the most common copper minerals. Some of these have long had a value in their own right, such as malachite, prized for its unusual and pleasing appearance - never the same and always striking - and used for millennia in jewellery and ornaments.

Malachite - This copper mineral has an unusual and striking appearance and has been used for millennia in jewellery and ornaments.

Table 4 – Minerals of Copper

Mineral Composition Wt Colour Lustre % Copper Native Cu 100.00 Copper red Metallic copper

Cuprite Cu2O 88.8 Red Adamantine to earthy

Chalcocite Cu2S 79.9 Dark grey Metallic Covellite CuS 66.4 Indigo blue Bornite Cu FeS 63.3 Golden brown to copper 5 4 Metallic red

Malachite CuCO3Cu(OH)4 57.5 Bright green Silky to earthy

Azurite 2CuCO3Cu(OH)2 55.3 Blue Vitreous to adamantine

Antlerite Cu3SO4(OH)4 53.7 Green

Chrysocolla CuSiO32H2O 36.2 Bluish green, sky blue, Vitreous to earthy turquoise

Chalcopyrite CuFeS2 34.6 Golden yellow Metallic to opaque

The largest single mass of native copper was found in Minnesota in 1857 and weighed 420 tons, but most are usually very much smaller and native copper is in fact of no commercial importance. There are two varieties of commercially significant copper ore - the ‘sulphide’ ores and the ‘oxidised’ ores. The principal sulphide minerals are chalcocite, covellite, bornite, and chalcopyrite. The ores often consist of one or more of these minerals in a matrix of some variety of copper-free rocks.

54 The rock, or ‘gangue’ has to be separated from the sulphide minerals in order to smelt the metallic copper from the ore. By far the greatest proportion of copper is extracted from the sulphides. These ores originate from sulphur-bearing magmas, which have separated into metal sulphides and siliceous melts. The copper has concentrated almost entirely into the sulphide fraction, and if this becomes separated from the siliceous melt it can become deposited in veins by hydrothermal or other geological activity. Where these mineralised rocks become outcropped or shattered, the sulphide minerals undergo chemical change due to air, groundwater and heat, giving rise to the other main variety of copper minerals - the oxidised ores. Commercially exploited deposits of copper ores are found in many parts of the world, frequently associated with mountain building processes. Deposits occur at many locations in the western cordillera of the Americas, mainly in the United States and Chile, and in areas of the North American plains like Michigan, Ontario, Quebec and Manitoba, at sites associated with the Pre-Cambrian shield. In Africa, the largest deposits are found in Zambia and Zaire, but copper is also mined in several other locations in Central and Southern Africa.

World map showing the location of copper producers (Deutches Kupfer Institut) Deposits also occur throughout Europe, which is still collectively a significant producer as may be seen from Figure 6. In Asia, the most extensive deposits are found in the CIS, with smaller deposits at widely scattered locations such as Indonesia, The Phillipines, India, and Turkey. Further medium sized deposits occur in Australia.

Figure 6 – Production of copper in each continent

55 The erosion of copper bearing rocks leads to the solution of copper in surface waters and its eventual re-deposition in seabeds or dry continental basins - with re-precipitation as sulphides, burial in sediments and folding. This is thought to have happened in what is now the African Copper Belt of Zambia and The Republic of Congo, where up to 20 metres thickness of ore occurs, with copper contents from 2% to over 4%. Frequently, copper deposits are associated with other common metals such as nickel and zinc. It is also common to find commercial quantities of precious metals such as silver and gold in the ore.

Extraction Modern methods of extraction allow economic leaching and electrowinning of copper from low grade ores and extraction techniques are continuously being refined and developed to achieve the most efficient removal of copper from a wide variety of ores from sources around the globe. The techniques for extraction of copper from oxidised ores are quite different from those employed for the sulphide ores. The oxidised ores, consisting of the silicates, carbonates and sulphates, are treated by several methods, all involving some form of leaching of the crushed ore with sulphuric acid to produce impure solutions of copper sulphate. If these leach solutions are very weak they are agitated with copper chelating agents dissolved in a paraffin base. The copper loaded solvent is then stripped of its copper by contacting with a strong sulphuric acid, producing a concentrated copper sulphate solution which is used as an electrolyte for electrowinning by the deposition of metallic copper on copper cathodes. This bypasses the fire-refining stage of conventional extraction.

Copper cathodes being lifted out of the electrolyte at the refinery (Deutches Kupfer Institut) Sulphide ores are first mechanically crushed and ground so that nearly all copper mineral particles are freed from the rock or 'gangue'. Flotation by the injection of air and violent agitation is carried out with the pulverised ore held in suspension in water, to which surface- active agents have been added. The sulphide minerals are continuously drawn off from the surface and dewatered to produce copper sulphide concentrate, which is further treated in one of two ways.

56 Controlled roasting is a process in which the sulphides are burnt in air to give a product of copper sulphates and oxides suitable for acid leaching as described earlier. The other method, matte smelting, is the most important for the extraction of copper from sulphides. There are several methods of smelting mattes (copper-iron sulphide and oxide slag) by the melting of concentrate at about 1200°C. The molten matte is then turned into 'blister-copper' by oxidation in a furnace. Finally, anodes (in what is known as tough pitch copper) for electrolytic refining are produced in a furnace in which sulphur is burned off with air blown through tuyeres, after which excess oxygen is removed. Continuous smelting and converting processes or flash smelting are now used to reduce costs and improve efficiency. Oxygen enrichment of the combustion air in the smelting process gives similar benefits. Microbiology can be utilised to recover copper from the spoil heaps of old mines, which frequently contain a small amount of insoluble copper sulphide. The bacterium Thiobacillus Oxidans converts this to soluble copper sulphate, which is leached out and electrolysed to recover the copper. The flowsheet shows simply the traditional mechanical and thermal refining processes for extraction of copper together with the more recent chemical solvent extraction technique.

