GENERAL SUGGESTIONS for GOOD FOUNDRY PRACTICE Control of Melting Atmospheres 4

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GENERAL SUGGESTIONS FOR GOOD FOUNDRY PRACTICE Control of Melting Atmospheres 4. Another rapid qualitative test may be accomplished When melting copper-base alloys in fuel-fired furnaces, by pushing back the slag or dross on the surface of proper control of the analysis of the products of combus- the metal just after it has become completely mol- tion is very important. Without going into the theory of ten and observing the appearance of the exposed gases in metals, it can be stated that the copper-base al- surface. If the surface stays mirror bright (similar loys should be melted under an oxidizing atmosphere. The to a pool of mercury), the atmosphere is highly foundryman has several methods for determining the type reducing. If the surface becomes cloudy or filmy of atmosphere which surrounds the metal during the melt- immediately, the atmosphere is too highly oxidizing operation. These tests are: ing. The proper atmosphere is one that causes the exposed surface to become cloudy or film over in 1. Visual—a short, sharp flame with a slight green three to five seconds. This test should be done at tinge around the outer edge usually indicates an a temperature prior to the vaporization of the zinc oxidizing atmosphere. However, green flames are as it will completely mask the observation of the not always oxidizing; a long, lazy green flame has surface. been found to be reducing. For this reason, visual Even though the flame is oxidizing at the point where determination, unless done by a highly skilled op- it leaves the furnace and comes in contact with secondary erator, is often inaccurate. A yellow, yellowish-red air, this does not necessarily indicate that it is oxidizing smoky flame is an indication of a reducing atmo- over the surface of the metal, although the possibilities are sphere. in its favor. If, however, the flame is reducing when leaving 2. Orsat or other gas testing equipment gives an ac- the furnace, it certainly will be reducing over the surface curate analysis of the hydrogen, carbon dioxide, of the metal. carbon monoxide and oxygen in the sample, but the difficulty lies in getting the proper sample. The Fracture Tests time necessary to run the test is also a handicap, An indirect, though a most important method of de- for the atmosphere may change considerably dur- termining melt quality of the tin bronzes, high lead tin ing the period, and any changes made in burner bronzes and the red brasses, is by the fracture of test pieces controls might make results erroneous. or actual production castings. The physical appearance 3. Probably the most accurate qualitative method is of a fractured section is related to melt conditions, pour- the zinc test, due to its simplicity, practicability ing temperature, mold conditions and gating and risering and speed. A small, clean, cold piece of virgin zinc practices. If the latter two variables could be held relatively is held in the flame, just above the liquid bath, for constant, then the fractured section could be correlated about five seconds. If the zinc turns black, the at- with gas content and pouring temperatures. The follow- mosphere is highly reducing. If it turns straw yel- ing is a procedure for acquainting the foundryman in the low to light gray, the atmosphere is slightly reduc- interpretation of fractures. ing. If it does not change color, the atmosphere is Each of the alloys in question should be melted under oxidizing. Its very simplicity should permit a test oxidizing conditions and brought up to an extremely high of every furnace immediately after the metal is temperature and poured into some type of bar or one of the molten, with correction of the flame, if necessary. regular production castings that can be readily fractured.

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4-1 The metal should be cooled to 2300°F and the bar or cast- necessity of extensive laboratory facilities that would be ing poured. Another bar or casting is poured after every necessary in the use of virgin metals. Possibly the great- 100°F drop in temperature, until the castings are about est advantage of using ingot alloys over virgin metals is to misrun. This same procedure should then be repeated economics. Most alloys are sold at a price below the virgin with the metal melted under reducing conditions. metal component prices. It is most important that the fractured sections be examined immediately after the casting or test pieces are Segregation of Alloys broken; otherwise they have a tendency to tarnish after As more and more copper-base alloy castings are sold to exposure to the air and are apt to be misleading. It is pos- meet definite chemical and physical specifications, the pro- sible to determine the best pouring temperature range, as duction of such castings utilizing foreign scrap* becomes well as to distinguish between the fracture of castings that increasingly more difficult. Contamination of scrap with have been melted under oxidizing conditions, as against elements that cause leakers, unsoundness and bad finish is those melted under reducing conditions. increasing, and the use of this contaminated material to Any attempt to describe to the foundryman the make castings of high quality cannot be justified under color or texture of the fracture that he should look for any circumstances in a well-run foundry. would be confusing. Only with experience and close For example, at one time, most sleeve bearings were observation can he be taught; but once he gets the knack made from the copper-tin-lead alloys; however, today, of interpreting fractures, he has a tool for a quick test of sleeve bearings are also being made from aluminum metal quality. bronzes, manganese bronzes, silicon bronzes and cast- iron or steel-backed babbitt lined bushings. Usually, the Brass and Bronze Ingots Versus Virgin Metals surfaces of these scrap castings are dirty or covered with H. Kramer & Co.’s quality controlled specification brass grease and sometimes painted, which makes them virtu- and bronze ingot has many advantages, compared to the ally impossible to differentiate without the aid of complete compounding of virgin metals, to attain the same alloy. laboratory equipment and experienced personnel. H. Kramer & Co. guarantees that its alloy ingot is always Brass and bronze scrap returning to the market today within the chemical composition which is specified, and is composed of many complex alloys and alloy assemblies that with normal foundry practice, it will meet the me- that cannot be thoroughly sorted and separated to be of chanical and physical properties desired. However, when any value in the production of castings. Such elements as compounding virgin metals to make the same alloy, it is aluminum, silicon, manganese, titanium, cadmium, mag- necessary to weigh each item separately, and any mistakes nesium, chromium, and others are being alloyed with cop- in weighing will result in an alloy that is outside of the per and are now getting into scrap and are almost impos- composition limits desired. In many cases, when using sible to separate by economical sorting procedures. virgin metals, it usually becomes necessary to add harden- Brass and bronze valves, which at one time were nor- ers, which becomes an added cost. mally made from copper-tin-lead-zinc alloys, are now It is well known that ingot metal is less sensitive to returning in scrap from many different types of alloys: gas absorption than the melting of the individual com- yellow brass, tin bronze, aluminum bronze, manganese ponents. When using virgin metals, the original melt is bronze, silicon brass and silicon bronze, nickel alloys and frequently heterogeneous and it may be necessary to pig, ferrous alloys. Valve stems are being made out of cast and analyze and remelt to get homogeneity, which will add *Foreign scrap is that purchased from sources outside the foundry (such as scrap dealers). extra laboratory and melting costs. Domestic scrap is that generated in the foundry (gates, risers, reject castings and turnings) that Guaranteed composition of ingot metal obviates the may be used without difficulty if kept segregated, clean and dry.

