Furnace Technology Product Portfolio, Technology & References Economical and Environ- Ment-Friendly Furnace Technology from the System Supplier

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Furnace Technology Product Portfolio, Technology & References Economical and environment-friendly furnace technology from the system supplier

SMS group is able to deliver nearly all thermal same time more difficult. With SMS as a technolo- processing equipment which is required to pro- gy partner the complete know-how for heating and duce modern steel and aluminum products. SMS cooling throughout the complete process chain can designs, erects and commissions furnaces for the be supplied from one source and high material qua- different production steps of carbon steel, electrical lity can be ensured. silicon-steel, stainless steel, and aluminum. This In this brochure you‘ll find comprehensive informa- includes furnaces for heat treatment of strip and tion about our products, technologies, services and hot-formed materials like heavy plates, tubes and references of furnace technology. bars as well as reheating furnaces. Common to all furnaces is high cost-effectiveness that results from constant improvement, quality consciousness, and a focus on saving resources. Drawing on the combined strength of SMS group, the furnaces can be supplied from one single source.

Key factor furnace technology Furnace technology is considered to be the core process for the production of modern materials, since it determines the material properties and the quality of the final product. Controlled heating or cooling is the only way for the manufactures to produce high-quality, marketable finals goods. Often, cooling is more important than heating but at the CONTENTS General Introduction 2 Highlights 4 Processes 6 Product Portfolio 8 System Supplier 10 SMS-FLAME® 12 Effective Lining Solutions 14 SMS-PrometheusTM 16 DFC-Model (Dynamic Furnace Control) 18 Service 20 Workshop 22

Heat Treatment of Strip 24 Carbon Steel Annealing & Galvanizing 26 I-Furnace 30 Batch Annealing 36 Continuous Tinplate Annealing 38 Electrical Silicon Steel Strip Processing 40 Stainless Steel Strip Annealing 46 Color Coating 52 Aluminum Heat Treatment 56

Furnaces for Slabs, Bars and Tubes 58 Roller Hearth Furnaces 60 CSP®-Roller Hearth Tunnel Furnaces 62 Chamber Furnaces 64 Walking Beam Furnaces 66 Walking Hearth Furnaces 70 Pusher Furnaces 72 Fields of Application Long Products 73 Flat Products 74 Pipes and Tubes 76 Forged Products 80

Heat Treatment of Hot-Formed Material 82 Heavy Plates 84 Roller and Platen Quench 86 MultiFlex-Quench® 88 Tubes and Pipes 92 SMS-Quench® 96 Bright Tubes 100 Bars 102

3 Numerous References

Since 2000, SMS group has attracted orders for more than 150 furnaces for carbon steel silicon steel, stainless steel and aluminum to produce high quality strips, plates, bars or tubes including all important types of furnaces and cooling technologies.

Steel and NF-metal producers using furnaces from SMS (examples)

Acroni Outokumpu Amag Rolling Panzhihua Iron & Steel AM/NS Calvert POSCO Angang Steel Company PRO-TEC Coating Company Aperam Salzgitter Flachstahl ArcelorMittal Severstal ASAŞ Alüminyum Shagang Group Baosteel Shandong Nanshan Baoxin Shougang Jingtang Bengang Shougang Corporation Big River Steel SSAB China Steel Corporation Steel Dynamics Incorporated Deutsche Edelstahlwerke Stefana Handan Iron & Steel Taigang Henan Zhongfu TKAS Terni Hyundai Steel ThyssenKrupp Steel Ilva Tianjin Tiantie Jisco Tianjin Zhongwang Ma‘aden-Alcoa Joint Venture Timken Maanshan Iron & Steel TMK Artrom MMK Toscelik NAS North American Stainl. US Steel NLMK Voestalpine Nucor Steel Wuhan Iron & Steel

4 Market leadership The majority of market leading steel and NF-metal producers rely on SMS group's technology.

High product quality Significant to all furnaces is the high quality of the final product. Thus, the furnaces are especially designed to ensure flawless surfaces and homogenous material characteristics.

Flexible production Flexible production conditions allow a quick reaction to changing market demands with the greatest economic efficiency. SMS group has developed several furnace solutions for highest flexibility.

System supply SMS group is capable to deliver almost all furnaces completely from one single source. This means, you get everything you need out of one hand and without any interface problems.

Production know-how SMS group offers process support for all materials and qualities. This covers both metallurgical and design actvities as well as support during commissioning, operation, quality control and certification.

Ecoplants All furnaces are designed to keep resource consumptions as low as possible. All technologies and processes are continuously evaluated in order to improve their eco-friendliness.

Project Management A professional project management aligned with latest knowledge and international standards ensures in combination with modern design methods, a consistent and reliable fulfillment.

Manufacturing The set-up includes several modern and well equipped manufacturing locations worldwide to ensure a high level of quality control and proximity to the customers.

Modernizations SMS possesses rich experience and offers comprehensive services for refittings and upgrades. Starting from the exchange of a single parts up to major modernizations of complete furnaces with several measures.

Industry 4.0 The furnaces use production and process models which are deeply integrated in the automation system and linked with other systems.

5 Furnace technology based on thermal processes

Furnace technology is driven by thermal processes cesses of the steel and NE-metal production route. to change material characteristics and enhance the Depending on the different materials requirements material quality – and therewith the value of the and material developments, SMS offers special solu- material – step by step. SMS group has extensive tions to fulfill highest demands. know-how and understanding of all thermal pro- Energy Source

Combustion gas Electrical energy

Furnace Atmosphere

Open atmosphere with exhaust gas Closed atmosphere with shielding gas

6 Heating processes

Convection Radiation Induction

cooling agents

Gas Water Mist

7 Product Portfolio-Furnace Technology: Overview

Heat treatment of strip

Carbon Steel Annealing and Galvanizing

See pages 26-35

Stainless Steel Strip Annealing

See pages 46-51

Furnaces for slabs, bars & tubes

Roller hearth furnace

See pages 60-61

Walking Beam Furnace

See pages 66-69

Heat treatment for Hot-formed material

Heavvy Plates

See pages 84-93

8 Electrical silicon Batch Annealing Tinplate Annealing steel strip processing

See pages 36-37 See pages 38-39 See pages 40-45

Aluminum Heat Color coating treatment

See pages 52-55 See pages 56-57

CSP®-Roller Hearth Chamber Furnace Tunnel Furnace

See pages 62-63 See pages 64-65

Walking Hearth Pusher Furnace Furnace

See pages 70-71 See pages 72-73

Besides those main furnace types and heat treatment processes, SMS group Tubes Bars offers various other concepts or variations of processes depending on the individual customer requirements. See pages 94-101 See pages 102-103 Modernizations – from small improvements to vast revamps – are also a part from SMS group's product portfolio

9 System Supplier

SMS group is the only company worldwide capable of delivering nearly all furnaces and heat treatment systems for steel and NF-metal production route as a full system supplier. That’s because all products and services are available within the SMS group.

auxiliaries Heating System Cooling System

Handling equipment Radiant tube furnaces Gas cooling

Roller tables Direct fired furnaces Water spray cooling

Charging/discharging machines Floatation furnaces Roller/platen quenches

Guiding systems Catenary furnaces Mist cooling

Water treatment plants Reheating furnaces Laminar cooling

Hydraulic systems Inductive heating Air cooling

10 Advantages due to complete system supply:

Perfect match of all components Clear responsibility

Electrical and Cooling System Special Services Automation system

Gas cooling Level 1 to level 3 Production know-how

Water spray cooling Process and production models Startup assistance

Roller/platen quenches Quality monitoring systems Continuous production assistance and process optimization Mist cooling Measuring systems Qualification assistance Laminar cooling Plug & Work integrations tests Certification support Air cooling Operation and visualization

11 SMS-FLAME® High-efficiency burners for varied application. A new concept in burner development

SMS applies a new concept in burner design and development and is capable for offering a full line of advanced SMS-Flame® burners. These are available in a wide range of power sizes and in different models suitable for varied application:

SMS-ZERO Flame®, the new frontier of natural gas-

flameless combustion. Extra-Low NOx emissions at any rating and combustion air temperature

® SMS-ECO Flame , a reliable unit combining low NOx capability and high efficiency, available for any gas or liquid fuel – also available in radiant configuration for roof installation

SMS-DUAL Flame®, capable of dual fuel utilization, gaseous fuel and oil

EFFICIENT BY DESIGN A strong synergic approach between research and experience in furnace realization allows designing burners suitable for any kind of furnace.

“Flexibility” is the keyword of the research approach, based on field tests, performed in combustion laboratory, and Computational Fluid Dynamics (CFD).

Before manufacturing and testing the prototypes in the laboratory, SMS identities the most promising design using detailed CFD-based modelling. Prediction of flame reaction zone profile, temperature gradients and pollutants generation are only some of the aspects that are modelled and optimized with CFD software before starting the test campaign on a real burner.

12 VERSATILE BURNERS FOR OPTIMISED COMBUSTION Different products require different temperature profiles. With SMS- FLAME® burners, plant engineers can flexibly adapt the combustion parameters to diverse process conditions.

The shape and temperature control of the flame outline helps to contain the overall emissions: when firing in flameless mode, the SMS-ZERO Flame® burners not only dramatically decrease 3 the NOx formation, (<70 mg/Nm at

3% O2 DFG), but also improve the temperature homogeneity inside the furnace chamber.

® Measured NOx emission with SMS-ZERO Flame burners, in flame and in flameless mode.

Burners are studied and developed by means of most advanced techniques: the first phase foresees CFD modelling, often followed by 3D printer proto-typing.

Later the burners need to go through extensive laboratory tests, in order to assess their genuine capability to steadily meet the emission parameters foreseen by the software simulations.