Figure 7 – Flowsheet for primary copper production

The majority of high purity copper cathodes made in a refinery are bundled for transport to a copper rod mill where they are melted in a continuous shaft furnace and cast and hot rolled to make high conductivity copper rod of around 9mm diameter. This is passed to the wire mills for drawing to finished size.

57 Section 7 - Standards, Compositions and Properties (More comprehensive coverage of this topic is in CDA Publication No120 'Copper and Copper Alloys - Compositions, Applications and Properties'[35])

A Variety of Standards Coppers and copper alloys are specified in a very wide variety of ways by many different organisations. The British Standards that have been used since the old standards in Imperial units were metricated in 1969 are now being withdrawn and replaced by new ones after agreement across Europe. The corresponding European documents issued by other member countries will also be replaced by the common specifications. Other specifications used in the UK include many company specifications and those for defence procurement such as the NES (& DGS) specifications for Naval materials and the DTD documents. American specifications, mainly the ASTM standards that use the UNS (ex CDA Inc.) material numbering system and the SAE specifications remain unaffected. American military specifications (MIL series) are being based on the ASTM specifications where possible but include more stringent requirements for inspection, testing and packaging.

The New BS EN Standards The new BS EN series of standards for copper and copper alloys offer a selection of materials to suit a very wide variety of end uses. They represent a consensus agreement on those most frequently ordered by consumers. Commencing in the late 1980s, drafting of European Standards for Copper and Copper Alloys became a major activity for national standards organisations and their industrial partners. Within CEN, the work is being done in Technical Committee TC/133 ‘Copper and Copper Alloys’ with good representation from members of the corresponding BSI Committee NFE/34. Because a large number of national preferences have needed to be taken into account against the background of a pan-European agreement to develop tight product standards, the new BS EN standards (the British implementation of European standards) are more complex than the historic BS standards. Furthermore, the BS EN standards tend to cover narrower fields than BS standards; hence there are more materials in the BS EN series than in the previous BS standards.

Withdrawal of old standards As the new standards are published they will be in conflict with the old British Standards. These will therefore be withdrawn, as will those of other European countries, leaving Europe with one harmonised series of standards published in each country but applicable across all. The majority of the ratified versions of the new standards, published or due during the period 1996-1998, caused, or will cause, withdrawal of conflicting national standards such as BS1400, the BS287x and the BS143x series. Materials popularly used from the previous BS standards will of course continue to be available but the new designations should be used. Compositions, properties, tolerances and other requirements will conform to the standard quoted.

58 Table 5 - BS EN Standards for Copper and Copper Alloys For an up-to-date version of this table showing BS EN numbers please see Table 1 – CDA Publication 120

BS EN number (*) Title Nearest Old BS Equivalent Unwrought products 1978 Copper cathodes 6017 1977 Copper drawing stock (wire rod) 6926 1976 Cast unwrought copper products 6017 1982 Ingots and castings 1400 1981 Master alloys - Rolled flat products 1652 Plate, sheet, strip and circles for general purposes 2870, 2875 1653 Plate, sheet and circles for boilers, pressure vessels 2870, 2875 and hot water storage units 1654 Strip for springs and connectors 2870 1172 Sheet and strip for building purposes 2870 1758 Strip for lead frames - (133/16) Hot dip tinned strip - (133/18) Electrolytically tinned strip - Tubes 12449 Seamless, round tubes for general purposes 2871 Pt.2 12451 Seamless, round tubes for heat exchangers 2871 Pt.3 1057 Seamless, round copper tubes for water and gas in 2871 Pt.1 sanitary and heating applications 12452 Rolled, finned, seamless tubes for heat exchangers - 12735 Seamless, round copper tubes for air conditioning - and refrigeration Part 1 : Tubes for piping systems Part 2 : Tubes for equipment (133/26) Seamless, round copper tubes for medical gases - 12450 Seamless, round copper capillary tubes - 133/29 Pre-insulated copper tubes - Tubes with solid covering Rod/bar, wire, profiles 12163 Rod for general purposes 2874 12164 Rod for free machining purposes 2874 12165 Wrought and unwrought forging stock 2872 12166 Wire for general purposes 2873 12167 Profiles and rectangular bar for general purposes 2874 12168 Hollow rod for free machining purposes - (133/52) Rod and wire for welding and braze welding 1453, 1845, 2901

59 Table 6 (continued)

BS EN number (*) Title Nearest Old BS Equivalent Electrical purposes (133/60) Copper plate, sheet and strip for electrical purposes 4608

(133/61) Seamless copper tubes for electrical purposes 1977

(133/62) Copper rod, bar and wire for general electrical 1433, 1432 purposes (133/63) Drawn round copper wire for the manufacture of 4109, 6811 electrical conductors (133/65) Products of high conductivity copper for electronic 3839 tubes, semiconductor devices and vacuum applications (133/66) Copper profiles for electrical purposes

Forgings and fittings 12420 Forgings 2872 1254 – Pt.1 to 5 Plumbing fittings 864

(*) When the BS EN number is not yet available the number is expressed as : -(Technical Committee Number / Work Item Number i.e. 133/xx)

Numbers and Titles of Standards Table 5 shows BS EN standards’ titles, categorised by product type and the BS standards that are replaced. During the standardisation process, at the stage of draft for public comment, an EN number is allocated. At this stage drafts are identified with the prefix ‘pr’. After successful formal vote, when the draft is approved for publication throughout Europe, the BS EN implementation uses the same number. This publication lists the BS EN numbers, even if still the provisional ‘prEN’ at publication. When the number is still not known, the Technical Committee 133 Work Item Number is given, i.e. 133/xx.