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4-2 wrought products which may be manganese bronze, alu- while in the molten state, make the necessary metal additions minum bronze, Tombasil and various copper-nickel or to adjust to the desired composition, deoxidize the heat as may nickel-copper alloys. The same holds true of discs and be necessary and then cast the metal into ingot. Sample ingots, seats in the valve. These are extremely difficult to hand per-iodically set aside during the casting cycle, are drilled to ob- sort in any economical fashion. Radiators, in addition to tain a final chemical analysis. having a great percentage of non-metallic accretions have The entire cycle is then supplemented with physical significant amounts of iron adhering, both externally and and mechanical tests and metallographic examination. A internally. In addition, radiator fins made of aluminum high quality product is thus assured. and stainless steel are also appearing on the market. It Not only is the metal coming into the foundry consid- is virtually impossible to sort yellow brass so that it is ered raw materials, but the foundry returns and domestic entirely free of aluminum and silicon. Condenser tubes, scrap must also be considered raw material. which at one time might have been normally copper- Foundry return scrap must be very closely segregated zinc alloys, with small additions of tin, are returning in by alloy in order to avoid contamination, as most of the a myraid of alloys, containing aluminum, arsenic or an- alloy groups are incompatible with one another. For ex- timony. Aluminum bronze, many variations of copper- ample, if aluminum bronze, manganese bronze or silicon nickel, monel and stainless steel alloys are also used for bronze is mixed with red brass, it will reduce the mechan- condenser tubes. ical properties and pressure tightness to such a degree that The above examples merely illustrate in a small way the red brass castings would be rendered almost useless. the types of impurities that can be involved in the usage Conversely, if the aluminum bronzes, manganese bronzes of scrap for the making of castings. It may be concluded or silicon bronzes are contaminated with any of the leaded that it would be expensive and dangerous in the long run bronzes, serious reduction in mechanical properties results. to use foreign scrap in the production of copper-base alloy Careful housekeeping of charge make-up area, cleaning castings. room, and machine shop is a must if contamination is to Only a competent ingot manufacturer can pro- be kept to the minimum. duce quality ingot from such complex raw materials. As an example of one class of copper alloy being con- Certainly the foundry is completely lacking in the es- taminated with another, small pieces of aluminum bronze sential facilities to substitute the complex assortment and silicon bronze were intentionally added to heats of a of foreign scrap for quality ingot. It is both uneco- high lead in bronze, 80-10-10. nomical and hazardous for the foundry to use scrap As shown in Figures 1, 3, and 4 aluminum and sili- because it is not enough simply to sort and grade the con cause considerable unsoundness in sand castings made raw material and later select certain grades to remelt. from the bearing alloys. This unsoundness, in turn, causes On the contrary, the production of quality metal re- a considerable weakening of the casting, as illustrated by quires scientifically controlled smelting and refining the listed tensile properties (see page 4-4). Further weak- processes, under the supervision of trained metallur- ening results if the bearing should become overheated, gists and chemists. which may result in cracking and subsequent failure of the These refining processes are not commercially feasible bearing. in small furnaces, but require large furnaces, handling Aluminum and silicon also form their oxides readily quantities of 100,000 pounds or more. in the molten alloy. These oxides then become entrapped The usual practice is to melt a large tonnage at one time, re- in the castings and are considerably harder than the base fine the heat by the use of proper fluxes and slag-forming mate- metal. If these hard particles are on the bearing surface, rials under the strictest metallurgical controls, analyze the heat considerable damage to the shaft may occur.

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4-3 The introduction of small amounts of aluminum and/ the properties and pressure tightness. The Society of Auto- or silicon will completely destroy the physical properties of motive Engineers, American Society for Testing Materials the 80-10-10 and red brass type alloys. The amount of alu- and the brass and bronze ingot manufacturing industry minum and silicon necessary to seriously affect the prop- have set limits of 0.005 per cent on both silicon and alu- erties has not actually been determined, but it is believed minum for this alloy. that as low as 0.01 per cent of either will markedly reduce

CHEMICAL ANALYSIS A.S.T.M. SPEC. 80-10-10 No. (a) Silicon 80-10-10 No. (b) Alum. 80-10-10 No. (c) Copper 78.00 - 82.00 80.01 80.36 79.98 Tin 9.00 - 11.00 9.24 8.90 9.10 Lead 8.00 - 11.00 9.63 9.59 9.85 Zinc .75 Max. .43 .46 .50 Iron .15 Max. .03 .02 .04 Antimony .50 Max. .19 .19 .18 Nickel .75 Max. .29 .29 .30 Aluminum .005 Max. None None .03 Silicon .005 Max. None .033 None

TENSILE STRENGTH RESULTS Tensile Strength p.s.i. 34 ,000 Min. 34,000 12,650 20,050 Yield Strength p.s.i. 16,300 11,700 17,000 % Elongation in 2” 22.0 26.0 3.0 4.0 Fracture of Test Bar Blue-gray center flecked 95% Orange. 40% Orange. with yellow specks. Fine. Very coarse dendrites. Very coarse dendrites.

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4-4 a b c Fig. 1 Fig. 2 Fracture Characteristics of Bearing Alloy with Silicon and 80-10-10 contaminated with various amounts of Silicon Aluminum. Upper left — No Silicon Description of Fractures: Lower left — 0.03% Silicon Upper right — 0.01% Silicon a. Normal 80-10-10, Blue-gray color with slight yellow specks Lower right — 0.10% Silicon in center portion. Structure is dense. b. 80-10-10 with 0.03% Silicon; blue gray rim 1/8” thick. Cen- ter portion is orange. Structure is dendritic and very coarse. c. 80-10-10 with 0.03% Aluminum, Blue-gray rim 1/8” thick. Center portion is mottled orange and gray color. Structure is dendritic and very coarse.

Fig. 3 Fig. 4 Photo-micrograph of regular 80-10-10 showing normal distri- Photomicrograph of 80-10-10 Contaminated with either Alumi- bution of the lead particles in the copper-tin alloy matrix. Mag- num or Silicon. The gray islands are the lead particles. The dark nification X100. Not etched. connected channels are interdentric porosity. This structure is typical of that obtained in the leaded bronzes when contaminated with either Aluminum or Silicon. Magnification X100.

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4-5 RED BRASSES AND TIN BRONZES The basic metallurgy and foundry practice for tin bronzes, at a temperature only slightly above what is necessary leaded tin bronzes and red brasses are very similar and will for pouring, in a slightly oxidizing atmosphere (see pg. be discussed as a single group. 4-1 Control of Melting Atmosphere). For large intricate castings, it is beneficial to superheat the metal 200F to General Metallurgy 300F degrees and allow to air cool to reduce gas content. Tin bronzes are alloys of copper and tin, with or without Metal should be poured as soon as it is ready. zinc, with nickel additions when used in the manufacture 15% Phosphor Copper is used as a deoxidizer for of gears. Tin bronzes have excellent wear and corrosion this alloy group. The recommended quantity is two to resistance. They are used for valve and pump bodies, four ounces for alloys containing less than 8% Zinc, and steam fittings, paper machinery, piston rings, bearings and one to two ounces for those with higher Zinc content. impellers. An alloy of eighty percent copper and twenty Phosphor Copper can be stirred into the ladle or, in tilting percent tin is used for bells because of its exceptional tonal furnaces, it can be introduced into the qualities. stream after 20 to 25% of the ladle has been filled. Leaded tin bronzes have essentially the same Zinc additions made to replace Zinc lost during the applications as tin bronzes except for a small lead addition melting cycle may be made along with the Phosphor to improve machinability. Some leaded tin bronzes Copper. are used for bearings and bushings. The load carrying A pouring temperature between 1950F and 2250F capability of these alloys varies with the copper and tin is satisfactory for most castings, but those with extremely content. Lead, because it is insoluble, is finely dispersed thin walls may require temperatures at or above 2300F. in the base alloy, providing lubrication and embedability. Whatever the situation, temperatures should be kept Alloys in this group are used in machine tools, electrical as low as possible but still sufficient to avoid misruns machinery, railroad cars, diesel engines, gasoline engines or internal shrinkage. The lip of the ladle should be and in bearings where acid resistance is essential as close as possible to the sprue opening, keeping the Red brasses (and semi red brasses) are combinations sprue full and ensuring an uninterrupted stream. It is of copper, tin, lead and zinc that offer excellent strength, recommended that reliable calibrated pyrometers be corrosion resistance, machinability and foundry employed to help control pouring temperatures. characteristics at a relatively low cost, thus making This group of alloys solidifies over a wide range of them the most widely used of all copper based casting temperatures. Foundrymen must employ a variety of alloys. Most plumbing goods, valves and fittings, marine techniques; chills, insulated risers, hot-top compounds hardware, ornamental and statuary castings, pump bodies and gating practices, to insure proper directional and impellers, water meters and other general castings are solidification. A thorough study of each casting will reveal poured from this group of alloys. the best types and optimal locations for gates, risers and chills. Whenever possible, arrange the gating so that the Foundry Practice riser feeds directly from the gate and receives the last metal Any furnace type can be used to melt these alloys. Proper to enter the mold. precautions are indicated to insure safe and smooth Sand permeability can range from 25 for small, thin-walled operations. Gas fires furnaces must maintain proper castings to as much as 100 for large, heavy-wall ones. combustion. Usually, the most consistent results for Whatever the permeability requirements, moisture control these alloys are achieved by melted as rapidly as possible, is of paramount importance. Proper venting is also essen-