13 EFFECTIVE LINING SOLUTIONS Tailored to the particular properties of each plant

SMS group pays great attention to design and component features that allow for the lowest possible FORM FOLLOWS FUNCTION energy consumption. The furnace specialists continu- When designing a new reheating furnace or a ously test new materials, components and concepts. heat treatment plant, the experienced SMS en- The results are self explaining: energy requirements gineers use both their know-how and advanced below 260 kcal of heat input per kilogram of steel computational modelling tools. With state-of-the- reheated from 20 to 1,200 °C minimise energy costs art CAD and FEM software they create smooth, in long product rolling mills. Another example is a fast and precise mechanical designs for any heat- total fuel energy consumption of less than 280 kcal ing task. per kilogram required in a quench and temper cycle, 3D modelling is also an invaluable benefit for the where the workpieces are heated from ambient tem- field engineers and erection crews on site, as all perature to 900 °C for hardening then, having been details can be clearly understood at a glance. One quenched, reheated again to over 500 °C to com- example is pipe routing detail engineering with plete the tempering process. 3D CAD programs: it simplifies and speeds up ADVANCED LINING the erection works so costs are reduced and the Refractories play a key role in containing energy plants can be commissioned earlier. dissipation and in improving the efficiency of old The digital modelling of a walking beam frame furnaces. In extensive field tests SMS examined is an efficient tool in removing interferences and different lining materials and their impact on energy quota errors from the design. Loads and forces efficiency. Based on the test results, the furnace spe- are calculated rapidly with no risk of errors. cialists select the best material for each furnace.

14 OPTIMIzED RESISTANCE Improvements in material quality, durability and safety beneficial for heat treatment furnaces. The modern allow for the utilisation of modern light-weight fibre fibres are characterised by an enhanced resistance insulations for applications traditionally reserved for to higher temperature conditions and by a certified castable and plastic refractories. Low thermal inertia absence of hazardous compounds, compared to and optimised resistance to repeated thermal cycles similar linings available in the past. make this class of lining materials especially

15 SMS-PROMETHEUSTM Combustion optimization for tailored steel quality and reduced fuel consumption

With SMS-PrometheusTM, plant operators are able tors, although even highly experienced staff benefit to boost their furnace’s overall performance. The ad- substantially from the mathematical model guidance vanced combustion optimisation system improves during transitory events. those parameters that can make the difference in EFFICIENCY INDEX special steel quality production. SMS-PrometheusTM SMS-PrometheusTM tracks the consumption and the allows for targeted improvements of the metallurgi- other efficiency related parameters and stores the cal properties, for example increased temperature trends over time in order to allow prompt monitoring. uniformity or minimised negative effects such as steel decarburisation or high scale formation. Heat flow charts and consumption trend bars help FUEL – ONLY AS MUCH AS YOU NEED to control furnace efficiency. SMS-PrometheusTM helps to reduce fuel consumption by adopting those heating strategies that minimise the temperature set points and yet guarantee the required final stock target temperature. The core of the program is a sophisticated mathematical model capable of simulating the heating curves inside the furnace for each stock loaded. The system shows the overall furnace efficiency by visualising heating balance diagrams. It also provides consumption and emission trends that can be correlated to actual production data.

SMS-PrometheusTM constantly monitors the heating history parameters of each single workpiece. The ADVANCED FEATURES – ROUGHING system works predictively, meaning it makes con- MILL PYROMETER FEEDBACK sistent projections to estimate the development of This function adapts the mathematical model accord- the heating path. On this basis, SMS-PrometheusTM ing to the roughing mill pyrometer measurements. continuously chooses and modifies the temperature The temperature of the piece measured by the pyro- set points. When coupled with SMS-Digiburn®, the meter is compared to the expected one and adapts system also optimises the digital firing pattern. the model accordingly.

ENERGY SAVINGS – EVEN DURING NONPRODUCTIVE TIME SMS-PrometheusTM is highly efficient in optimising the combustion parameters during events like sud- den stoppages, furnace heating-up time or changes to the product campaign. This tool ensures proper heating repeatability, even with inexperienced opera-

16 ADVANCED FEATURES – SKID MARKS EFFECT prediction FROM DETAILED INFORMATION This function allows to monitor the “skid marks TO COMPREHENSIVE OVERVIEW effect” by means of a specific algorithm which simu- The overview screen shows the furnace loading lates cold spot effect generated by water cooled pattern and provides the main data relevant to the skids, managing different parameters of the auto- temperature set points of the different heating mation and combustion system according to the zones. process requirements.

ADVANCED FEATURES – PACING MODEL The model forecasts the time in which each piece inside the furnace will be ready to be discharged to fulfill the minimum heating/soaking time requirement of each piece inside the furnace and get the maxi- By selecting a specific billet, the engineer obtains mum productivity. the real-time heating status of any single workpiece.

17 DyNaMiC Furnace Control

Energy savings and higher CSP® Furnace in three dimensions. It calculates the production with a CSP® furnace set-point temperature for the furnace zones which The Dynamic Furnace Control (DFC) level 2 process depends on the entry temperature of the slab and automation system is an integral part of SMS group's the set-point exit temperature for the slab. During energy saving and high production strategy. Integrated commissioning, the model for the slab temperature in a CSP® Furnace it ensures heating of the slab to is adapted to fit the real slab temperature. the required target temperature with good uniformity The tracking module synchronizes the position of the and without energy wastage. It allows the application slabs in the furnace.The control parameters of the logi- of different strategies to heat-up and accerlerate the stics (acceleration point and ferry usage) are comput- slab, which offers several operational advantages. ed. This is of particular interest after mill idle when the Therefore, the DFC system calculates the 3D tem- furnace is relatively full and needs to return to statio- perature distribution for each slab and the buffer nary position. Moreover, the buffer time is determined time. Furthermore, the model provides an effective which enables the operator to judge if a roll change in emptying of the furnaces after roller change by defin- the mill is possible without scrap cutting. ing the sequence of the slabs for rolling. The system Furthermore, the DFC calculates the theoretical gas continuously communicates with CSP® Furnaces consumption of the furnace adapted during the com- Level 1, Level 3, CSP® Caster Level 2 and CSP® Mill missioning of the furnace. If this value differs con- Level 2. It generates several reports and diagrams to sistently from the actual gas consumption, it is time support monitoring and furnace control. for maintenance. The model can be further used to Temperature calculation and identify the part of the furnace that needs to be control checked (for instance rolls or the recuperator). The As mentioned above the DFC-system simulates the heat balance includes walls, rollers, waste gas and temperature of the slabs while going through the pre-heated air and is calculated for each zone.

Level 3 Slab ID, target temp. for slab Caster speed, slab dimensions and temp. Slab temp. info Furnace Caster Mill Buffer time Level 2 Slab request Level 2 (DFC) Level 2

Zone temp. setpoints Actual values for temp. Setpoints for logistics logistics and energy. Caster Furnace Mill Level 1 Level 1 Level 1

Communication with other CSP® components.

18 Main advantages of DYNamic Furnace Control (DFC)

Energy saving due to reduced set-point tempera- Effective emptying of the furnace after roller tures for the furnaces zones change by defining the sequence of the slabs for rolling Reduced wear on rollers and slabs by shifting the setpoint for the acceleration roll Automatic communication with other automation levels and moduls (Industry 4.0) Higher yield due to avoidance of slab cutting by early accerleration of the slabs Automatic generation of reports and diagrams

3D calculation and visualization of the slab temperature.

Each heat-up process for every slab is efficiently calculated and controlled.

19 SERVICE Taking care of everything

Whether you want spare parts, modernizations, that our employees provide the services you require – tailor-made maintenance procedures, or customized on schedule, within budget, and in the right quality. training programs, the Technical Service Division of That means you can rely on the quality of our ser- SMS group is ready at 50 locations around the world vices as well as our global presence to reduce down- to offer you service packages geared to your require- times, increase productivity, and ensure the lasting ments along the entire metallurgical process chain. value of your machinery and plants. It’s due to the know-how of the entire SMS group

Spare Parts & Logistics Upgrades & Modernization OEM spare parts Mechanical & hydraulic Spare parts management Electric & automation Warehousing Value added components

Maintenance & Repairs Consulting & Training Emergency support Fact finding Inspection, repairs, servicing Maintenance audits Maintenance tools Feasibility studies Long term maintenance services TECademy

THE RIGHT PARTS IN THE RIGHT PLACE AT THE RIGHT TIME The right spare parts have to be available at all times so that production doesn‘t come to a standstill. At the same time, capital tie-up and storage costs have to be kept low. That is why SMS group delivers spare and wear parts for all machines quickly and reliably.

A web-based, machine-specific parts catalogue makes the ordering process even easier. On request, SMS group also takes care of the whole spare part and stock management. The differing parts stocking concepts are always geared to the customers‘ individual needs. Water-cooled furnace rolls with fireproof insulation made of aluminum silicate wool allow higher temperatures and at the same time low energy losses in a CSP® Furnace.

20 CONTINUOUS HIGH PERFORMANCE CORPORATE SUCCESS due TO Whether one-off fact-finding, continuous monitoring TECHNICAL KNOW-HOW via remote service or regular plant inspections. The Whether individual or standardised trainings – our SMS group Service experts analyse and service the experts plan individually tailored training programmes plants. Not only this, the complete maintenance can and implement these together with the customer. be taken over by SMS on request. Plant owners thus The plant operators gain valuable know-how through ensure maximum plant availability and optimum pro- time-tested formats and special e-learning offerings duction results. for more operational reliability and more efficient processes. ALWAYS UP-TO-DATE Plant owners are engaged in dynamic markets. The HIGHER PROFITABILITY due TO THE demands on profitability, product quality and produc- RIGHT ADVICE tivity have risen steadily for plant owners in recent More efficient processes, optimised technology and years. New technologies and plants arrive on the more effective use of resources – those are the market in ever shorter innovation cycles. Tailored goals of our consulting concepts. SMS group carries and customised modernisation concepts from SMS out feasibility studies to establish a sound basis for group ensure that the plants run for decades and that management decisions, or develops strategies and with reduced operating costs, higher productivity and concepts for the optimisation of existing plants and improved product quality. processes.