Product Forms As part of the standardisation process, uniform definitions have now been adopted for all product forms. This will result in some products having new terminology. As an example, the term ‘wire’ now includes all material made in coil form.

Material Designations Material Designations (individual copper and copper alloy identifications) are in two forms, symbol and number. As with many other existing European national standards, symbols are based on the ISO compositional system (e.g. CuZn37 is 63/37 brass). ISO and EN symbols may be identical but the detailed compositional limits are not always identical and cannot be assumed to refer to unique materials.

60 A new numbering system has therefore been developed to offer a more user- and computer- friendly alternative. The system is a 6-character, alpha-numeric series, beginning C for copper based material; the second letter indicates the product form as follows:- B Materials in ingot form for re-melting to produce cast products C Materials in the form of cast products F Filler materials for brazing and welding M Master alloys R Refined unwrought copper S Materials in the form of scrap W Materials in the form of wrought products X Non-standardised materials A three-digit number series in the 3rd, 4th and 5th places is used to designate each material and can range from 001 to 999; with numbers being allocated in preferred groups, each series being shown below. The sixth character, a letter, indicates the copper or alloy grouping as follows:-

Number series Letters Materials 000-099 A or B Copper 100-199 C or D Copper alloys, low alloyed (less than 5% alloying elements) 200-299 E or F Miscellaneous copper alloys (5% or more alloying elements) 300-349 G Copper – aluminium alloys 350-399 H Copper – nickel alloys 400-449 J Copper – nickel - zinc alloys 450-499 K Copper - tin alloys 500-599 L or M Copper – zinc alloys, binary 600-699 N or P Copper – zinc - lead alloys 700-799 R or S Copper – zinc alloys, complex

Material Condition (Temper)Designations Material condition (alternative term – Temper) designations are defined in BS EN 1173. In most product standards, materials are available in a choice of material conditions. Depending on the product standard there may be one or more mandatory properties associated with the particular material condition. For designation purposes the principle mandatory property for each material condition is identified by a letter, as follows:- A Elongation B Spring Bending Limit D As drawn, without specified mechanical properties GGrain size H Hardness (Brinell or Vickers) M As manufactured, without specified mechanical properties R Tensile strength Y 0.2% proof strength

61 Products can only be ordered to one material condition and not a combination. However, besides the designating property, other properties may be mandatory; check the standard document for full details. Normally three digits, but in a few instances four digits, follow the material condition designating letter, where appropriate, to indicate the value of the mandatory property with the possibility of a final character, ‘S’, for the stress relieved condition. Normally the value refers to a minimum for the property. Sometimes, as with grain size, it refers to a nominal mid-range value. Tables 6 to 13 in Publication No 120 show not only the existence of copper or copper alloys in particular standards but also the material conditions available as mandatory properties within those standards.

Castings For castings, properties are dependent on the casting process used. This is designated according to the system: GS sand casting GM permanent mould casting GZ centrifugal casting GC continuous casting GP pressure diecasting

Examples CW614N – R420 refers to wrought CuZn39Pb3 copper-zinc-lead alloy to be supplied to a minimum tensile strength of 420 N/mm2 CC750S - GS refers to sand cast CuZn33Pb2 copper-zinc duplex alloy Each product standard gives examples of the full ordering information required including quantity, product form, standard number, designation, condition, tolerances and packaging.

Typical Properties In Tables 6 to 13 of CDA Publication No 120, typical properties are usually shown as ranges. For materials available in both ‘soft’ condition, for example as forging stock, and ‘very hard’, for example as spring wire, then the ranges are very wide. Tables 14 to 18 show typical properties for ranges of brasses similar to those previously included in British Standards in order to give a closer idea of the range of properties available in each product form. It is vital that designers and purchasers consult with suppliers to clarify what property values and combinations are available to be best fit for purpose in the desired product form.

62 Section 8 - Historical

Copper through the ages

The Copper Age Pre-dynastic Egyptians knew copper very well and in hieroglyphs copper was represented by the ankh symbol also used to denote eternal life, an early appreciation of the lifetime cost- effectiveness of copper and its alloys. The Egyptians obtained most of their copper from the Red Sea Hills. The older civilisation based on the Euphrates also knew copper and well developed smelting techniques. The earliest known artefacts made from smelted metal were copper, and excavations at Catal Huyuk near Konya in Southern Anatolia, showing slags derived from the smelting of copper, have been dated to as early as 7,000 BC. Other civilisations in the Near and Middle East, Hindustan and China also developed the use of the vital metal. Homer referred to the metal as ‘Chalkos’; the Copper Age is therefore referred to as the Chalcolithic Age. Roman writings refer to copper as ‘aes Cyprium’ since so much of the metal then came from Cyprus.

The Bronze age There is evidence that early workers knew that the addition of quantities of tin to copper would result in a much harder substance. This alloy, bronze, was probably the first alloy made and found particular favour for cutting implements. Numerous finds have proved the use of both copper and bronze for many purposes before 3,000 BC. Some of the earliest bronzes known come from excavations at Sumer, and are of considerable antiquity. At first, the co-smelting of ores of copper and tin would have been either accidental or the outcome of early experimentation to find out what kinds of rock were capable of being smelted. The smelting of lead was known by 3,500 BC, and lead, tin and arsenic all appear as adventitious alloying elements in smelted copper from early dates. An appreciation of quality in bronze depending on the tin content emerged only slowly. Consistency of composition of bronzes dates back to about 2,500 BC at Sumer, with bronzes commonly containing 11 - 14% tin - reasonable evidence both of technological forethought and the appreciation of metallurgical and founding properties. Indications of bronze production as far back as 2,800 BC come from places as far apart as India, Mesopotamia and Egypt, and make a single origin for bronze smelting significantly further back in time a strong possibility. Trade by land and sea, and the succession of cultures and empires, had dispersed knowledge of the copper-based metals slowly but surely throughout the Old World. By 1,500 BC it had spread across Europe and North Africa to the British Isles, and in other directions as far as India and China. Copper, bronze, copper-arsenic, leaded copper, leaded bronze and arsenical tin bronzes were all known by this date in most parts of the Old World. ‘Oetzti’, the 5,000-year-old mummified man found recently high in the Alps on the Italian- Austrian border was found with many implements including an excellent arsenical copper axe. It seems that he was probably a coppersmith himself, since his hair had high concentrations of copper and arsenic, which could probably have come from no other source. Alloys containing zinc were also emerging at this time, from Cyprus and Palestine, though the alloying is believed to have been natural in origin, due to the local ore containing some smeltable zinc minerals. Alloys similar to modern gunmetals were being cast before 1,000 BC,