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4-6 tial to reduce pressure on the core and protect the casting where a low-cost alloy can be used. These alloys also have from gas buildup. Care must be exercised to prevent the good polishing and machining qualities and this, coupled core from becoming too hard to prevent cracked castings with their low cost, makes them attractive to the hardware and knockout difficulty. The yellow brass alloys are used and plumbing industries. mostly where their characteristic yellow color is desired or

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES 1. Melt rapidly under oxidizing atmosphere 2. Do not hold in furnace longer than necessary 3. Metal not to be heated more than 150°F melting temperature 4. Add zinc where required 5. Add appropriate amount of Phosphor Copper 6. Skim carefully and avoid vigorous stirring 7. Take accurate temperature readings 8. Pour at lowest temperature that will protect against misruns and internal shrinkage 9. Keep sprue full at all times 10. Provide adequate gates and risers 11. Maintain sand properties

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4-7 LEADED YELLOW BRASSES The yellow brass alloys are used mostly where their character- Due to the large amount of zinc present in the yellow istic yellow color is desired or where a low-cost alloy can be brasses, little or no deoxidation is required. However, to used. These alloys also have good polishing and machining improve the fluidity of these alloys, aluminum or phospho- qualities and this, coupled with their low cost, makes them rus is added. (Aluminum and phosphorus should never be attractive to the hardware and plumbing industries. used together). Phosphorus is used where the sections are thin and the casting is required to be pressure tight. Alu- General Metallurgy minum is used when there are no pressure requirements In general the strength of yellow brass increases as the cop- and a smooth surface appearance is desired. Zinc should per decreases. At the same time the ductility decreases. Tin, be added to replace that lost in melting. present up to 1.5 per cent, normally helps to increase the In general, a pouring temperature of approximately strength and hardness, while at the same time improves ma- 2050°F is adequate for most castings. Above this tempera- chinability and corrosion resistance. Lead, also added up to ture, zinc will flare profusely and may cause dirty castings. 4 per cent, improves machinability and polishing properties. However, if the sections are thin and the casting has no Yellow brasses are used principally in the hardware pressure requirements, a higher temperature may be used and plumbing industries. Specific examples are andirons, adding aluminum to control flaring. door knobs, escutcheons, band instruments, lamp fixtures, The gating practice for yellow brass is similar to that locks, ornamental parts, furniture hardware, plaques, of the red brasses. The sprue, gate and runner should be valves, faucets, ferrules, and fittings. slightly larger, to insure that the mold cavity fills as rapidly as possible to prevent any zinc oxide forming dirt or holes Foundry Practice on the surface of the casting. Vent the end of the casting to Any of the furnaces used for melting the copper base alloys insure relief of back pressure. may be used for melting the yellow brasses. Zinc losses may Generally, only small castings are made from yellow be encountered in open-flame furnaces. Even though the brass and fairly fine sands may be used. Sand should be dry yellow brass alloys are not as susceptible to gas pickup as the to prevent boiling action against mold faces causing drossy other copper-base alloys, it is recommended that melting be appearance on casting surfaces. carried out under a slightly oxidizing atmosphere.

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES 1. Melt rapidly and do not heat to more than 100°F higher than the desired pouring temperature. 2. Add zinc to replace that lost in melting. 3. Add 0.10 per cent to 0.30 per cent aluminum for castings not required to be pressure tight. Add 1 ounce of 15 per cent Phosphor Copper per hundred pounds of melt for castings required to be pressure tight. It is important to remember that phosphorus and aluminum are never to be used together. 4. Pour with as little turbulence as possible. 5. Sand should be kept dry, taking care to ram mold evenly. 6. Sprue, runner and gates should be of adequate size to fill mold cavity rapidly.

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4-8 MANGANESE BRONZES General Metallurgy consistently high mechanical properties, the composition Manganese bronze (or more correctly, high strength yellow must be closely regulated and controlled. Many elements brass) combines high tensile strength and yield strength are undesirable and affect the properties adversely, thus with relatively good corrosion resistance. This group of al- limiting the raw materials for the manufacture of the man- loys is basically copper and zinc to which various propor- ganese bronzes to only those of the highest purity. tions and combinations of aluminum, manangese, iron, Variations in the major alloying elements greatly af- tin and nickel are added. Lead is sometimes added to im- fect the mechanical properties obtainable from the man- prove machinability. ganese bronzes. The primary consideration when melting Aluminum is added in the range of 0.5 per cent to is to maintain the proper copper-zinc ratio. Zinc loss from 7.5 per cent and is the principal strengthener of the alloy remelting ingot and foundry returns must be addressed. group. Manganese varies from 0.2 to 4.0 per cent and iron Variation in the Copper Zinc ratio will cause devia- from 0.5 to 4.0 per cent and act as grain refiners. Tin, up to tion in chemical properties as illustrated by the informa- 1.0 per cent and nickel up to 3.0 per cent are added mainly tion for alloy C86500 (Kramer A Manganese Bronze) in to increase corrosion resistance. the chart below. Minimum requirements are: Tensile strengths on the order of 125,000 psi and yield Tensile Strength 65,000 psi strengths of approximately 90,000 psi may be obtained on Yield Strength 25,000 psi castings without further thermal treatments. To obtain Elongation 20%

Fig. 5 Fig. 6 Fig. 9 Fig. 10

T.S. Y.S. % El. BHN (3000Kg) Fig. 5 56.01% Cu. 83,000 33,000 18.0 157 Fig. 6 57.28% Cu. 79,000 32,000 22.5 146 Fig. 7 58.47% Cu. 73,000 28,000 32.0 131 Fig. 8 59.73% Cu. 68,000 26,000 40.0 116 Fig. 9 61.30% Cu. 63,000 23,000 51.0 105 Fig. 10 63.46% Cu. 58,500 20,000 57.0 90 (All photomicrographs X100)

Fig. 7 Fig. 8

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4-9 These mechanical property results make it clear why it As a note of caution, the use of the single beta phase is necessary to control the copper-zinc ratio. At low copper high strength manganese bronzes should be avoided in content, elongation is too low, and at high copper content, certain corrosive media such as sea water, ammonia, acids tensile and yield strengths are too low. and liquid metals such as tin, lead, mercury, babbit and The following series of manganese bronze alloys il- solder. The beta manganese bronzes are subject to crack- lustrates the variation in microstructure and mechanical ing when the alloy is stressed while in contact with these properties caused by variations in the major alloying ele- corrosive media. The dual phase or alpha-beta manganese ments. This series illustrates the many types of manganese bronzes are less susceptible to this phenomenon. bronzes made by H. Kramer & Co. The relatively good corrosion resistance and high the base analysis for the series: strength of the manganese bronze alloys has made the group one of the most widely used alloys for marine appli- Cu 56.00 to 63.3 Fe 1.50 cations—propellers, rudder posts, and other marine hard- Al 1.05 ware. Other uses include ball bearing races, rolling mill Mn .45 bearings, gears, impellers, valve stems and many structural Zn Balance castings.