FIELD SERVICE Even in emergencies, customers can rely on SMS Examples of service parts group Service. The Service technicians help with CSP® Rolls troubleshooting and the necessary repairs. With - Dry rolls short reaction times and high availability, they ensure - Water cooled rolls with fiber insulation that the plant is up and running again as quickly as Furnace rolls for strip processing lines possible. Isolation materials Energy saving concepts Consulting for optimal integration of the furnace operation into the overall process

21 WORKSHOP R&D testing, equipment pre-assembly and inspection under one roof

SMS group runs a fully equipped workshop for the details, especially to the electrical pre-wiring of the assembly and testing of key components in Tarcento, sensors and components to the terminal boxes. Italy. Prototypes, special equipment and machines Before being disassembled and shipped, each com- which require extremely accurate tolerances are ponent and module is marked for fast and error-free assembled here. The workshop operates in close reassembly at the business partner’s site. conjunction with the R&D and technical departments. FUNCTIONALITY TESTS ENSURE A constant and precise exchange of information and MAXIMUM RELIABILITY ideas is the basis for the continuous further develop- The workshop is equipped with testing motors, ment of all components. switchboards and Programmable Logic Controllers PREASSEMBLY FOR FASTER (PLCs) so the SMS group engineers can simulate COMMISSIONING production conditions for factory dynamic tests. All Most machines are completely preassembled – the hydraulic equipment is checked during cold test including hydraulics, lubrication and cooling water runs with hydraulic units and benches. units. The engineers pay great attention to the

22 PREASSEMBLY SAVES TIME AND MONEY SMS preassembles and tests even large components so its business partners save commissioning time and labour costs at the erection site.

OPEN FACTORY POLICY SMS business partners are invited to visit the Tarcento workshop. They can assure themselves of the strict quality assurance standards and take a close look at the machines during all assembly phases according to inspection schedules.

23 24 HEAT TREATMENT OF STRIP

Furnace technology is considered to be the core process for the production of high-quality strip materials, since it determines the material properties and quality. Often, cooling is more important than heating but at the same time more difficult. SMS offers proven heating and cooling systems for all strip processing lines.

Carbon Steel Annealing & Galvanizing page 24

Batch Annealing page 36

Continuous Tinplate Annealing page 38

Electrical Silicon Steel Strip Processing page 38

Stainless Steel Strip Annealing page 46

Color Coating page 52

Aluminum Heat Treatment page 56

25 Carbon Steel Annealing & Galvanizing

Excellent quality, high effi- It has been proven that SMS has the competence ciency and enormous capacity to design, engineer, erect and put into operation During heat treatment in annealing and galvanizing furnaces for all kinds of modern annealing and galva- lines, microstructure is precisely adjusted to meet nizing lines. requirements strength and formability. Annealing and galvanizing furnaces by SMS are characterized in particular by the excellent quality of the end product, high efficiency and economy, as well as – if demanded – enormous capacities. In recent years various improvements and new technical solutions have been developed, particularly regarding furnace concepts, furnace efficiency and cooling technology. Special efforts were also made to adapt the galvanizing furnace to the new challenges which came up with modern and sometimes high-alloyed steel grades.

High-quality end-products, which are often determined by the furnace technology, are crucial for the economical success of a cold strip processing line.

SMS group‘s strip processing lines feature large vertical furnaces which ensure a high strip speed in the furnace 26 also for big cross-sections in order to achieve high capacities. Production of automotive grades Steel continues to be the most important construc- Hence, furnaces for the production of high-quality tion material for the automotive industry, whereby steel strips for use in interior and exterior compo- particularly the share of high-strength steels in cut- nents (usually annealing or galvanizing furnaces) throat competition with other materials is constantly must be set up to produce high material strengths increasing. As manufacturers are required to build and flawless surfaces. A crucial part for flawless sur- light and fuel-efficient vehicles, many new steel faces is a surface-friendly annealing process, which grades with optimized combinations of properties for example keeps the surfaces clean and controls have been developed. Multi-phase steels, which are or prevents oxidations processes. In order to high-strength and very ductile, are increasingly being achieve an outstanding material strength, advances used for car components. These high-strength yet annealing and cooling strategies are implemented. easily deformable steels must meet the highest quality requirements for use in automobiles, whereby not only the material properties, but also the surface quality must be of a high standard.

In automotive construction, a growing number of steel grades with higher strength and good forming properties are used.

27 Carbon Steel Annealing & Galvanizing: Concepts

ConTInuous Annealing

The Full-radiant tube furnace is the biggest part of a cess and gives the material the desired mechanical continuous annealing line. The annealing and cooling properties. In the overaging section carbides are re- process reduces strain hardening from the rolling pro- moved from the material to minimize the risk of aging.

Hot-dip Galvanizing

In a vertical hot-dip galvanizing line, which is often material has to be annealed to restore drawability used to produce unexposed and exposed automotive and adjust the mechanical properties. Secondly, the parts, the furnace has two main tasks. Firstly, the material has to be prepared for galvanizing.

Horizontal Hot-dip Galvanizing

Horizontal galvanizing lines are intended mainly also in part for automotive applications. The furnace for the production of material for the construction, again has the task to adjust mechanical properties household appliances and furniture industries, but and to prepare the material for galvanizing.

28 Universal Annealing with Gas and Water Cooling

This universal furnace concept offers two cooling the current market conditions. In this way, it is pos- options: gas and water cooling. On this line, different sible to produce the most valuable products every products can be produced very flexibly according to time.

Universal Annealing and Galvanizing

The universal annealing and galvanizing line features fully equipped continuous annealing line or as a hot- a furnace with both: a hot-dip galvanizing section and dip galvanizing line and it is possible to switch be- an overaging section. Thus, this line can be used as a tween annealed or galvanized material very flexibly.

All-Purpose

The furnace in an all-purpose cold strip processing gether four completely different process routes, this line offers two cooling options and the possibility to is the most flexible concept for cold strip production. produce annealed or galvanized material. With alto-

29 Carbon Steel Annealing & Galvanizing: Technology

I-Furnace predict material characteristics (e.g. tensile strength) The Intelligent Furnace by SMS is a smart furnace depending on annealing and cooling temperatures as process and production optimization model. The well as treatment curves. Furthermore, the model combination of various tools leads to an optimized can be used offline to lay-out the furnace exactly heat treatment and production process. It smartly according to the process requirements and limits. combines a mathematical/physical model to control the furnace and to optimize production with EMGs- IMPOC system for online strength measurement and a newly developed annealing microstructure model to predict material properties after the heat treatment. This intelligent combination of efficient tools is a great step forward towards an autonomous working furnace.

Special sophisticated grades can be produced more easily and homogenous material characteristics over the whole coil length can be achieved. A capacity increase up to 15 percent is possible due to a better utilization of the furnace capacity as well as an efficient production planning and transition behavior. Also energy savings can be realized due to a better temperature control close to its lower limit (in average -10 K).

The annealing microstructure model in combination with the data collected by the other tools can be used offline to develop new materials. It’s possible to Automatic furnace and line speed control by furnace mathematical/physical model.

30 Only Measurement of Material Properties The IMPOC measuring system of EMG Automation and forcing the steelmakers to check the quality GmbH – integrated in cold strip processing lines within their lines. The IMPOC system is perfect for continually checks the material’s tensile strength automatic, non-destructive, online testing of ferro- and yield strength during production. That allows the magnetic steel strips with thicknesses from 0.15 to 6 operator to immediately adjust process parameters millimeters. This system is based on two identically whenever necessary. Non-destructive magnetic constructed sensors, which are arranged on the measurement shows that homogeneous material upper and underside of the strip. Each sensor con- properties over the whole coil length are achieved sists of a magnetizing coil and a magnetic even at high tensile strengths. field probe for recording the remanent magnetic induction. Since today many automotive manufacturers use this system for checking materials, the material requirements of the automotive industry are increasing

Pre-Oxidation Chamber Some modern high-strength steel grades contain high silicon and/or manganese contents. These alloying elements migrate to the surface during annealing and create wettability problems which can lead to bare spots. With a controlled infusion of humid air into the pre-oxidation chamber the dew point gets altered. This creates a closed iron-oxide layer on the surface and suppresses the migration of silicon and manganese to the surface. At the end of the furnace a reduction of the iron-oxide layer takes place and the resulting surface has the required wettability.

As a result, with this technology it is possible to gal- vanize also high-alloyed high-strength steel grades which leads to an extension of the product range of every line. Another economic benefit is the substitu- tion of expensive alloying elements with silicon.