63 though the proportions of copper, tin, zinc and lead were not well established. Following the emergence of true brasses in Egypt in the first century BC, possibly from Palestine, the industrious and methodical Romans rapidly consolidated the knowledge and usage of copper, bronzes, brasses and gunmetals. Bell founding originated in China before 1,000 BC and in time Chinese bell design attained a high degree of technical sophistication. The technology spread eventually through Asia and Europe to Britain, where early evidence of bell making has been dated to around 1,000 AD, through excavation of a bell casting pit at Winchester. Several important books were written during the Middle Ages concerning the extraction, smelting, casting and forging of copper. These established that the casting and working of copper and its alloys had its origins in craft traditions and practices that had developed over several thousand years. How much of this was originally handed down in writing is not known, since it is only from medieval times that the written tradition in technology is unbroken. It is through the Christian monastic and Islamic cultural traditions that detailed accounts of these early technologies have survived. The writings of the monk Theophilus in the 11th Century and of Georgius Agricola and Johannes Mathesius in the 16th Century, all describe in detail the metal producing technologies of their day. Often these had changed little for centuries. The output from the Bronze Age mines was considerable - an assessment based on old mine maps and studies of prehistoric workings at Mitterberg in the Austrian Alps indicated that about 20,000 tons of black copper had been produced there over the period of the Bronze Age. Black copper was the usual product of ancient smelting and contained about 98% copper. It was traded as flat cakes weighing a few kilograms for later refining to purer copper by ‘poling’. Significant engineering uses had been found for copper as early as 2,750 BC, when it was being used at Abusir in Egypt for piping water. Copper and bronze were employed for the making of mirrors by most of the Mediterranean civilisations of the Bronze Age period. The obliteration of Carthage by the Romans has obscured developments in Northern Africa at that time. It is only quite recently that evidence of the considerable engineering skills of the Carthaginians has emerged, including the earliest known use of gear wheels, cast in bronze. Bronze was used in many of the artefacts of every day Roman life - cutlery, needles, jewellery, containers, ornaments, coinage, knives, razors, tools, musical instruments and weapons of war. This pattern of use tended to be repeated wherever the smelting of bronze and copper was introduced, though necessarily on different time scales. The New World and Africa lagged in these developments by 3,000 - 3,500 years because of the distance and isolation of these areas from the trade routes that loosely bound the ancient world.

Mining The oldest methods for removing rock from underground mines were the sledgehammer and wedge and the equally ancient technique of fire setting. In the latter case a fire set up against a rock face would produce thermal stresses - the rock would either crumble naturally or could be shattered by water quenching. It was some time after the Islamic world introduced blasting powders to Europe in the 13th century, from China, that explosives were first used specifically for mining. Today the old mining techniques have been replaced almost entirely by blasting with modern safe explosives, and the use of heavy duty mechanical cutting equipment, where the rock is soft enough to merit such treatment.

Middle Ages and beyond The invention of printing increased the demand for copper because of the ease with which copper sheets could be engraved for use as printing plates. In Germany, playing card designs were engraved on copper as far back as 1430. Copper plates have long been adopted as the best 64 means of engraving maps. The first known maps printed from copper plates are two Italian editions, dated 1472, by the geographer Ptolemy. H.M. Ordnance Survey, continuously since 1801 and the Admiralty both use copper plates for printing maps and charts. Copper has other important uses at sea, as copper sheathing of the hulls of wooden ships was introduced in the middle of the 18th century. This was intended to protect the wood against shipworm when in warm seas. It was found that it also kept the hulls free of barnacles and other marine growth, preventing the consequent severe drag that slowed the ships. This enabled Nelson’s ships to spend many months on blockade duty and still be swift when battles commenced. Now, copper-nickel cladding can be applied to wood, polymer or steel hulls to prevent the fouling of ships operating at higher speeds. In the early 18th century Swansea was becoming a major copper centre and by 1860 was smelting about 90% of the world’s output. At first, Swansea obtained most of its ore from many mines in Cornwall and also Anglesey. By 1900, Morwelham on the River Tamar was the world’s largest copper port and Parys Mountain near Amlych in Anglesey was the world’s largest copper mine. Then, as the industry developed and other sources were found abroad, almost all ores were imported. The smelting of the ores subsequently moved nearer the sources of supply. During the 19th century Birmingham became the main centre for fabricating non-ferrous metals in Britain, a position that is still held. Many major developments in the copper industry emanated from the Birmingham area. • In 1832 George Muntz patented a process for the manufacture of brass consisting of 60% copper and 40% zinc. • A method for the application of electrolysis to the refining of crude copper was invented by a Birmingham silver-plater, James Elkington, in 1864 and led to the establishment of the first such plant in Swansea in 1869. • Towards the end of the 19th century Alexander Dick introduced the fundamental new process of hot extrusion for making brass rod from billet. By far the greatest extension in the use of copper resulted from Michael Faraday’s discovery of electromagnetic induction in 1831 and the subsequent development of the electrical engineering industry. Copper has the highest conductivity of heat and electricity per unit volume of any known substance except silver, which is only slightly superior in this respect. Because the conductivity of copper is dependent on its purity, extensive use is made of copper in its unalloyed form. Today about half of the world’s production of copper is for electrical requirements. It is now produced in continuous vertical melting furnaces that supply a constant stream of molten copper for casting between a water cooled grooved copper alloy wheel and a steel belt to give a section that is passed directly in to a tandem hot rolling mill. At the end of the line, cool, clean copper rod that may be between 6 and 25mm diameter is coiled to pack sizes to suit wire mill needs. Redrawing to size and continuous annealing gives the cheap, good quality wire that is now used in large quantities.