Fig. 11 Fig. 12

Kramer “XX” Manganese Bronze (X100) Kramer “F55” Manganese Bronze (X100) Cu 61.23 Al 5.40 Cu 67.10 Al 5.20 Fe 2.66 Zn Remainder Fe 2.80 Zn Remainder Mn 3.80 Mn 3.45 T.S. 120,000 T.S. 98,000 Y.S. 72,000 Y.S. 49,000 %EL. 18.8 %EL. 20.0 BHN (3000Kg) 230 BHN (3000Kg) 188

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4-10 Foundry Practice Although manganese bronzes are not as susceptible to gas pickup while melting as the other copper-base alloys, it is still recommended that they be melted under a slightly oxidizing atmosphere. Considerable care should be taken to avoid contamination by other copper alloys as the mechanical properties will be greatly impaired. Melt fast, preferably bringing the metal to the temperature where zinc just begins to flare. No deoxidation is required for manganese bronzes. In order to maintain a correct balance between the copper and zinc, usually 0.5 to 1.5 per cent of high purity zinc is Fig. 13 added. The amount added is a function of each individual foundry’s melting practice. Kramer “SX” Manganese Bronze (X100) The pouring temperature is usually a function of Cu 64.10 Al 4.05 type and size of casting being poured. This type of metal Fe 2.80 Zn Remainder Mn 3.15 should be poured just below that temperature where zinc T.S. 93,000 fumes are coming off the surface of the liquid metal. Low Y.S. 48,000 %EL. 20.0 BHN (3000Kg) 180

Fig. 14 Fig. 15

Kramer “X” Manganese Bronze (X100) Kramer “AX” Manganese Bronze (X100) Cu 58.20 Al 2.30 Cu 58.20 Al 1.70 Fe 1.50 Zn Remainder Fe 1.60 Zn Remainder Mn 1.70 Mn 1.50 T.S. 94,000 T.S. 84,000 Y.S. 44,000 Y.S. 42,000 %EL. 22.0 %EL. 20.0 BHN (3000Kg) 175 BHN (3000Kg) 155

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4-11 strength manganese bronze flares at about 1850°F while The location and size of risers cannot be universally the high strength alloys flare closer to 1950°F. stated, but they are very important. It is necessary to have Due to the aluminum oxide skin on these alloys, pour- additional risers, of increased size, over that required by the ing should be done with as little turbulence as possible, tin bronzes and red brasses in order to overcome the piping that is, pour evenly and as free from splashes, surges and type shrinkage of the manganese bronzes. stops as possible. The gating system should be designed to Considerable latitude is permitted in the types of give an even flow of metal with no sharp changes in direc- molding sands used for the manganese bronzes. The film tion or restrictions to cause squirting. On many large cast- of aluminum oxide gives a fair finish even when coarse ings reverse horn gates are used to bring the metal into the sands are used. The sands for these alloys should be kept mold cavity slowly and quietly from underneath the cast- dry to prevent the formation of surface drossing. Cores ing. These instructions are very important and will largely should be thoroughly baked and vented to prevent gas po- eliminate dross and oxide from being trapped in the cast- rosity in the castings. ing or on its surface.

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4-12 ALUMINUM BRONZES General Metallurgy On those aluminum bronzes with over 9.5 per cent Aluminum bronzes consist of a group of alloys of cop- aluminum and with only small additions of iron, nickel or per and aluminum with iron, nickel or manganese added manganese, care must be taken to remove the casting from for the enhancement of specific properties. These various the mold before black heat is reached in order to avoid em- combinations offer alloys of high strength, hardness, wear brittlement. Slowly cooled castings undergo what is termed resistance, fatigue strength and excellent corrosion resis- “self-annealing” and may produce a coarse structure with tance. Aluminum bronzes are also well suited for service at greatly reduced properties. Rapid cooling from red heat elevated temperatures—higher than for any other group of or the addition of iron, nickel or manganese will tend to cast copper-base alloys. minimize the problem of self-annealing or embrittlement. Typically, these alloys contain from 8.0 to 12.0 per The effect of self-annealing is illustrated in the accom- cent aluminum and up to 5.0 per cent each of iron, nickel panying photomicrographs. Comparing Figures 16 and 17 or manganese. Increasing the aluminum content causes a that have been heavily etched, it is difficult to determine the progressive increase in the tensile strenth, yield strength reason for the difference in properties. However when lightly and hardness with an accompanying decrease in ductility. etched as shown in figures 18 and 19, the reason for the dif- Tensile strengths of over 100,000 psi may be reached in ference becomes apparent. Slow cooling through the critical the as-cast alloy. temperature allows the beta constituent to decompose and Aluminum bronzes, in addition to being cast in vari- form the alpha-gamma eutectoid which strengthens the al- ous types of sand molds, have found wide application as loy to a higher degree than does the beta constituent. Figure castings made by the centrifugal, pressure die, plaster and 20 shows the alpha-gamma eutectoid at X 1500. permanent mold processes. 89-1-10 (10.4% Al) X50 Alloys with over 9.5 per cent aluminum respond to Fig. 16 and 18 Fig. 17 and 19 heat treatment similar to that given steel. Heat treatment Casting removed from sand Casting allowed to cool consists of a quench from 1550° to 1750°F followed by a 15 min. after pouring in sand to room temp. draw at 800° to 1200°F. The temperature of the draw must be selected in respect to the chemical composition in order 76,000 T.S. 64,000 28,400 Y.S. 33,700 to give the correct or specified combination of strength, 17.0 %EL. 8.0 hardness and ductility. 150 BHN (3000Kg) 155