31 Carbon Steel Annealing & Galvanizing: Technology

Rapid Cooling with Gas is the addition of pure hydrogen directly into the The ultra-fast cooling System (UFC) allows to realize cooling chamber. The hydrogen content there is up uniform cooling rates of up to 150 Kelvin per second to 50 percent, thus permitting the high cooling per- and millimeter of strip thickness in radianttube fur- formance. A complicated separation of the cooling naces of galvanizing lines or annealing lines. The zone from its neighboring sections is not needed results are excellent strip geometry and optimal sur- owing to the natural diffusion of the gas to the other faces. Thus, it is possible to obtain high-strength areas. Neither does the system normally requires multi-phase steel grades such as DP and TRIP having more hydrogen than the conventional furnace mode tensile strengths of up to 1,000 megapascals. Further- with the inert gas containing a hydrogen share of five more, some steel grades can be produced using less percent. In customary radiant tube furnaces, the inert alloying elements due to the higher possible cooling gas is mixed automatically and fed into the furnace at rates. This implies greater product diversity at lower various places. operating costs. The cooling gas is applied to the strip via nozzles Higher cooling rates are obtained by adding pure with transverse slots to ensure uniform cooling hydrogen to the cooling chamber without increasing over the full strip width, thickness, and length. The the total hydrogen consumption of the line. The gas distance between strip and nozzles can be infinitely pressure may be reduced, and the consumption of varied between 40 and 120 millimeters. Despite the electrical power decreases by an amount up to 40 high flow rate, the cooling chamber, thanks to its percent. The cooling system takes advantage of the special design, safeguards great strip stability with a properties of hydrogen (low density and high thermal minimum of vibrations. conductivity) to enhance the cooling capacity. A special feature of the patented ultra-fast cooling system

Quenching and ParTITIoning SMS offers also furnace concepts for quenching and partitioning of steel grades to produce for example martensitic steel grades with enhanced levels of retained austenite. The furnace comprises high- speed cooling systems and subsequent high- frequency induction heating modules. Within this two-step thermal treatment the material is cooled down with high cooling rates and afterwards heated up via induction.

The ultra-fast cooling system (right) serves for the production of high-strength steel grades with cooling rates of up to 150 Kelvin per second per millimeter.

32 Intensive Cooling with Water The water-spray cooling system is specifically designed to produce ultra high-strength steel strips for internal parts of a vehicle. The system is able to attain tensile strengths of partly more than 1,700 MPa. These high strength dual phase and complex phase as well as martensitic grades are mainly used Water-spray cooling for producing steel grades with tensile to produce crashproof core components in the pas- strengths of up to 1,700 megapascal with cooling rates of senger compartment such as the A-pillar and B-pillar, more than 1,000 Kelvin per second per millimeter. door beams and roof bows. That's the way steel products improve the safety of modern automobiles and, at the same time, reduce their weight. action under high pressure creates turbulences that The water-spray system is able to achieve cooling ensure fast dissipation of the heat energy. In the rates that are distinctly above those attainable by gas nozzle chambers cooling by more than 600 Kelvin is cooling sections. Due to the high specific heat capac- achieved for example within less than half a second. ity of water, a large amount of heat energy can be During this short period the steel strip microstructure dissipated through spraying within a very short time. is completely transformed as a result of dimensional The cooling rates thus achieved are above 1,000 Kel- changes. In co-action with a strip shape control, the vin per second and millimeter. special nozzle configuration ensures a uniform coo- In the water-spray section, the strip immerses in ling result over the entire strip width, preventing the demineralized water and both sides are sprayed with formation of distortions or flatness defects. water by special nozzles. This continuous spraying

Flexible Annealing Curves A comparison of typical annealing curves for different high-strength steels shows that cold strip processing furnaces must offer considerable flexibility with regard to heat treatment. Equipped with various cooling systems the processing furnaces of SMS group are capable to produce the latest high-strength steel grades for the automotive industry. That allows for lighter and fuel-saving vehicles.

Precise Following of the Heating Curves The precise and speed control with the mathematical/ Comparison of different cooling curves for the production of physical control model enables the furnace to follow modern high-strength steel grades. the specified annealing curve exactly. Thus, every steel grade gets just the heat treatment which is demanded for the required material characteristics. This also applies to the transitions area around the weld seam when the material properties or geometry changes.

33 Carbon Steel Annealing & Galvanizing: References

MMK Magnitogorsk Iron and Steel Works, Russia

Hot-dip galvanizing line and complete with Plug-and-Work integration tests. Both universal annealing and plants went on stream in summer 2012. As early as galvanizing line the end of November, MMK issued the final approval The two cold strip lines in the MMK plant in for the lines after an effective start-up phase. Magnitogorsk, Russia, together produce more than one million tons of high-quality steel strips, especially for automotive outer and interior parts. This is where SMS erected a pure hot-dip galvanizing line and a universal annealing and hot-dip galvanizing line. It is a plant array that covers a very wide range of top- quality materials – from mild to high strength grades – and produces two different product groups (annealed and galvanized) as required.

Everything for the lines was supplied from one source: mechanical equipment and hydraulics, air knives, posttreatment and of course the powerful full-radiant tube furnaces. Furthermore, SMS was responsible for the entire electrical and automation systems Bypass around the zinc pot for annealing mode.

Two powerful furnaces serve for the production of more than one million tons of high-quality steel strip, particularly for the automotive industry.

34 Since in the PRO-TEC line two options for fast cooling of the material are available, different cooling strategies can be applied which leads to a drastically increased product spectrum.

PRO-TEC Coating Company, USA

Continuous annealing line Among other sophisticated technologies, the line fea- with rapid gas cooling and tures a high-capacity furnace with an integrated ultra water spray cooling system fast cooling system and a water-spray cooling system PRO-TEC Coating Company (PRO-TEC), USA, suc- for particularly high cooling rates, which allow the cessfully commissioned a new continuous anneal- manufacturing of fully martensitic grades and ultra- ing line for the production of cold-rolled ultra-high high-strength multi-phase steels. strength steel coils. The line was completely supplied by SMS group and is located in Leipsic, Ohio. In February 2013, the first sellable prime coil was produced. Besides the design and production of the mechanical equipment as well as the furnace and process technology, the complete electrics and automation package was part of the supply scope of SMS group.

Each year, 500,000 short tons of steel strips for automotive structural components for cars, trucks and sport utility vehicles can be produced, with a view to both improve the safety of vehicles and reduce their weight. The annealing process and special high cooling rates, along with tempering, reduce the strain hardening in the material caused by the rolling process and enable the high-grade metallurgical properties to be attained.

The full radiant tube furnace ensures an economical production of high-strength and ultra-high-strength materials.

35 Batch Annealing

Discontinuous Annealing of SMS uses modern batch annealing technology which Cold strip is based on the use of 100 percent hydrogen atmo- After cold rolling the steel strip is hard and brittle. It sphere to increase the heat transfer and prevent the has to pass a recrystallization annealing process to strip surfaces from oxidation. The heating bell serves achieve the necessary ductility for the later cold for the heat-up of the annealing furnace up to recry- forming process. stallization temperatures which differ for each material. For the cooling process special cooling bells are Batch annealing furnaces (also called bell type used with a combined air/water cooling technology. furnaces) serve to anneal and cool the cold rolled and already cleaned material in the batch mode. Batch annealing furnaces offer the highest flexibili- Depending on the required capacity numerous anneal- ty when it comes to different material grades with ing bases with several heating and cooling hoods are different strip dimensions. This is because every installed in a production plant. The heat treatment anneal-ing base works independently. The size of the process for each hood takes between one and three whole plant – i.e. the number of the annealing bases days depending on the batch size and material grade. is always adapted to the required production rate. Of Each hood can process several coils at once. The course, it is easily possible to add some bases to an coils are stacked one on the other using intermediate existing plant when necessary. convector plates for strip edge protection and to increase the heat transfer. The coil stack is covered with an inner cover to ensure an oxygen-free protective atmosphere. A heating or cooling bell is put over the inner cover depending on the current process phase.

In the annealing base an impeller and a diffuser ensure a The inner covers are being put over the coil stack to have an high circulation rate of the protective gas. atmosphere containing 100 percent hydrogen around the coils.

36 Reference: Big River Steel, USA

Latest Batch Annealing several coils simultaneously with a maximum batch Furnaces height of 6.4 meters, a maximum batch weight of Besides an annealing and hot-dip galvanizing line, 140 tons and a maximum coil outer diameter of SMS group will establish batch annealing furnaces 2,000 millimeters. The treatment takes between for cold strip treatment at Big River Steel’s new mill 42 and 55 hours. In total, 24 bases with 13 heating complex in Osceola, in the state of Arkansas, USA. hoods and 11 cooling hoods will be installed to These furnaces serve to anneal and cool cold strip achieve a throughput capacity of 413,000 tons of coils in the batch mode. They are able to process steel per annum.

For a high heating and cooling result the gas has to flow through the convector plates.

The gas flow inside the inner cover is optimized with CFD Batch annealing furnaces serve to anneal and cool cold strip simulation (computational fluid dynamics). coils in the batch mode and are able to process several coil simultaneously. For cooling and heating different bells are used, while the coils remain in the inner cover under 100% hydrogen atmosphere.

37 ConTInuous Tinplate Annealing

Fast processing of thin strips The full radiant tube furnace is the heart of the Tinplate annealing line. During the annealing process, the strip is treated in the individual furnace sections according to defined annealing curves. This serves to remove strain hardening. First, the strip is heated up to about 750 °C. After the soaking section, in which this temperature is held for a certain time, the material is cooled down fast to some 100 °C, which sets the desired microstructure of the material. In the following overaging zone carbides are eliminated from the steel which minimizes the risk of aging. Finally, cooling units lower the temperature of the strip to about 40 °C. A protective gas atmosphere with hydrogen content of 5 percent or less prevents oxidation on the strip surface in the heating zones. A constant slight overpressure in the furnace prevents The material is annealed in a very environment friendly air ingress into the furnace. The product range com- way in a full radiant tube furnace with atmosphere con- prises all grades and also contains the qualities T2.5, trol and special designed rolls. T5 and DR 10, which cannot be produced by batch annealing.

Highlights Low resource consumption

Precise following of the heating curve

Mathematical model with speed control

Experience in heating very thin strips up to 750 °C

High process speed (up to 750 m/min)

Special roll profile design The precise furnace and speed control with a mathematical Rapid cooling with temperature transversal control model enables the furnace to follow the specified annealing (edge damper) curve for the different grades exactly.

38 Furnace in the continuous annealing line for tinplate production which was erected completely by SMS for the Shagang Group.