Brass Brass has been made for almost as many centuries as copper but has only in the last millennium been appreciated as an engineering alloy. Initially, bronze was easier to make using native copper and tin and was ideal for the manufacture of utensils. While tin was readily available for

65 the manufacture of bronze, brass was little used except where its golden colour was required. The Greeks knew brass as ‘oreichalcos’([36]), a brilliant and white copper. Several Roman writers refer to brass, calling it ‘Aurichalum’ ([37]). It was used for the production of sesterces and many Romans also liked it especially for the production of golden coloured helmets ([38]). They used grades containing from 11 to 28 per cent of zinc to obtain decorative colours for all types of ornamental jewellery. For the most ornate work the metal had to be very ductile and the composition preferred was 18%, nearly that of the 80/20 gilding metal still in demand. Before the 18th century, zinc metal could not be made since it melts at 420°C and boils at about 950°C, below the temperature needed to reduce zinc oxide with charcoal. In the absence of native zinc it was necessary to make brass by mixing ground smithsonite ore (calamine) with copper and heating the mixture in a crucible. The heat was sufficient to reduce the ore to metallic state but not melt the copper. The vapour from the zinc permeated the copper to form brass, which could then be melted to give a uniform alloy. In Mediaeval times there was still no source of pure zinc. When Swansea, in South Wales, was effectively the centre of the world’s copper industry, brass was made from calamine found in the Mendip hills in Somerset. Brass was popular for church monuments, thin plates being let in to stone floors and inscribed to commemorate the dead. These usually contained 23-29% of zinc, frequently with small quantities of lead and tin as well. On occasions, some were recycled by being turned over and re-cut. One of the principal industrial users of brass was the woollen trade, on which prosperity depended prior to the industrial revolution. In Shakespearean times, one company had a monopoly on the making of brass wire in England. This caused significant quantities to be smuggled in from mainland Europe. Later the pin trade became very important, about 15-20% of zinc was usual with low lead and tin to permit trouble-free cold working to size. Because of its ease of manufacture, machining and corrosion resistance, brass also became the standard alloy from which were made all accurate instruments such as clocks, watches and navigational aids. The invention by Harrison of the chronometer in 1761 depended on the use of brass for the manufacture of an accurate timekeeper that won him a prize of £20,000. There are many examples of clocks from the 17th and 18th centuries still in good working order. With the coming of the industrial revolution, the production of brass became even more important. In 1738, William Champion was able to take out a patent for the production of zinc by distillation from calamine and charcoal. This gave great impetus to brass production in Bristol. Wire was initially produced by hand drawing and plate by stamp mills. Although the first rolling mill in Swansea was installed at Dockwra in 1697, it was not until the mid-19th century that powerful rolling mills were generally introduced. The Dockwra works specialised in the manufacture of brass pins, the starting stock being a plate weighing about 30kg. This was cut in to strips, stretched on a water-powered rolling mill and given periodic interstage anneals until suitable for wiredrawing. With the invention of 60/40 brass by Muntz in 1832 it became possible to make cheap, hot workable brass plates. These supplanted the use of copper for the sheathing of wooden ships to prevent biofouling and worm attack. With improvements in water communications, the centre of the trade moved to Birmingham to be nearer to fuel supplies and to facilitate central distribution round the country. With the invention of the extrusion press in 1894, Alexander Dick revolutionised the production of good quality cheap rods. Subsequent developments in production technology, mentioned in many of the references given, have kept pace with customers’ demands for better, consistent quality in 66 larger quantities. The brass now is cast to extrusion billet form in three-strand horizontal continuous casting machines, cut to length, reheated and extruded in modern presses designed to give high quality and minimum wastage. Subsequent straightening, drawing, annealing, cutting to length, pointing and inspection is carried out under approved quality management schemes that ensure that material is supplied as ordered.

The Outlook for Copper The number of possible new copper alloys is endless, and research is constantly in progress to find materials with superior properties. Some alloying combinations have as yet proved impossible to make because of the earth's gravity. For this reason experimental work on new alloys has been undertaken during Skylab missions to take advantage of the weightless conditions in space. Copper or copper oxide, when contained in polyurethane plastic foams, significantly reduces the evolution of deadly hydrogen cyanide gas when such plastics are burnt. Some copper alloys have been developed which display a phenomenon known as Shape Memory Effect. These alloys find application in, for example, radiator mechanisms due to their capacity to change from one shape to another upon an alteration of temperature. New production methods have enabled the development by the International Copper Association of an enhanced efficiency car radiator. This has been achieved with the use of copper finstock rolled to much thinner gauge in modern mills, tubing made from precision strip by either high-frequency or laser welding and the use of new soldering/brazing techniques.