Fig. 16 Fig. 17 Fig. 18 Fig. 19

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4-13 Heat treatment changes the appearance of the as-cast with care being taken to avoid extreme turbulence during alloy microstructure to a much finer structure. (Fig. 21). transfer from the furnace to the ladle. The charge should The tensile strength, yield strength and hardness have been be carefully inspected to avoid contamination with other increased considerably over the as-cast properties. classes of copper alloys as the properties may be greatly In the Nickel Aluminum bronzes, the general pattern impaired. Add 0.5 per cent of H. KRAMER & CO. NO. of the alpha-beta structure is the same as in the 89-1-10 77 ALLOY (Aluminum Bronze Deoxidizer and Degassi- alloy except for the reduction in particle size of the alpha fier) by stirring into the melt approximately three to five (Fig. 22). The peppery effect, as shown in Fig. 22 at X 1500 minutes before pouring. (See page 4-22—for procedure). is a nickel-aluminum compound which contributes greatly After removal from the furnace and skimming care- to the change in properties. fully, the metal should be allowed to cool down to the low- The aluminum bronzes are used where strength, hard- est temperature that will satisfactorily allow filing of the ness, ductility, wear resistance, bearing properties and cor- mold. Proper pouring temperature depends entirely on the rosion resistance are required. Specific uses include wear size and thickness of the casting, although 2100°F may be plates and guides, dies, valve seats, gears, rolling mill bear- considered as an average pouring temperature. ings and slippers, ball bearing races, non-sparking tools, Due to the aluminum oxide skin on these alloys, pour- marine propellers and pumps. ing should be done with as little turbulenceas possible— that is, pour evenly and as free from splashes, surges and Foundry Practice stops as possible. The gating system should be designed to The aluminum bronze alloys should be melted under a give an even flow of metal with no sharp changes in direc- slightly oxidizing atmosphere. Lift-out crucible furnaces tion or restrictions to cause squirting. On many large cast- are preferred, although tilting type furnaces may be used, ings reverse horn gates are used to bring the metal into the

Fig. 20 Fig. 21

Same sample as in Fig. 15 89-1-10 (10.4% Al) X50 This photomicrograph shows the alpha gamma eutectoid 1650° F—Water Quenched at high magnification (X1500). The pearlitic type struc- 1200 F°—Water Quenched ture is typical for this alloy when slowly cooled. T.S. psi 91,000 Y.S. psi 37,500 %Elong. 11.0 BHN (3000Kg) 175

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4-14 mold cavity slowly and quietly from underneath the cast- Molding sand should be rather open and kept on the ing. These instructions are very important and will largely dry side to prevent the formation of surface dross due to eliminate dross and oxide from being trapped in the cast- the boiling of water vapor through the metal. On large ing or on its surface. castings it has been found advantageous to use ceramic The location and size of risers cannot be universally gating systems to prevent the pickup of mold gases and to stated, but they are very important. It is necessary to have avoid dross formations. Extra venting of the mold should additional risers of increased size over that required by the also be provided. Cores should be thoroughly baked and tin bronzes and red brasses in order to overcome the piping vented to prevent gas porosity in the castings. type shrinkage of the aluminum bronzes.

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES 1. Melt under slightly oxidizing atmosphere. 2. Deoxidize and degassify with 0.5% H. KRAMER & CO. NO. 77 ALLOY. (See page 4-22). 3. Skim carefully, avoiding excessive agitation of the metal surface. 4. Pour at as low a temperature as possible. 5. Pour with as little stopping and splashing as possible. 6. Design gating for least amount of turbulence. 7. Provide risers at locations and of adequate size to overcome piping. 8. Molds should be relatively dry and thoroughly vented.

Fig. 22 Fig. 23

Nickel Aluminum Bronze (10.4% Al) X100 Nickel Aluminum Bronze (10.4% Al) X1500 T.S. psi 106,000 Y.S. psi 45,500 % Elong. 11.5 BHN (3000Kg) 203

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4-15 NICKEL SILVER ALLOYS General Metallurgy Foundry Practice The term nickel silver usually is applied to alloys of copper The melting and pouring practice for nickel silver is similar and zinc containing considerable amounts of nickel. For to that of the other copper-base casting alloys, except that many years these alloys were known as “German Silver.” the higher melting and pouring temperatures required ne- Nickel silver alloys are known particularly for their cessitate the use of proper melting equipment. As for all the excellent corrosion resistance and whitish color and they copper alloys, nickel silver should be melted under a slightly have superior resistance to tarnishing. oxidizing atmosphere. The best results are obtained by rapid In general as more nickel is added to copper-zinc al- melting and not holding the metal in the molten condition loys, corrosion resistance is increased while color becomes longer than the time required to bring the metal to the prop- whiter. At the same time, as nickel content increases me- er pouring temperature. Slow melting or long exposure of chanical properties are improved. Tin, found in most the metal to the fuel gases causes an absorption of gas, which nickel silver alloys, helps to improve corrosion resistance may cause considerable gas porosity in the casting. and castability while aiding in increased hardness and Glass is often used as a cover when melting nickel sil- strength. Lead is added to these alloys for improved pres- ver alloys high in zinc, such as the 57-2-9-20-12 and 60-3- sure tightness and machinability. 5-16-16, in order to prevent the loss of alloying elements by Nickel silver alloys have mechanical properties ex- vaporization and/or oxidation. celled only by the high strength brasses and bronzes. Their The deoxidation of nickel silver is a very important tensile strengths range up to 65,000 psi, yield strengths to step in the production of good castings. It is recommend- 30,000 psi, and elongations to 30 per cent. ed that an addition of 1/2-1 per cent of H. KRAMER & These alloys are used in corrosion resisting applica- CO. NO. 66 ALLOY be made about three minutes before tions such as dairy and food machinery parts, soda foun- pouring. The NO. 66 ALLOY should be plunged to the tain and restaurant kitchen equipment, plumbing fixtures, bottom of the pot or stirred in quickly in order to prevent steam fittings, valves and valve seats for elevated tempera- its loss by burning on the surface of the molten metal. (See tures, pump parts, business machine parts, ornamental Pg. 4-22 for procedure). and decorative hardware for marine and building applica- The metal should be poured very hot, keeping the sprue tions, jewelry, and statuary. filled. About 2450°F is the average pouring temperature for

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES 1. When melting nickel silvers high in zinc, add broken glass to bottom of pot at the start of melt. Melt oxidizing and rapidly and do not hold longer than necessary. With the high nickel, low zinc alloys, use of glass is optional. 2. After melting, add a little more broken glass to harden the slag; push slag to one side. 3. Add 1/2 percent H. KRAMER & CO. NO. 66 ALLOY, three minutes before pouring. (See Pg. 4-22). 4. Push slag to one side and pour metal very hot, keeping sprue filled. 5. Provide heavy gates and risers to feed heavy sections of castings. 6. Molds should be relatively dry and thoroughly vented.

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4-16 the higher nickel content alloys (20 and 25 per cent nickel). silver, liberal sized gates and risers should be used. Precau- For the nickel silvers with lower nickel and higher zinc an tions should be taken in locating risers to assure the hottest average pouring temperature of 2250°F will usually suffice. metal will be in the risers after pouring the mold in order It cannot be stressed too strongly that much better results to obtain directional solidfication. are obtained when nickel silvers are poured at a sufficiently Molding sand should be fairly open and kept on the high temperature. The tendency will be to pour at too low dry side. When pouring castings with fairly heavy sections, a temperature and for this reason pyrometer control is defi- thorough venting of the mold is a necessity. Cores should nitely recommended and should be used. be thoroughly baked and permeable enough to prevent gas Because of the relatively high shrinkage of the nickel porosity in the castings.