Reference: Shagang Group, China

Tinplate production plants duction plus surface treatment. In a powerful Shagang Group, China, has successfully commis- radiant tube furnace, the strip is processed according sioned its new annealing line and the electrolytic to an exactly defined annealing curve with a process- tinning line both supplied by SMS group in 2014. speed of up to 720 meters per minute. The width of Being a systems provider, SMS supplied all compo- the strips treated here may vary between 700 and nents including electrical and automation equipment. 1,250 millimeters, and it is possible to process strip gauges of 0.18 to 0.55 millimeters. The annealing line with a yearly capacity of 418,000 tons provides the strip with the required material and surface properties by annealing and subsequent re-

In a tinplate annealing line the full radiant tube furnace is the biggest and most quality-decisive part. Annealing and cooling reduces strain hardening from the rolling process and adjusts the desired mechanical properties. Carbides are removed in the overaging section to avoid subsequent aging.

39 Electrical Silicon Steel Strip Processing

Processing furnaces to ensure the required electromagnetic properties

SMS group supplies processing furnaces for the pro- as power transformations. Manufacturing electrical duction of electrical silicon steel strips from non-grain strip requires a highly complex production route oriented grades to high-permeable grain oriented including sophisticated strip treatment strategies. grades. The demand for electrical steel strip is grow- The main material properties are set through the heat ing steadily due to its electromagnetic properties treatment of cold strip. Thus, furnace technology and that lead to a significant increase in energy efficiency thermal processing are the crucial parts in producing when this strip is used in electric applications such high-quality materials.

Non-Grain Oriented and Grain Oriented Electrical Steel

There are two groups of electrical steel steel: non- grain oriented (NGO), and grain oriented (GO). In NGO electrical strip, the iron grains are distributed in a non-ordered way so that the material has largely the same, so called isotropic magnetic properties in all directions. That is why NGO electrical strip is mainly used in rotating machines such as electric motors and generators with alternating field orientation.

Grain oriented electrical strip is used in energy- efficient transformers. (©Dieter Schütz/PIXELIO).

In GO electrical strip, the microstructure (grains) are arranged in the direction of cold rolling, resulting after special heat treatments in what is called cube-on- edge texture. Because of the uniform orientation of the grains, the electrical strip has a preferred direction in which the magnetization can occur relatively easily. Due to the high permeability and lower losses in this preferred direction, GO electrical strip is typically used in static machines such as transformers.

Non-grain oriented electrical strip is used in wind turbines for electricity generation. (©Thorsten Wengert/PIXELIO).

40 Process Know-How

Support for all grades and production routes In cooperation with MET/Con, SMS group offers process support for all grades and production routes. This covers both metallurgical and design activities as well as support during commissioning and operation. The experts involved look back on long production experience and offer full parameter sets from steelmaking to final processing. This ensures safe production also of difficult and high-quality grades. Furthermore, operational costs can be minimized, for example through greatly reduced use of alloying All furnaces and processing lines feature special elements. equipment tailor-made to the particular requirements of silicon steel strip.

Smooth strip running is enshured by heating of the coils as well as the strip edges to avoid strip breaks.

41 Non-Grain Oriented Electrical Silicon Steel Strip

Furnaces for annealing and coating lines The most important processing line for fully-finished non-grain oriented (NGO) material is the annealing and coating line. One highlight is the recrystallization furnace with a hydrogen content of up to 100 percent. For contactless drying of the coating, a floatation furnace with a high specific heat transfer is installed.

Furnace in an annealing and coating line.

Thermal simulation of the heating process in an NGO- NGO electrical strip is mainly used in rotating machines furnace. such as electric motors and generators with alternating field orientation.

42 The horizontal furnace in the new annealing and coating line for ArcelorMittal St-Chély d`Apcher.

Reference: ArcelorMittal, France

New furnace for an annealing coated with an insulating layer. The strip is heated anD coating line up to 1,100 °C by means of inductors and electrical In its new annealing and coating line, ArcelorMittal heating elements in the horizontal annealing furnace. St-Chély d`Apcher, France, processed the first coil in The atmosphere in the furnace comprises a nitrogen/ March 2013. Thanks to good preparation by all hydrogen mix whereby the furnace can be opera- participants, the commissioning was done quickly ted with hydrogen content up to 100 percent. This within a few weeks. Already one month after the reducing atmosphere helps to achieve a particularly furnace had dried out, the production reached the oxide-free and clean strip surface, which is important nominal rate. for a high-quality material grade. Furthermore, the careful and slow cooling of the material is important With the new line, ArcelorMittal St-Chély d`Apcher is for the microstructure. For this reason, the strip is drastically increasing its production capacity of high- first cooled down at a very accurate cooling rate in grade non-grain oriented electrical steel strips (NGO). the slow-cooling section and then in the rapid cool- Among other products, the furnace processes the ing section. Due to the high annealing temperatures newly developed iCAReTM material by ArcelorMittal and the very high hydrogen content in the furnace, which helps automakers to offer environmentally ArcelorMittal achieved very good material properties friendly mobility solutions for a greener world. right from the start. Especially the core losses are In the annealing and coating line, the internal micro- already at the level of those attained by the best pro- structure of the electrical steel strip is adjusted ducers in the world. during the annealing process. The material is then

43 Grain Oriented Electrical Silicon Steel Strip

Setting the main material than 600 °C. In the soaking section, the atmosphere properties is humidified to adjust the carbon content. After The focus in the production of grain oriented silicon- annealing, strip is coated with a magnesia solution grades is on the heat treatment of the cold strip, as and dried. the main material properties are set in this stage. In batch annealing, the second recrystallization takes The first heat treatment in the annealing and pickling place and the steel is purified from the inhibitor line is to recrystallize the steel and to obtain the elements. The strip is annealed at a temperature of appropriate quality and size or inhibitor precipitates. maximum 1,200 °C by a heating hood. The furnace is composed of a direct flame furnace, In the flattening and coating line, the goal is to dry followed by a radiant tube furnace. The strip is the tension active solution coated just before the annealed at a maximum temperature of 1,170 °C. furnace and to improve the strip flatness. The first The strip is then cooled to 900 °C and soaked for a section, in which the tension active coating is dried, minute. A cooling air and/or water is used to cool the is of the catenary type and heated by direct flame strip to the exit temperature. In case of production burners. Radiant tubes heat the second section of of HiB grades, the cooling gradient should be higher the furnace. The annealing temperature is about than 35 K/s between 900 °C and 400 °C. 870 °C. A pair of flattening rolls is installed when this During decarburized annealing, the carbon content temperature is reached. A slow-cooling and a fast- in the steel making process is high in order to avoid cooling follow this section when the strip tempera- abnormal grain growth in the slab. This carbon has to ture is below 600 °C. The final cooling is achieved be removed at this stage to avoid aging. The heating with air-cooling. The control of the annealing curve is achieved due to radiant tubes. The annealing tem- and the furnace atmosphere as well as the strip perature is between 830 and 900 °C. The cooling is tension, which could cause negative impact on final divided in two stages: slow-cooling at the beginning magnetic properties, and the improvement of the flat- and fast-cooling when the strip temperature is less ness are the most important issues in this stage.

Furnace in an annealing and coating line.

44 Catenary furnace for contact-free drying of the insulation layer.

Reference: Wisco, China

Two furnaces for flattening and coating lines SMS supplied two furnaces for Wisco’s new two flattening and coating lines in China. These two lines are used to enhance the production of HGO grades around 180,000 tons. Both furnaces were successfully commissioned in 2012. Without a stop for the first five months after start-up, both furnaces have been operating and produced, among other grades, HGO materials in the low-temperature mode. The furnaces feature new technologies for thermal flattening as well as for cooling, which improve surface quality and process control.

Strip entering the drying and sintering furnace, which is divided into a radiant tube and a direct-fired section.

45 Stainless Steel Strip Annealing

Powerful furnaces for stainless steel strips SMS group offers perfect concepts for all thermal process stages of stainless steel strip which are characterized by their efficiency, sophisticated production models and powerful environmental technology. All this leads to low production costs, high energy efficiency and outstanding environmental compatibility. The scope comprises of all significant furnaces for stainless steel strip treatment. Besides furnaces for annealing of hot strip and cold strip SMS also delivers furnaces for bright annealing lines.

Hot strip Annealing and Pickling Lines

Horizontal furnace in a stainless steel hot strip annealing line.

Cold strip Annealing and Pickling Lines

Horizontal furnace which is capable to anneal stainless steel cold strip.

46 In hot strip as well as in cold strip annealing and pickling lines the furnace plays a major part when It comes to material quality, operational costs and environment friendliness.

47 Stainless Steel Strip Annealing – Technology

The furnaces are designed to optimize energy utilization and environmental compatibility. The strip is preheated in a radiation zone which operates with the exhaust gases from the downstream heating furnaces. To increase the thermal efficiency, a special heat recovery system is used. The process parameters are set and controlled by a mathematical model over the entire annealing cycle, which is also combined with the pickling model to match up and optimize both processes. More than 25 SMS furnaces for stainless steel strip processing have been ordered since the year 2000 worldwide.

The support rolls in the furnace are designed as easy-to- maintain "carrousel rolls" and can be changed within 15 minutes without disturbing operation.

Heat recovery system Thanks to an intelligent heat recovery system, the extracted at the furnace front end and, with the aid furnace achieves excellent thermal efficiency. The of a recuperator, are used for preheating the combu- strip is heated up in two zones by means of direct stion air. Thus, the exhaust gases of the furnace are firing. The hot waste gases are then led through the used to preheat the combustion air as well as the preheating zone in the opposite direction to strip- strip in the first parts of the furnace. travel and heat up the strip. Finally, the gases are

48 Water cooling for hot strip In hot strip processing, a special water cooling technology ensures a better strip quality due to faster cooling and a better control of the last heating zone. The efficient system results in a shorter cooling section and massive electrical savings. Furthermore, the impact on the environment is minimized because there are no dust emissions and no vibrations or noise.