Table 6 - Cuprobraze vs brazed aluminium for radiators

CuproBraze III Brazed Same air pressure and coolant Radiator Core Aluminium pressure drop, smaller and lighter Header Width, mm 432 395 Tube Length, mm 550 505 Fin Thickness, mm 0.114 0.038 Tube Wall Thickness, mm 0.381 0.102 Coolant Pressure Drop, kPa 4.75 4.75 Air Pressure Drop, kPa 0.307 0.307 Dry Core Weight, kg 1.67 1.56 Wet Core Weight, kg 2.04 1.89

The use of copper as a roofing material will continue to grow. In many countries it is well accepted as a standard material needing only basic support structures for its low weight. The colour of the patina developed is much appreciated and the long maintenance-free lifetime much valued. Until recently the low lifetime cost had not been quantified, but now that authoritative figures are available it is being appreciated as much as an economic roofing material as for its looks. Copper has long been closely linked with the generation, transmission and utilisation of electricity. Now copper is not only one of the constituents in the new range of brittle superconductors but continues to provide the matrix material in which the superconductors are embedded. However, until superconductor developments ensure that the materials maintain their 67 low resistivity under working conditions, copper will remain economical and pre-eminent when fields of high magnetic flux are needed. In other electrical and electronic applications, requirements for copper will remain paramount. Increasing demands are being made by new technologies and the precautions needed to guard life safety and sensitive equipment from voltage and radiation effects. Better design of power circuits has become essential, with full consideration being given to allowing for energy efficiency, reliability assurance, prevention of new power quality problems and earthing fit for continuos current situations over a long installed lifetime. For message cables copper continues to be extremely effective in this Information Age. Extensive local area computer networks and telephone lines using ADSL (Asymetric Digital Subscriber Lines) technology to buildings now rely on high quality copper wires. Twisted pairs of conductors made to the Cat 5 specifications are now normal. The development and introduction of Cat 6, followed by Cat 7, will ensure that requirements for wide frequency bands will be satisfactorily and economically met. The uses of copper and its alloys and compounds will continue to change, as they have over thousands of years, to meet modern challenges. As an essential service material that is environmentally friendly, fully recyclable and fully sustainable, there is no viable alternative to copper - the 21st century metal.

68 Table 7 - Comparison of lifetime costs of typical roofing materials

Cost of Scrap Strip Supporting Cost to Typical Risk, % of Repair cost Total cost to Life Cycle Costs covering Value Covering Structure Replace Life repair cost per year year50 £/m2 £/m2 £/m2 £/m2 £/m2 Years per cycle £/m2 £/m2 Metal Pitched Copper, 55.15 10.99 3.00 54.00 47.16 87.5 6.5 0.04 111.31 half hard, 0.6mm Aluminium, 38.97 2.04 3.00 54.00 39.93 47 14 0.13 139.16 PVF2 colour coated, 0.7mm Lead code 5, 80.58 10.10 3.00 61.00 73.49 85 12 0.12 147.48 standing seams, 2.24mm Stainless steel, 52.87 6.28 3.00 54.00 49.59 97.5 6 0.03 108.59 terne coat, 439 grade, 0.4mm

Zinc, bright, 0.7mm 47.19 2.96 3.00 54.00 47.23 52 11 0.11 106.50

Non-metal Pitched

Tiles clay 33.97 0.00 4.00 61.00 37.97 60 10 0.06 98.14 Tiles concrete 24.68 0.00 4.00 61.00 28.68 50 10 0.06 117.24 Slate 68.61 0.00 4.00 61.00 72.61 100 10 0.07 133.24 Non-metal Flat

Asphalt 14.44 0.00 6.00 69.00 20.44 20 20 0.20 134.54 Bitumen felt 19.24 0.00 3.00 69.00 22.24 20 20 0.22 143.84 Source: – ECRC 1997.

69 Section 9 - Glossary, Reference and Further Information

Glossary Admiralty brass 70/30 brass with 1% tin added for extra corrosion resistance. Ageing Hardening an alloy by heating to a temperature where a precipitate forms from a super-saturated solid solution. Alpha brass Brass containing up to 36% of zinc is usually the single alpha phase with good cold working properties. Alpha-beta brass Brass containing over 36% of zinc or with other additions usually has two phases present, alpha and beta. Aluminium brass High copper brass with aluminium added for improved corrosion resistance. This is often used for condenser tubes. Aluminium bronze Copper-aluminium alloy with up to 13% of aluminium, usually also with other additions such as iron, manganese, nickel and/or silicon. Annealing Heating a metal in order to soften it after hardening by cold work or heat treatment. Anode copper Cast slabs of copper from the fire refining processes used as starters for electrolytic refining. Antlerite Copper sulphide ore. Arsenical copper Copper with arsenic additions used primarily for the manufacture of boiler fireboxes. Arsenical brass Brass with improved corrosion resistance containing arsenic, and frequently aluminium. ASM American Society for Metals. ASTM American Society for Testing and Materials, responsible for standards for metals. Azurite Copper carbonate ore. Backwardation LME term used when the price for cash copper commands a premium over the price for copper in three months time. Caused by temporary shortages in spot supplies. Beryllium copper Heat treatable copper-beryllium alloy of high strength and hardness. Beta brass A brass with very high zinc content may be mostly of beta structure. This is brittle and used only as a brazing filler alloy. Blue vitriol Copper sulphate. Bordeaux mixture Copper sulphate-lime mixture used as an adherent fungicide, especially for grapevines. Bornite Copper sulphide ore. Brass Copper-zinc alloy, also used to describe a memorial plate in a church, coinage or bearing block. Originally the term also covered copper-tin alloys now called bronzes. Also used to describe a tin-zinc spelter made for the manufacture of organ pipes. Brass lump Miners term for massive iron pyrites (fools’ gold). Brinell Hardness Standard hardness test using a specified load on a ball indenter (HB). Bronze Copper-tin alloy, term also loosely used for some other copper alloys.