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4-17 TOMBASIL® AND SILICON BRONZE General Metallurgy hardware, catenary hardware for electrified railroads, and Casting alloys of copper containing silicon (silicon bronzes bells. Chemical corrosion applications for these alloys are and brasses) are widely favored for corrosion-resisting ap- pump impellers and pump bodies, valves, valve stems, plications because of their excellent foundry properties. and marine propellers. Copper-silicon alloys can be used In the as-cast condition, microstructures of the cop- in general for elevated temperature applications up to per-silicon alloys consist of copper-silicon solid solution 500°F and for such structural applications as gears and matrix with a silicide compound depending upon the sili- rocker arms. con content and alloying elements present. The mechanical properties of these alloys depend directly upon the amount Foundry Practices of this silicide compound precipitated during solidfication. Copper-silicon alloys should be melted under a slightly In general the greater amount of silicide present the harder oxidizing atmosphere. In regard to silicon bronzes, the and less ductile the alloy becomes. presence of a reducing atmosphere brought about by Commercial copper-silicon foundry alloys generally insufficient air supply may result in a large amount of gas contain from 3 to 5 per cent silicon with tin, manganese, porosity in the castings because of the high susceptibil- iron or zinc added to enhance properties. Depending on ity of these alloys to gas pickup while melting. Silicon the proportions of alloying ingredients present, mechani- brasses, due to their higher zinc content, are only slightly cal properties range from 45,000 to 75,000 psi in tensile susceptible to gas porosity. As is true with all copper- strength; 15,000 to 40,000 psi, yield strength; and 15 per base alloys, metal should not be held in the furnace after cent to 75 per cent elongation. proper temperature is reached. These alloys can be melted Copper-silicon alloys are generally divided into two in any of the standard furnaces used for the copper-base classes, namely silicon bronze and silicon brass. Silicon alloys, but in all cases be sure that the furnace atmosphere bronzes are generally defined as those copper-base alloys is not reducing. containing over 0.5 per cent silicon and less than 5 per cent For the best and most consistent results, the silicon zinc except that the copper content shall not be over 98 bronzes should be heated to a temperature approximately per cent. Silicon brasses are defined as those copper-base 200°F to 250°F above the desired pouring temperature. alloys containing over 0.5 per cent silicon and over 5 per KRAMER NO. 77 ALLOY should then be added. (See cent zinc. Pg. 22-Section 4.) The metal is removed from the furnace Silicon brass, better known as H. Kramer & Co. and allowed to cool by standing in air to the desired pour- TOMBASIL, is not only cast into green sand molds, but ing temperature. Large heavy castings should be poured also used for permanent molding, die casting and plaster between 1800° and 1900°F and small castings between casting processes. TOMBASIL’s low melting temperature, 1950° and 2050°F. Test bars should be cast at approxi- 1680°F, makes it excellent for such processes as mentioned mately 1850°F. TOMBASIL may be poured approximate- above where pouring temperatures in the range of 1700°- ly 100° cooler, and need not be superheated. 1850°F are required. In the case of permanent molding Metal should be poured slowly with as little turbu- and die casting, this improves die life and makes this alloy lence as possible. In general, the metal should enter the the best of the copper-base alloysin this respect. mold cavity near the bottom and with the least amount Copper-silicon alloys have excellent atmospheric cor- of splashing or squirting. Gates are preferably placed at rosion resistance and as such are used for such casting heavier sections, where it is possible to use risers which applications as memorial markers, electrical switch-gear will contain the hottest metal when pouring has been

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4-18 completed. The risers should be a mean of what would are obtained with a fairly open syntheyic sand with a be used in making tin bronzes and manganese bronzes; moisture content of not more than 4 per cent Any good that is not as small as in tin bronzes and not as large as for core sand mixture is satisfactory, providing it has plenty of manganese bronzes, but about half way between. permeability and is sufficiently soft to take care of heavy For the copper-silicon alloy castings, the best results shrinkage areas of the mold and casting.

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES 1. Melt oxidizing and do not hold longer than necessary. 2. For Silicon Bronzes add 1/2 per cent of KRAMER NO. 77 ALLOY about 3 minutes before pouring. For TOMBASIL there may be occasions where the addition of KRAMER NO. 77 ALLOY will prove beneficial. Here it should be added in the same manner as mentioned above for silicon bronzes. (See Pg. 4-22). 3. Pour at as low a temperature as possible. 4. Pour with as little turbulence as possible. 5. Gates and risers should be larger than those used for tin bronzes, but smaller than those used for manganese bronzes. 6. Use a fairly open and dry sand.

Fig. 24

Typical micro structure of Tombasil® (X100)

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4-19 DEVELOPMENT OF DOUBLE HORIZONTAL FULL-WEB TEST BAR

FIG. 2a Double Horizontal Full-Web Type Test Bars

The Research Laboratory of H. Kramer & Co. -in The double horizontal full-web test bar design proved vestigated many types of test bar designs that were in use to give maximum soundness and properties for all the in the late 1930’s, hoping that one of the designs could various cast copper-base alloys. The design did not require be used for determining the properties of all the various elaborate gating systems and was relatively easy to mold classes of sand cast copper-base alloys. The development of and pour. the double horizontal full web test bar came after testing In the 1940’s, the Brass and Bronze Ingot Institute many various designs of vertical and horizontal web and sponsored work at Battelle Memorial Institute on the ef- cast-to-shape bars and the keel block. The cast-to-shape fect of gases in 85-5-5-5 red brass alloy. One phase of the bars proved to produce unsound bars when used for the research program was to determine which design of test aluminum bronzes and manganese bronzes. The vertical bar would give the best indication of melt quality or gas Web-Webbert and the Crown test bar designs were un- content. Eleven various test bar casting designs were in- wieldly to mold and the gating was such that dross was vestigated and the H. Kramer & Co’s. double horizontal almost impossible to eliminate from the test section when full-web test bar design proved to give the best and most testing aluminum bronzes and manganese bronzes. The consistent indication of melt quality. (1) keel block design took an excessive amount of metal for the The double horizontal full-web test bar was also used test bar (and excessive machining costs) and also proved by Battelle Memorial Institute for determining the me- to produce unsound test bars in the tin bronzes and red chanical and physical properties of eight cast copper-base brasses. alloys: (2, 3, 4, 5).

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4-20 Kramer 5/8” Web-Webbert horizontal test bar casting.

ASTM B30 Alloy 922 88-6-2-4 Leaded Tin Bronze Fig. 9—Federal Test Method Standard No. 151—Metals; 836 85-5-5-5 Red Brass Test Methods 1. “Test Bars for 85-5-5-5 Alloy, Their Design and Some 937 80-10-10 High Lead Tin Bronze Factors Affecting Their Design” by Dr. G. H. Clam- 848 76-2½-6½-15 Semi-Red Brass er—A. F. A. Annual Foundation Lecture, 1946 865 65,000 TS Manganese Bronze 2. “Mechanical and Physical Properties of Three Low 863 110,000 TS Manganese Bronze Shrinkage, Copper-Base Casting Alloys” by Kura & Lang. ASTM Proceedings Vol. 58, 1958 976 20% Nickel Silver 3. “The Creep Properties of Three Low Shrink-age, Cop- 875 Silicon Brass (Tombasil) per-Base Casting Alloys” by Simmons & Kura, ASTM Various government agencies and the American So- Proceedings, Vol. 58, 1958 ciety for Testing Materials have indicated that the double 4. “Mechanical and Physical Properties of Five Copper- horizontal full web test bar design may be used as one of Base Casting Alloys” by Johnson & Kura, ASTM Pro- the acceptable methods for test bars for sand cast copper- ceedings, Vol. 60, 1960 base alloys. For example, the double horizontal full web 5. “The Creep and Rupture Properties of Five Copper- test bar is shown as: Base Casting Alloys” by Moon & Simmons, ASTM Fig. 3—ASTM B208—Recommended Practices for Tension Proceedings, Vol. 61, 1961 Test Specimens for Copper-Base Alloys for Sand Castings