Mist cooling for cold strip The mist cooling technology reduces the length of the energy consuming air-cooling section and elimi- nates the final cooling performed by water, since this can generate cooling buckles. In total, 17 annealing and pickling lines have been equipped with mist cooling sections. Due to reduced blower motor power and exhaust motor power, electrical energy is saved. Moreover, water consumption can be reduced drastically. This adds up to annual operational savings which significantly reduce production costs.

49 Stainless Steel Strip annealing – References

North American Stainless (NAS), USA High-performance furnace for The technological highlight of the bright annealing line the production of bright- is the entirely electrically powered vertical furnace. annealed stainless steel strip Thanks to the furnace’s high operating efficiency, the North American Stainless (NAS), USA, a subsidiary energy consumption, at approx. 220 kilowatt hours per of the Spanish Acerinox Group, has contracted SMS ton, is 60 percent lower than in a conventional design group for the supply of a complete bright annealing with a muffle furnace. Furthermore, the shorter hea- line. NAS is erecting a modern, high-performance ting section enables the bay height to be reduced by production facility for bright-annealed stainless 50 percent. The high efficiency is achieved by means steel strip in Ghent, in the U.S. state of Kentucky. of direct heating via electrical heating elements and The in-stalled plants will be characterized by high dynamic annealing at up to 1,250 °C. The annealing efficiency, flexibility and product quality. The output process takes place in a pressurized inert atmosphere capacity of the plant will be 95,000 tons per year. (up to 90 percent hydrogen). This ensures a low dew Commissioning will take place in early 2017. point and produces an immaculately reflective surface. A special strip stabilization system allows contactless The new line will manufacture both austenitic and fer- positioning of the strip, preventing surface damage. ritic grades (AISI 300 and 400 series). The end ma- The total furnace construc tion is made gas tight. terial will be between 600 and 1,350 millimeters wide, Special sealing elements at the entry and exit mini- and between 0.15 and 1.5 millimeters thick. In addition mize losses. In order to keep the hydrogen require- to the supply of the mechanical, process, furnace, elec- ment low, a recycling unit will be integrated to conditi- trical and automation equipment, also the supervision on the used hydrogen and return it to the process. For of installation, commissioning support and training of strip cooling, the furnace will be fitted with two inert the operating personnel belong to the contract scope. gas recirculation units. The bright annealing line will be the highest-performance line of its kind in the USA. Here the material will be annealed with a speed of 50 meters per minute in an oxygen-free, inert atmosphere with high hydrogen content, creating a high-grade, reflective strip surface. The technological highlight of the new NAS line is the entirely electrically powered vertical furnace with a pressurized inert atmosphere (up to 90 percent hydrogen).

The bright annealing line operated by an electrical furnace convinces through highly efficient production of stainless steel strips with extremely high-grade surfaces.

50 The furnace serves for the production of 140 tons of hot strip per hour or 90 tons of cold strip per hour.

Outokumpu Stainless, USA Annealing and pickling lines thick material (up to 10 millimeters). The yearly for cold and hot strip capacity is 750,000 tons including AISI 200, 300 and The annealing and pickling line for hot and cold stain- 400 grades. The line went on stream in 2011 with less steel strip is an integral part of a new cold rolling excellent results so far. The thermal treatment of the mill for stainless steel in Alabama, USA, owned by strip takes place in a modern horizontal furnace with Outokumpu Stainless Steel USA. The line is able to various innovative features. produce flexible hot and cold strip as well as very

With a length of almost 140 meters the furnace is capable The intelligent heat recovery system ensures a high-thermal to heat the strip up to 1,150 °C. efficiency.

51 Color CoaTIng

Efficient drying furnaces for steel and aluminum strips Color coating lines apply a high-quality coating to the strip so that it can be used directly for processing into end products. This saves costly process stages. SMS group delivers color coating lines for various applications of aluminum and steel strip. The lines differ depending on the final use of the material. The lines are delivered completely from a single source and feature several outstanding processes. The highlight of the lines is the compact coating process. Chemical strip pretreatment, subsequent color coating and drying oven are ideally synchronized. This way it is possible to attain a high product quality at low consumption of resources and energy. The high-performance floatation or catenary ovens to dry the solvents stand out for even heating and cooling performance as well as exceptionally high efficiency and eco-friendliness. All this requires ideal setting and control of the process parameters, ensured with a mathematical model. The air is heated by burners that work with reheated combustion air, yet require a very low energy input.

Contact-free strip travel Nozzles in the floatation oven ensure the strip travels contact-free through the oven and air cooler in a sinus shape. This is possible because, throughout the oven length, hot-air nozzles heat the strip evenly and keep it afloat on an air cushion. With interaction of the mechanical drive, a fault-free strip transport is generated. The ovens are designed with several modular heating and curing zones for best processing and strip quality. In a floatation oven the strip travels on air cushions without any mechanical contact.

52 Regenerative Thermal Oxidizer (RTO) The flue gases of the oven are burned in a regenerative thermal oxidizer system (RTO) with a thermal efficiency of 98 percent. Depending on the solvent A regenerative thermal oxidizer system burns the solvent- containing exhaust air and regains the energy produced. content in the exhaust air, the after burning system and even the oven itself can be operated without additional energy input (autothermal mode).In color coating lines, solvents are evaporated so as to cross- link the varnish molecules and to cure the varnish. The type of heating of the ovens is specified on the basis of the product portfolio and the product mix as well as an energy balance and economic calculation. Thus, concepts with autothermic operating practice of the ovens have already been realized over of a wide product range. The exhaust gases are extracted and combusted via a regenerative thermal oxidizing system (RTO) with a high thermic operating efficiency. Depending on the solvent content of the exhaust air, the post combustion system and, if an energy recovery system is employed, also the ovens themselves can be operated without additional energy supply. For products, where the energy demand is in balance with the generated energy of the solvents by the heat recovery system, the curing oven operates with autothermal mode.

In a color coating lines – here for aluminum can-end stock material – a floatation oven is used to evaporate the solvents without contacting the material to make the color layer curing on the strip.

53 Color CoaTIng: References

Severstal, Russia

Two color coating lines for carbon steel strip Severstal's new color coating line in Cherepovets, Russia, was successfully put into operation at the end of 2011 and production quickly increased in the following months. The new plant is of identical design to the SMS color coating line that went into operation at Severstal at the end of 2005.

Besides the very high process speed, the highlights of the line are the roll coaters and the high-performance drying ovens. In the future, a further 200,000 tons per year of hot-dip or electrolytically galvanized cold strip will be color coated in western Russia. The strips are mainly used in the construction and household appliances industries.

A backup roll coater is used to apply a primer on the surface, which is dried in low-emission catenary curing oven. Subsequently the strip can be coated with a finish coat in two back-up roll coaters and Two highly efficient ovens are integrated in each color hardened in another horizontal catenary curing oven. coating line to dry the primer coating and the finish coating.

Oven from the operator side. Drive side of the finish oven.

54 Shandong Nanshan, China

Color coating line for alumi- drying oven are perfectly harmonized.This ensures num can material high product quality and low consumption of resources SMS is supplying a color coating line to the Chinese and energy. aluminum producer Shandong Nanshan. The line will The solvents will be evaporated without any contact be designed for an annual production of 50,000 tons in a floatation oven, with the strip surface curing in of coated aluminum strip. The line is designed for the process. Along the entire furnace length, the strips with a thickness of 0.15 to 0.5 millimeters and strip will be uniformly heated by hot-air nozzles while widths ranging from 950 to 2,000 millimeters. The being carried by an air cushion in a floating position. material is intended to be used predominantly for the The fact that there is no mechanical contact between production of beverage cans. the strip and any part of the furnace guarantees an The highlight of the plant design is the compact coat- impeccable surface quality. ing and curing process. The chemical pretreatment The evaporated solvents will be combusted in a high- section, the subsequent strip coating process and the ly efficient thermal process in a regenerative thermal oxidizer (RTO). This solution makes it possible to heat-treat a wide range of products without any external energy input (autothermal operation).

The new color coating line of Shandong Nanshan features a powerful floatation oven to dry-out the color coating which is combined with an integrated regenerative thermal oxidizer system, that makes it possible to heat-treat a wide range of products in an autothermal operation mode (i.e. without any external energy input).

55 Aluminum Heat Treatment

Aluminum as light weight construction material for the automotive industry The use of aluminum as a light weight construction where it is guided sinusoidal in a contactless floating material in automobiles continues to be on the rise. mode. It is heated up and kept at the required strip Subsequent to the cold rolling process, the aluminum temperatures in time, so the aluminum-alloy obtains sheets have to under go a heat treatment to regain their structure. Especially 6xxx automotive-alloys as formability as well as the required material strengths. well as 2xxx and 7xxx aerospace-alloys require high Especially the heat treatment and the cooling of the cooling rates up to approx. 400 Kelvin per second. strip play a major role. This happens in combined The cooling process is executed as a combination of heat and chemical treatment lines or in single heat water and air cooling. treatment lines. A special feature of the furnace is the eco-friendly The furnace and cooling technology is the heart of process control. Operation is controlled by a physical the process. The strip enters a floatation furnace process under consideration of the mechanical properties model and a production planning model with physical transient state calculation.

Water cooling with a predefined cross-bow In the aluminum heat treatment furnace a water- quench ensures at the same time high cooling rates and good strip shape. Thus, high qualities are achieved. Controlled and stable cooling is ensured by a predefined cross-bow. A special sealing unit prevents premature cooling.

56 The heart of the new heat and chemical treatment line for Ma’aden-Alcoa JV is the powerful floatation furnace with water-quench unit.