70 Burgundy mixture Solution of copper sulphate and sodium carbonate developed in 1885 for the prevention of mildew and other diseases on grape vines. Busbars Copper bar or section used for carrying heavy currents. Busbars are generally rigid when compared to cables. Cadmium copper Copper with an addition of cadmium for good strength and wear resistance without significant loss of conductivity. Cathode copper Pure copper, the product of electrolytic refining supplied for melting for the manufacture of products. Cartridge brass 70/30 brass with good cold working properties. CEN European Standards Organisation. ‘EN’ standards are being adopted by all European countries. Chalcocite, copper Cuprous Sulphide ore. glance Chalcopyrite Copper sulphide ore. Chrysocolla Copper silicate ore. Cold working Deforming a metal at a temperature below that of recrystallisation so that the metal hardens. Continuous casting Production method for castings where the molten metal is continuously poured into an open mould while the solidified metal is slowly withdrawn and coiled or cut to length by flying saw. May be a vertical, sidecasting or upcasting process. Common brass 63/37 brass, standard cheap brass for cold working. It is now usually a 64/36 alloy to give improved corrosion resistance. Contango LME term applied when the price quoted for copper due for delivery in three months’ time is higher than that for cash copper on that day. This is the normal market situation, financing the interest charge. Copper bottom To sheath the bottom of ships with copper to prevent attack by the Toredo worm and prevent the attachment of biofouling including molluscs that slow the ship, first applied to British ships in 1761. Now used as a term of assurance of quality. Copper head A venomous snake, common in the United States of America Copper-nickel Covers copper alloys with less than 50% of nickel. Copper nose Slang term for inflamed nose, acne rosaaca, a bacterial infection treatable by antibiotics. Copper plate A polished plate of copper on which a design is engraved for printing. Copper wall Term used in sugar making to describe a double row of copper pans served by a common fire. Covellite Copper sulphide ore. Cuprite Copper oxide ore. Cupronickel Obsolete term for copper-nickel alloy. Deep drawing Forming hollow components by using a punch and die to give significant plastic deformation. Deoxidised copper Copper that has had deoxidiser added to reduce oxygen. Phosphorus is commonly added but other elements such as boron or magnesium may be used.

71 Dezincification Selective corrosion of the beta phase of duplex brass that leaves a copper residue under a ‘meringue’ of zinc oxide. DIN German National Standards Organisation DGS Director General Ships standards (obsolete, replaced by NES series) DHP Phosphorus deoxidised copper (previously known as ‘Dona’ copper). DLP Deoxidised copper, low phosphorus. DTD Directorate of Technical Development, military specifications. Drawing The process of pulling a metal through a die to reduce the cross section, usually performed cold. Ductility Ease with which material can be formed, for example by drawing, bending or rolling. The property is usually measured as elongation in a tensile test or by a bend or deep-drawability test. Duplex brass See alpha-beta brass. ECI European Copper Institute ETP Electrolytic tough pitch copper, standard high conductivity copper. Extrusion A hot working process in which a heated billet is forced to deform by being pushed through a die to produce a long product of uniform cross-section. Extrusion ratio The ratio of the cross-sectional area of a billet to that of the extruded product. Fire-refined copper Copper refined by melting and processing in an open hearth or rotary furnace. Galvanic compatibility When exposed to seawater, metals show a voltage dependent on the electrochemical series. Metals with near-similar voltages are compatible. Metals with differing voltages are likely to cause galvanic corrosion. German silver Obsolete term for nickel silver. Gilding metal Brass with high copper, usually 90/10 but sometimes 80/20. Gunmetal Copper-tin-zinc alloy. Heat treatable alloy An alloy capable of being strengthened by heat treatment, usually involving solution treatment followed by ageing (precipitation) treatment. High conductivity Standard form of copper with a purity giving a conductivity of 100% IACS copper or more. High tensile brass Brass with additions, typically iron, nickel, manganese and/or aluminium to give better strength and, usually, better corrosion resistance. Hipping A proprietary process for treating metals at very high pressures to compact them to produce good properties. Hot working Plastic deformation of a metal at a temperature high enough to promote recrystallisation, thus preventing cold working. IACS International annealed copper standard, a value for conductivity agreed in 1913 with copper being given the value of 100%, equivalent to 58MS/m or a mass resistivity of 0.15176 .g/m2. High conductivity copper is now frequently of 101.5% conductivity. ICA International Copper Association. INCRA International Copper Research Association, now superseded by ICA. ISO International Standards Organisation.

72 Leaded brass Usually a duplex brass with an addition of lead to give excellent machinability. LME London Metal Exchange. Malachite Copper carbonate ore. Manganese bronze Obsolete term for high tensile brass. MIL American Military specifications. Monel A nickel-copper alloy, usually 70/30, originally produced directly from a copper-nickel ore in Sudbury, Ontario. Muntz metal A 60/40 brass with good castability and hot working properties. Naval brass 60/40 brass with 1% tin added for extra corrosion resistance. Near net shape forming Forming a product near to final shape so that it needs little further finishing. NES Naval Engineering Standards. Nickel silver Copper-nickel-zinc alloy. Oxygen-free copper Copper melted and cast under controlled atmosphere to give low residual oxygen content. Oxygen-free electronic Oxygen free copper containing low residual volatile elements. copper Patina A protective film that develops on copper on exposure to the atmosphere. In most non-polluted environments it is basic copper carbonate but in industrial and urban areas it is mainly basic copper sulphate. Paris Green Copper-arsenic compound. Phosphor bronze A copper-tin phosphorous alloy, hard and strong. Poling Part of the old fire refining process that involves reducing the oxidised charge by submerging green wood in the liquid copper. Red Brass American term for copper-tin-zinc alloy (gunmetal). Rivet brass American term for common brass. Rockwell Hardness Standard American hardness test with several ranges of loads and indenters, HRB, HRC. SAE Society of Automotive Engineers (USA) Tough pitch copper Obsolete term for copper containing oxygen at about 0.03-0.07% which gave a level ‘set’ to the top of a wirebar when statically cast horizontally . Verdigris A strikingly green corrosion product that forms on copper in some circumstances, a complex basic copper acetate. Unlike a patina, it is water- soluble. Vickers Hardness Standard hardness test using a load on a diamond pyramid indenter (HV, VPN or VHN). Wrought product Component made by hot or cold deformation of a cast product, removing the original cast structure. Yellow brass American term for 67/33 brass.