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4-21 ELECTRICAL CONDUCTIVITY OF THE CAST COPPER BASE ALLOYS* Copper or alloyed copper castings are used in the electrical dard copper-base foundry alloys, and due to the highly industry for their current-carrying characteristics. Howev- oxidizable nature of their alloying elements (silicon, chro- er, sound copper castings, with a minimum of 85 per cent mium and beryllium), extra care is required in melting and I. A. C. S. electrical conductivity, are difficult to make. pouring. The ordinary deoxidizers, such as silicon, aluminum, zinc In many instances, where design permits the use of and phosphorus, cannot be used because residual amounts lower electrical conductivities, the standard copper-base lower the electrical conductivities drastically. foundry alloys may be used. Tables I through VIII list the Cast copper is soft and low in strength. Im- electrical conductivities of the various classes of copper- proved mechanical properties with good conductivity base casting alloys. (40 to 80 per cent I. A. C. S.) may be obtained with heat- *Data from A.F.S. paper “Electrical Conductivity of Sand Cast treated alloys containing silicon, cobalt, chromium, nickel Copper-Base Alloys” by F. L. Riddell and D. G. Schmidt—A.F.S. and beryllium in various combinations. However, these Transactions, 1959. alloys are expensiveand less readily available than the stan-

TABLE 1 — ELECTRICAL CONDUCTIVITY OF SAND-CAST TIN BRONZES AND LEADED TIN BRONZES Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Sn Pb Zn Fe Sb Ni P 89-11-0-0 89.0 10.6 trace trace 0.03 trace trace 0.24 9.6 88-10-2-0 87.5 9.3 2.2 0.3 0.02 0.09 0.4 0.02 11.0 88-10-0-2 86.8 10.1 0.2 2.5 0.06 0.03 0.3 0.02 10.9 88-8-0-4 87.6 8.2 0.15 3.8 0.08 0.03 0.1 0.01 12.4 88-6-2-4 88.3 6.0 1.8 3.1 0.08 0.10 0.6 0.01 13.8 88-5-2-5 87.0 5.3 2.2 4.5 0.15 0.03 0.5 0.01 14.1 87-11-1-0-1 (Ni) 87.6 10.2 1.0 0.3 0.01 0.03 0.9 0.01 11.1 87-11-1-0-1 (Ni) 87.0 10.5 1.0 0.3 0.01 0.03 0.9 0.19 10.1 87-11-1-0-1 (Ni) 86.0 10.6 1.1 0.7 0.10 0.03 1.0 0.31 9.2 87-11-0-1-1 (Ni) 85.9 11.5 0.2 1.0 0.03 0.03 1.3 0.01 10.1 87-10-1-2 86.7 9.7 0.9 2.1 0.10 0.10 0.4 0.02 10.8 87-10-2-1 86.4 9.7 1.6 1.6 0.03 0.10 0.5 0.01 11.0 87-8-1-4 87.5 8.0 0.7 3.3 0.15 0.10 0.2 0.02 12.3 88-5-0-2-5 (Ni) 87.1 5.4 0.01 2.4 0.03 0.02 5.1 0.01 11.5 88-5-0-2-5 (Ni) (Cooled in sand to room temp.) 11.9 88-5-0-2-5 (Ni) (H.T. — 1400 F - 4 hr - oil quench + 600 F - 5 hr - air cool) 14.8 87-5-1-2-5 (Ni) 86.5 5.1 1.1 2.1 0.10 0.02 5.0 0.02 12.0 87-5-1-2-5 (Ni) (H.T. — 1400 F - 5 hr - air cool + 600 F - 7 days - air cool) 15.7 85-9-1-0-5 (Ni) 83.6 9.2 1.2 0.4 0.1 0.02 5.2 0.01 10.3 84-16-0-0 83.9 15.4 0.05 0.3 trace 0.02 0.02 0.01 8.5

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4-22 TABLE 2 — ELECTRICAL CONDUCTIVITY OF SAND-CAST HIGH LEAD TIN BRONZES Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Sn Pb Zn Fe Sb Ni P 87-4-8-1 86.4 4.1 8.0 0.9 0.02 0.15 0.30 0.01 16.4 85-5-9-1 83.4 4.5 9.8 1.4 0.03 0.20 0.50 0.02 14.9 84-8-8-0 83.3 7.4 8.1 0.5 0.02 0.20 0.25 0.01 11.8 84-4-8-4 84.4 4.0 8.3 2.7 0.10 0.10 0.40 0.01 16.9 83-7-7-3 82.8 6.8 7.5 2.1 0.10 0.15 0.60 0.01 12.4 81-8-9-0-2 (Ni) 82.2 7.0 9.0 0.2 0.01 0.20 1.25 0.01 12.1 80-10-10 79.7 8.8 10.1 0.7 0.01 0.20 0.35 0.01 11.0 78-7-15 77.4 6.8 14.5 0.7 0.03 0.30 0.25 0.02 11.6 75-3-20-0-2 (Ni) 75.0 3.4 18.4 0.3 0.05 0.15 2.20 0.01 14.2 75-13-10-0-2 (Ni) 74.8 13.1 9.4 0.5 0.02 0.15 2.00 0.01 8.6 73-5-22 73.1 4.2 21.9 0.1 0.01 0.05 0.50 0.01 14.1 66-2-32 66.1 1.9 31.0 0.1 0.01 0.05 0.50 0.01 17.8

TABLE 3 — ELECTRICAL CONDUCTIVITY OF SAND-CAST LEADED RED BRASS AND LEADED SEMI-RED BRASS Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Sn Pb Zn Fe Sb Ni P 93-1-2-4 93.1 0.9 2.5 3.0 0.05 0.05 0.30 0.01 32.4 85-5-5-5 84.6 4.5 5.3 4.6 0.10 0.15 0.65 0.02 15.0 83-4-6-7 82.4 3.8 6.4 6.5 0.20 0.20 0.50 0.02 15.2 83-3-3-11 82.9 3.0 2.9 10.1 0.20 0.15 0.70 0.01 16.7 81-3-7-9 81.2 2.6 7.2 8.0 0.25 0.15 0.50 0.02 16.6 80-5-5-5-5 (Ni) 79.9 4.8 5.4 4.6 0.30 0.15 4.80 0.02 11.1 78-3-7-11-1 (Ni) 79.7 2.6 6.2 10.0 0.25 0.15 1.10 0.01 16.0 76-3-6-15 74.6 3.2 7.3 14.3 0.15 0.10 0.30 0.01 16.6 76-2½-6½-15 76.7 2.4 6.5 13.6 0.30 0.10 0.35 0.02 17.7 76-2-6-16 75.3 2.1 6.9 15.0 0.15 0.10 0.35 0.03 19.0 76-1-6-17 75.9 1.1 7.6 14.8 0.15 0.10 0.30 0.02 21.3