Reference: Ma‘aden-Alcoa JV, Saudi-Arabia

Heat and Chemical Treatment Line for Automotive and Aviation Grades For a new continuous heat and chemical treatment One of the technical highlights of the line is the strip line at Ma’aden-Alcoa, all plant components including floatation furnace.The equipment paves the way for electrical and automation systems were supplied by Ma’aden-Alcoa to enter the market for aluminum SMS from a single source. SMS was responsible for car body sheets. The line is able to produce 60,000 the design, manufacture, erection supervision and tons of annealed,cleaned and chemically treated strip commissioning of the line in the Ras al Khair plant in material. In March 2015 the first aluminum coil was Saudi Arabia. successfully heated and chemically treated in the new line.

During cold rolling, the aluminum strip solidifies and necessary for thedesired mechanical properties, the must be annealed to regain its formability for further material is heated to approx. 560 °C, then rapidly processing. These lines also homogenize and solution- cooled in a controlled way. It is imperative that the anneal alloys that can solidify due to special inter- sensitive surfaces are not supported by rolls during metallic precipitates. To achieve the microstructure heating, which is where convection strip floatation furnaces come in. Furthermore,in a combined heat and chemical treatment line, (which is shown here) the strip receives a chemical treatment that prepares the surfaces for subsequent painting.

57 58 furnaces for slabs, bars and tubes

Every rolling mill is different and the same should apply to every furnace. The SMS furnace experts offer tailored solutions for any process and layout. The design capability includes in general the following furnaces.

Roller Hearth Furnaces page 58

CSP®-Roller Hearth Tunnel Furnaces page 62

Chamber Furnaces page 64

Walking Beam Furnaces page 66

Walking Hearth Furnaces page 70

Pusher Furnaces page 72

59 Roller Hearth Furnaces

Efficient heating of heavy one hand, the rollers are a decisive factor as regards plates the costs of such a furnace system, which again The roller hearth furnace is often used in a contin- depend to a large extent on the price fluctuations, uous heat treatment process for heavy plate. Its especially for the main constituents of Cr and Ni. On strengths are, on the one hand, different speeds for the other hand, the rollers may also impose restricti- the individual heat treatment of plates and, on the ons on the system design. A sufficient lifetime of the other, a high maximum speed, which is important, rollers can only be guaranteed if the hearthload as a in the first place, when it comes to transporting the combination of temperature, plate load per roller and plates to the quench. bearing center distance (which again is directly linked to the plate width) does not exceed certain limits. The furnace housing of a roller hearth furnace has the shape of a long tunnel. The hearth itself consists Heating is accomplished either by open or indirect of rollers arranged transversely to the direction of firing through radiant tube burners with the furnace transport. The distance between the rollers must not chamber being rendered inert by flushing with nitro- exceed a maximum dimension, as otherwise there gen. The indirect heating method results in less would be a risk of the plates “diving” below one of scale on the plates, but requires considerably higher the rollers. This maximum dimension is thus deter- investment and operating costs. The radiant tubes of mined by the bending behavior of the thinnest plate indirectly heated furnaces are equipped with recupe- at the highest possible temperature. The roller hearth rator burners. divides the furnace into a top and a bottom section For open fired furnaces, however, it is recommended which provides the possibility of heating from both to use high speed burners with a central recuperator sides. for preheating the air. The hearth usually consists of high-alloy centrifugal cast rollers and which is the core component. On the

Roller hearth furnace for normalizing and tempering Cross-section of a roller hearth furnace with radiant tube heating.

60 Reference: Acroni, Slovenia

Two roller hearth furnaces for special grades SMS delivers two roller hearth furnaces for the The roller hearth furnace for hardening and solution Slovenian steelmaker Acroni, which are integrated annealing will be equipped with two chambers, in into heat treatment lines for heavy plates. The fur- which the plates will be annealed in a nitrogen-based naces will be designed for 4 to 13 meter plates inert gas atmosphere. Heating to up to 1,100 °C will with thicknesses ranging from 3 to 100 millimeters be carried out indirectly using radiant heating tubes and a width ranging from 700 to 2,560 millimeters. with recuperator burners. The total furnace length is The maximum weight of the plates is 16 tons. The 33.6 meters. range of materials includes high-strength carbon The roller hearth furnace for tempering is only steels, stainless and tool steels as well as a range slightly shorter with a length of 32.3 meters. In this of special grades. open fired furnaces, however heating takes place SMS supplies a roller hearth furnace for hardening, via high-speed burners which heat the furnace up normalizing and solution annealing and another roller to 800 °C. The achieved plate temperature lies hearth furnace for tempering, as well as a quench- between 400 °C and 780 °C. ing system and all auxiliary facilities. These will include the complete plate conveying equipment, all systems for the water supply and water treatment as well as the automation of the systems.

Roller hearth furnace for hardening and normalizing.

61 CSP®-RolleR HeaRth TuNNel FuRNaCes

EFFICIENT HEATING AND SLAB TRANSPORT WITH SPECIAL COOLING ROLLS In the CSP® plant, the roller hearth furnace is the The downstream homogenizing zone keeps the tem- logistical and technological link between continuous perature at a constant level and harmonizes it over caster and rolling mill. The first zone of the more the cross-section and length of the slab to achieve a than 1,100 °C hot furnace serves to set the thin slab homogenous temperature distribution. This is neces- temperature required for the rolling process. This is sary for an optimized rolling process and makes sure achieved by using environmental friendly ultra-low the finished product is of high quality.

NOx burners. In order to save energy, the combustion To transport the thin slabs through the furnace, spe- air is preheated by waste heat from the furnace via cial water-cooled rollers are used. They ensure little recuperators. heat is dissipated and thus increase the energy efficiency of the furnace. To satisfy the high demands on the final product surface quality, a newly developed calculation module minimizes the contact pressure between roller support rings and slab.

A special Dynamic Furnace Control (DFC) level 2 process automation system is used in a CSP®-furnace to ensure heating of the slab to the required target temperature with good uniformity and without energy wastage (see page 18).

The slabs are transported through the furnace via cooled and wear resistant rollers.

Newly developed rolls with fireproof aluminum silicate wool.

62 Reference: Big River Steel, USA

CSP®-roller hearth tunnel furnace in a new integrated steel plant For the new steelworks of Big River Steel, SMS end product. Already in place are plans for producing group will supply all thermal processing equipment. sophisicated products that cater to the demands of Thus, the complete know-how for heating and cool- the growing market-products such as pipe grades for ing throughout the whole processing chain is supplied pipelines, AHSS grades, and especially silicon steels from one source and ensures high material quality is for electrical sheet. That's why the CSP®-Furnace is attained. In the first stage, the new complex of Big designed from the start for slab temperatures of up River Steel in Osceola, in the state of Arkansas, USA, to 1,220 °C. will produce 1.5 million tons of hot strip. Part thereof This includes water-cooled furnace rollers with fire- will be refined in-house to produce high-strength cold proof insulation made of aluminum silicate wool. strip for automotive applications. Thus, higher temperatures are possible at low energy The CSP® plant is capable of producing strips with losses via the cooling water. Still to come is an thickness ranging between 1.55 - 25.4 millimeters. expansion stage that will substitute the final section Equally impressive is the strip width of up to 1,930 of the tunnel furnace with a muliple module induction millimeters, which means Big River Steel owns the heating system. Carrying out this conversion means world's widest CSP® plant. The CSP®-roller hearth it will be possible to increase the slab temperature furnace features a newly developed calculation mo- from 1,220 °C to the level of 1,320 °C, required for dule to minimize the contact pressure between roll the most difficult-to-produce steels. carrier rings and slab for high surface quality of the

63 Chamber Furnaces

Batch operated furnaces with a fixed hearth Chamber furnaces are batch-operated furnaces with furnace and discharged from the furnace by means a fixed hearth. These furnaces are characterized by of a machine. For plate transfer to the furnace and their high degree of flexibility and are thus typically away from the furnace, a conventional roller table is used in the case of low capacity requirements and installed along the longitudinal side of the furnace. frequently changing batches. Depending on the case The chamber furnace is often used for normalizing of application, the hearth can be subdivided such that or solution annealing at elevated temperatures in heating of the plate bottoms can be implemented at the case of high plate loads and large plate widths. least in parts of the furnace. On the longitudinal side, Concerning the combination of plate load and tempe- the furnaces are equipped with a large door. Through rature, this furnace has almost no restrictions. this door, the plates are introduced into batch type

With the help of loading machines all plates are introduced separately into the batch type furnaces.

The large doors on the longitudinal side of the furnace opens and a glowing plate is discharged out of the furnace.

64 Solution annealing takes place via high-speed burners in the open fired batch furnace at Outokumpu.

Reference: Outokumpu, Sweden

Two chamber furnaces which can be connected As part of a complete heat treatment line, SMS deli- times, provided that the separation gate is closed. vered two chamber furnaces to Outokumpu Stainless This offers a high degree of flexibility and thus in Degerfors, Sweden. The two batch-type were deli- optimal hearth utilization at all times, which guaran- vered completely with charging machines and con- tees energy-efficient plant operation. In this way, necting roller tables as well as all the accompanying Outokumpu can occupy a furnace with either one electrical and automation equipment. long plate or two short plates.

The new furnaces are used for heavy plates and high The batch type furnaces can heat plates to more than heat-treatment temperatures, as well as for small 1,200 °C. With such high temperatures, Outokumpu batch sizes of niche products. The loading machine is capable of manufacturing sophisticated steels such introduces a stainless steel plate into the furnace. as high-alloy grades for special applications.The The furnace plant consists of two batch type fur- furnaces meet the high environmental protection naces, both of which have two doors. The reason for requirements and are equipped with a modern heat- this is that every furnace can be further divided into recovery system. A further special feature is the pro- two chambers using a special separation gate. In this cessing of very thin plates. The plate lengths range way, Outokumpu can occupy a furnace with either from 3,000 to 16,000 millimeters and the widths one long plate or two short plates. If two plates are from 400 to 3,500 millimeters. The loading and un- in the furnace, then these can be heat-treated indi- loading machine conveys at approximately 2 meters vidually using differing annealing temperatures per second.