73 Table 8 – Abbreviations for chemical elements used as alloying additions or found as impurities

Al Aluminium Ag Silver As Arsenic Au Gold B Boron Be Beryllium Bi Bismuth Cd Cadmium Co Cobalt Cr Chromium Fe Iron Mn Manganese Nb Niobium Ni Nickel P Phosphorus Pb Lead S Sulphur Si Silicon Sb Antimony Sn Tin Te Tellurium Zn Zinc Zr Zirconium

74 References and Further information • Contact the CDA Information Service for a full list of publications, Email: [email protected], Website: www.cda.org.uk, Online enquiry form: www.cda.org.uk/enquiry-form.htm. • CDA has a selection of wallcharts with teachers’ notes. • Rio Tinto London, 6, St James’s Square, London SW1Y 4LD have available material describing exploration for metals and the mining and extraction of copper. Other sources of information include • The Science Museum, London. • Local and University libraries.

Internet Many subjects are covered in good detail on the ‘Copper Page’, located at http://www.copper.org. This includes details of copper centre activities throughout the world, articles on many topics, illustrations and full access to the thousands of references accessible through the Copper Data Centre (CDC).

References 1. V Callcut, D Chapman, M Heathcote and R Parr, ‘Electrical Energy Efficiency’ CDA Publication No 116, 1997, 80pp. 2. ‘Copper for Busbars’, CDA Publication No 22 1984 64pp. 3. T Charlton, ‘Earthing Practice’, CDA Publication 119 1997, 69pp. 4. 'Electrical Design - a Good Practice Guide' CDA Publication No 123, December 1997, 76pp. 5. ‘Copper Alloy Bearings’, CDA Publication No 45, 1992, 26pp. 6. ‘Copper in Roofing’, CDA Publication No 32, 1985, 68pp. 7. ‘Architectural Brass’, CDA Publication No 89, 1981, 8pp. 8. V A Callcut, ‘Design for Production’, CDA Publication No 97, 1994, 64pp. 9. ‘Copper and Copper Alloy Castings’, CDA Publication No 42, 1991, 40pp. 10. US Government Geological Survey Report, 1997. 11. Scientific Counsel for Government Policy, Holland 12. ‘Copper in Plant, Animal and Human Nutrition’, CDA Book 35, 81pp. 13. ‘Copper and Human Health’ CDA Publication No 34 10pp 1985. 14. ‘Which Metals are Essential for Human Health? R A Goyer, International Council on Metals and the Environment Newsletter Vol 5 No 2, 1997, p5. 15. ‘Copper in Farming’, CDA Book No 2, 1971, 11pp. 16. ‘Uses of Copper Compounds’ CDA Technical Note TN11, 1974, 11pp. (out of print) 17. see ref 2 18. ‘High Conductivity Coppers- Properties and Applications’ CDA Book No 122, 1997, 32pp. 75 19. ‘Aluminium Bronze – Essential for Industry’ CDA Publication No 86, 1998, 8pp. 20. ‘Aluminium Bronze Corrosion Resistance Guide’, CDA Publication No 80, 1981, 28pp. 21. ‘Welding Aluminium Bronzes’ CDA Publication No 85, 1980, 7pp. 22. ‘Aluminium Bronze Alloys – Technical Data’, CDA Publication No 82, 1981, 93pp. 23. ‘Design in Brass’, CDA Publication No 133, 1998, 8pp. 24. V A Callcut, ‘The Brasses – Design Compendium’, CDA Publication No 117, 1996, 68pp. 25. Hawke Cable Glands, quoted in ‘Design in Brass’, CDA publication No 133,1998, 8pp. 26. ‘Copper-Nickel Alloys’, CDA Publication No 30, 1982, 22pp. 27. ‘Copper-Nickel Alloys – Technical Data’, CDA Publication No 31, 1982, 20pp. 28. ‘Materials for Seawater Systems’, CDA Publication No 38, 1986, 10pp. 29. ‘Copper-Nickel Cladding for Offshore Structures’, CDA Publication No 37, 1986, 10pp. 30. ‘Copper-Nickel Cladding on Ships and Boat Hulls’, CDA Publication No 36, 1985, 12pp. 31. See ref 7. 32. ‘Machining Brass, Copper and Copper Alloys’, CDA Publication No 44, 1992, 66pp. 33. L. Brown, ‘Joining of Copper and Copper Alloys’, CDA Publication No 98, 1994, 44pp. 34. ‘Clear Protective Coatings for Copper and Copper Alloys’, CDA Publication No 41, 1991, 16p. 35. ‘Coppers and Copper Alloys - Composition and Properties’, CDA Publication No 120, 1997, 22pp 36. B Webster Smith, ‘Sixty Centuries of Copper’, CDA Publication No 69, Hutchinson, London 1965. (out of print) 37. De Re Metallica, Geogius Agricola, 1556, translated by H C and L H Hoover, 1950, Dover Publications Inc. New York. 38. G W Preston, ‘Copper through the Ages’, CDA Publication No 3, 62pp 1934, quoting Gowland, ‘Copper and its Alloys in Early Times’, J Inst. Met 7, (1912) pp 35-36.

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