TABLE 4 — ELECTRICAL CONDUCTIVITY OF SAND-CAST YELLOW BRASS Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Sn Pb Fe Sb Ni Others 72-1-5-22 72.8 1.6 4.7 0.4 0.2 0.6 18.6 68-1-3-28 68.1 1.0 2.3 0.3 0.1 0.2 19.6 64-0-0-35-1 64.5 0.05 0.1 0.1 trace trace 1.1 Si 15.1 63-1-1-35 61.9 0.6 1.0 0.2 0.05 0.3 22.0 63-1-1-35 61.8 0.7 1.1 0.2 0.05 0.1 0.25 Al 21.8 60-1-0-38-1 59.9 1.0 0.04 0.01 0.05 0.3 1.15 Al 23.7 60-0-3-37 61.5 0.1 2.8 0.10 trace trace 0.06 Al 25.7 60-0-1-38-1 59.5 trace 1.0 0.30 0.01 0.05 1.1 Al 26.5 60-0-0-40 60.9 0.05 0.1 0.4 trace 0.05 0.8 Al 24.9 60-0-2-38 58.7 0.05 2.2 0.1 trace 0.02 26.4 58-1-1-40 58.6 1.0 0.8 0.5 0.01 0.10 0.5 Al 23.3 52-0-0-48 52.4 0.1 0.05 0.01 trace trace 0.4 Al 35.8

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4-23 TABLE 5 — ELECTRICAL CONDUCTIVITY OF SAND-CAST ALUMINUM BRONZES Alloy Nominal Condition Composition, per cent Average % Composition of Bars I.A.C.S. Cu Fe Al Mn Ni Copper-Aluminum 95-5 As-cast 94.8 0.01 5.1 trace 0.03 17.0 90-10 As-cast 88.8 0.10 11.0 0.01 trace 13.6 88-12 As-cast 87.9 0.10 11.8 0.01 0.05 20.3 Copper-Iron-Aluminum 90-1-9 As-cast 89.1 1.5 9.2 0.10 0.10 12.9 89-1-10 As-cast 88.2 1.4 10.1 0.01 0.03 15.1 89-1-10 Heat treated* 88.2 1.4 10.1 0.01 0.03 12.7 88-3-9 As-cast 87.4 3.4 8.9 0.06 0.20 12.2 86-4-10 As-cast 85.9 3.4 10.4 0.06 0.05 14.6 86-4-10 Heat treated* 85.9 3.4 10.4 0.06 0.05 12.4 84-4-12 As-cast 84.4 3.5 11.8 0.05 0.05 16.8 81-5-14 As-cast 80.8 4.8 14.0 0.20 0.05 10.8 Copper-Iron-Aluminum-Nickel 88-1-10-1 As-cast 88.1 0.8 9.9 0.01 1.1 13.4 87-1-10-2 As-cast 87.1 0.9 9.8 0.06 2.1 12.2 84-4-10-2 As-cast 83.4 3.9 10.4 0.1 2.1 11.0 84-4-10-2 Heat treated* 83.4 3.9 10.4 0.1 2.1 10.2 81-3-11-5 As-cast 81.5 2.9 10.5 0.1 4.9 9.4 81-4-11-4 As-cast 81.6 4.0 10.4 0.1 3.8 10.3 80-5-10-5 As-cast 79.5 4.8 10.2 0.1 5.2 8.9 80-5-10-5 Heat treated* 79.5 4.8 10.2 0.1 5.2 8.4 76-5-14-5 As-cast 76.7 4.4 14.0 0.2 4.6 12.6 Copper-Iron-Aluminum-Manganese 85-3-11-1 As-cast 85.3 2.6 10.7 1.1 0.05 10.5 85-3-11-1 Heat treated* 85.3 2.6 10.7 1.1 0.05 9.4 Copper-Iron-Aluminum-Nickel-Manganese 80-5-9-5-1 As-cast 78.9 4.5 9.6 1.4 5.4 6.9 79-5-9-5-2 As-cast 78.9 4.8 9.1 2.1 4.8 6.5 78-5-9-5-3 As-cast 77.3 4.8 9.6 3.2 4.9 5.8 *Heat Treatment — 1650 F (905 C), 2 hr, water quench, plus 1100 F (595 C), 1 hr, water quench.

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4-24 TABLE 6 — ELECTRICAL CONDUCTIVITY OF SAND-CAST HIGH-STRENGTH YELLOW BRASS (MANGANESE BRONZE) Alloy Composition, per cent Average % I.A.C.S. Cu Fe Al Mn Others 60.000 psi T.S. 58.8 0.9 0.7 0.4 0.6 Sn 19.3 0.8 Pb 65.000 psi T.S. 58.4 1.0 1.0 0.25 21.9 Nickel Manganese Bronze 53.9 1.6 1.3 3.2 3.2 Ni 80.000 psi T.S. 58.5 1.6 1.7 1.0 16.7 90.000 psi T.S. 59.1 1.6 2.2 1.7 14.5 90.000 psi T.S. 64.0 2.2 3.9 4.0 7.4 90.000 psi T.S. 58.4 2.0 3.1 0.1 24.0 90.000 psi T.S. 66.8 2.5 5.4 3.9 7.4 110.000 psi T.S. 62.5 2.7 6.0 3.8 7.9

TABLE 7 — ELECTRICAL CONDUCTIVITY OF CAST SILICON BRONZES AND SILICON BRASSES Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Fe Mn Si Zn Others 96-1-3 95.8 0.15 1.1 3.0 0.1 6.5 95-1-4 94.7 0.2 1.1 3.8 — 5.9 95-1-4 95.0 0.1 — 3.7 0.3 0.8 Sn 6.6 92-4-4 92.0 0.1 — 4.4 3.5 6.1 91-4-3-1 ½ 90.4 1.2 — 3.2 4.6 0.4 Al 7.4 91-2-7 90.5 0.1 — 2.2 0.2 7.1 Al 8.8 86-2-7-5 85.9 0.1 0.02 2.0 4.9 7.0 Al 7.3 90-4-2-4 90.2 0.2 0.01 1.4 3.6 4.5 Al 10.7 81-4-15 81.9 0.2 0.01 4.0 13.9 6.5

TABLE 8 — ELECTRICAL CONDUCTIVITY OF SAND-CAST NICKEL SILVERS AND COPPER-NICKEL ALLOYS Alloy Nominal Composition, per cent Average % Composition I.A.C.S. Cu Sn Pb Zn Fe Ni Others 9% Nickel Silver 50.6 1.4 0.1 35.3 1.1 10.5 1.0 Al 9.4 12% Nickel-Copper 84.8 0.01 0.01 0.01 0.9 12.0 1.2 Al 10.1 0.7 Mn 12% Nickel Silver 64.5 2.6 6.3 14.3 0.6 11.4 6.5 12% Nickel Silver 54.7 1.9 9.9 19.7 1.2 12.4 5.7 15% Nickel Silver 63.1 2.2 7.3 10.5 0.5 16.0 5.4 18% Nickel-Copper-Zinc 64.8 trace trace 8.5 1.0 17.7 8.0 Al 9.3 20% Nickel Silver 65.0 3.7 3.8 6.0 1.0 20.2 5.0 20% Nickel-Copper-Zinc 57.6 0.3 0.5 21.0 1.2 19.5 0.25 Al 4.7 23% Nickel-Copper-Tin 63.6 10.2 0.05 1.8 0.8 23.4 5.6 25% Nickel Silver 59.5 1.3 2.0 10.9 1.6 24.4 4.2 25% Nickel Silver 65.7 4.7 0.9 2.8 0.8 25.0 4.6 28% Nickel-Copper 66.8 trace trace trace 4.3 28.1 0.6 Mn 5.2 30% Nickel-Copper 68.8 trace trace trace 0.5 29.3 0.7 Mn 4.6 0.7 Si

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