65 WALKING BEAM FURNACES High productivity combined with operational flexibility

Walking beam furnaces, both top and bottom-fired, FAST AND RELIABLE MATERIAL allow for high production rates and top quality steel HANDLING MACHINES grades. Billets, heavy blooms, slabs and beam blanks SMS sturdy discharging machines avoid any misalign- can be charged. Walking beam furnaces feature ment in the discharging area, even when handling many cooled elements as well as special alloy parts workpieces of very different sizes and shapes. They which endure high temperatures and mechanical virtually eliminate vibrations and positioning errors. stresses. SMS group continuously works on the The possibility of reverse movement in emergency development and integration of new designs and situations as well as the choice of manual handling materials. Thanks to the advanced combustion sys- are further key advantages. SMS group offers a wide tem, all SMS walking beam furnaces are highly flexi- range of kick-in and kick-off machines, both electro- ble in operation. mechanically and hydraulically operated – so even the most challenging demands are met.

66 RAPID DISCHARGE RATE The record-setting machine delivers one billet every 24 seconds. It is installed in the high-capacity walking beam furnace at KSC Nizhneserginsky Metizno- Metallurgichesky Zavod – ZAO “NSMMZ”.

BENCHMARK EFFICIENCY The 180/220 tons per hour walking beam furnace at United Steel Company, Bahrain, is equipped with ultra-low NOx burners. It sets benchmarks in efficiency and low emissions.

67 68 HIGH QUALITY MEETS LOW ENERGY CONSUMPTION

ArcelorMittal Ruhrort operates one of the world's furnace. The waste gas evacuation system is equip- most modern wire rod mills. The plant was supplied ped with special filter units which effectively reduce by SMS group and produces a wide range of special the release of particulate matter.The walking beam steel grades for the premium market, primarily the geometry guarantees perfect overall heating quality: automotive sector. The walking beam furnace Faster reheating ensures better control of decarbu- adequately supports the slender billets with the fixed risation, vital for high-quality rods. and movable skid. The result: 110 tons of billets with a thickness of 155 millimeters and a length of 16.5 The temperature homogeneity is enhanced by a meters are optimally heated every hour, meaning large battery of low-NOx radiant burners in the ArcelorMittal can reliably deliver premium quality pro- heating and soaking top roof, and by the digitally ducts. The double-stage recuperative system allows controlled long-flame burners installed in the bot- for benchmark efficiency and minimum emissions: a tom soaking zone. specific natural gas consumption of 250 kcal/kg and less has been achieved very early after lighting of the

69 WALKING HEARTH FURNACES Minimum specific consumption figures

Walking hearth furnaces are the optimum choice for advantage of this furnace type is that it allows for many long products mills with production rates of up very low specific consumption figures, achieved to 140 tons per hour. Due to the layout with top heat- thanks to the absence of water-cooled elements ing only, these are recommended for products with inside the furnace. a maximum thickness of 160 millimeters. A major

70 RECORD-BREAKING PERFORMANCE: 16 M SLENDER BILLETS UNDER A RADIANT ROOF Stefana S.p.A. set up a 700,000 ton per year bar mill burners guarantees optimum temperature homo- under a project entitled “Dream Steel”, located in geneity of the reheated workpieces. Ospitaletto, Italy. The furnace specialists designed The heat maintenance zone, a series of small burners a furnace capable of reheating billets with a length that retain the furnace temperature during weekend of 16 meters, with the result that Stefana can profit stoppages and prolonged mill downtimes, helps from the market demand for large coils with a weight Stefana to reduce energy costs. The reheating fur- of more than three tons, as well as from the overall nace is able to supply the mill with a continuous out- benefits of improved yield. This target was achieved put of 120 tons per hour starting with cold billets, or by constructing a walking hearth furnace with a sus- 140 tons per hour when hot charged. pended 16.8 meter wide roof. A battery of 90 radiant

71 PUSHER FURNACES Low investment costs combined with robust design

When it comes to heavy duty and straight forward design furnaces for billet reheating, the pusher type furnace is often the perfect choice. Pusher furnaces are typically suitable for low-production mills for common steel grades, for example rebar mills.

ADAPTABLE TO VARIOUS NEEDS Top-fired pusher type furnaces combine the benefits of a sturdy construction and simplicity in design with low consumption. Top and bottom-fired pusher type furnaces are capable of high production rates. Pusher type furnaces are an inexpensive alternative to more sophisticated walking hearth furnaces or walking beam furnaces for the production of simple products.

72 FIELD OF APPLICATION: LONG PRODUCTS Larger furnaces for greater profit

SMS group has decades of experience in the design even longer billets – the engineers can deliver what- and construction of rolling mills for bars, sections ever their business partners need to improve their and wire rod. The same goes for reheating furnaces. competitiveness. Over the years the furnace experts have developed The demands in terms of heavy section mills and rail many benchmark solutions to meet the increasing mills are similar: by using starting blooms longer than demands of the long products market. the traditional 12 meters, the plant owners profit One example is the ability to produce coils which from increased metal yield by reducing crop ends. have a weight of 3 tons and more and a higher market value per ton. For this purpose, billets much longer than the traditional 12 meters are used as starting stock. Billets above 12 meters in length are the market standard today. SMS group offers furnaces for

73 FIELD OF APPLICATION: FLAT PRODUCTS Reheating furnaces for optimum slab quality

SMS group offers highly productive walking beam QUICK COMISSIONING, SHORT furnaces for slab reheating with capacities of up to CYCLE TIME 400 tons per hour. They are equipped with a set of The enormous kick-off machine for a 30 ton fixed and movable water-cooled skid beams. In order slab treatment furnace at Outokumpu in to minimise skid marks both fixed and movable skids Degerfors, Sweden, was preassembled in the are staggered between the heating and the soaking SMS group workshop area. Heat losses through the cooling water are mini- to ensure a minimum mised using composite double-layer insulation for the commissioning time. complete skid system. Cycle times are short too: the machine can HIGH QUALITY THROUGH OPTIMISED unload one slab every TEMPERATURE DISTRIBUTION 20 seconds. A set of special alloy skid riders is placed on top of the fixed and movable skids over the entire length of the furnace chamber. The furnace engineers calcu- late the height of the riders precisely so the slabs are at a sufficient distance from the water-cooled skid. The results: skid marks and dark spots on the slab are minimised as the temperature of the skid’s contact spot is very close to the temperature of the heated slab.

74 WIDE RANGE OF COMBUSTION SYSTEMS SMS group equips all walking beam furnaces with highly efficient, digitally controlled combustion systems and conventional, hybrid or fully regenerative burners that work using all widely available fuels.

SMALL IN CAPACITY BUT GREAT ON FLEXIBILITY SMS group also offers special walking hearth furnaces for small slabs. These compact solutions are characterised by smart loading diagrams which allow high loading flexibility. They process a wide range of slab sizes and thicknesses.

75 FIELD OF APPLICATION: PIPES AND TUBES Fully integrated furnaces for any process

Tube rolling is one of SMS group core competencies. ally adapts the technically sophisticated systems to The know-how accumulated by the heating technol- the specifics of every single mill, such that even spe- ogy experts is extensive: they know every detail of cific process requirements are optimally met. Plant the production process and can handle even critical operators benefit from a smooth production process reheating profiles. and optimum tube quality.

SPECIALISTS IN TUBE ROLLING, SMS has designed and constructed some of the REHEATING AND HEAT TREATMENT most advanced and largest rotary hearth furnaces in SMS combines the benchmark-setting Premium the world. They combine high capacities with special Quality Finishing (PQF®) mills for producing seamless materials and components for maximum temperature tubes with high-end furnaces. Advanced combustion endurance. That’s why for decades SMS furnaces systems guarantee complete temperature uniformity have been able to withstand the high temperatures and minimum energy consumption. The rotary hearth typical for this process – and plant operators have furnaces as well as the shell reheating furnaces are been able to minimise maintenance costs. fully integrated into the rolling process. SMS individu-

76 SHELL PIPES WITHIN A 5 °C TEMPERATURE RANGE SMS walking beam furnaces bring shell pipes to the required temperature with maximum precision before final sizing. Thanks to advanced combustion control systems, the furnaces achieve a temperature tolerance deviation of only ±5 °C, more than sufficient for overall mill process control and thereby ensuring the final tube quality.

77 INTELLIGENT ENERGY RECOVERY Whenever SMS engineers design a plant, they con- sider the whole production process and combine the individual process stages to produce the best results for their business partners. One example is the further utilisation of the heat energy that exits the rotary hearth furnace, which is by far the most energy-demanding unit in a seamless pipe mill. Using a completely automated fume recirculation system, SMS rotary hearth furnaces satisfy all the energy requirements of the mandrel reheating furnace. Plant operators save all energy costs for mandrel reheating and reduce emissions here to zero.

ZERO EMISSIONS AND ZERO ENERGY CONSUMPTION The energy required for the mandrel reheating furnace is fully obtained by exploiting the excess heat from the rotary hearth furnace exhausts.

78 79 FIELD OF APPLICATION: FORGED PRODUCTS Furnaces as versatile as the product mix

SMS group has set new standards in forged product THE FORGE MILL FURNACE AT reheating, in terms of both operational flexibility TOSCELIK and reheating efficiency. The furnace experts trans- The furnace for heavy blooms and ingots at ferred and optimised the comprehensive experience Toscelik, Montenegro: a single motorised gained to high-productivity rotary hearth furnaces for machine, swivelling on a 25° arc, handles both pipe mills. On this basis, they developed advanced charging and discharging. dedicated reheating solutions for forging plants. With SMS group furnaces, forging plant operators gain a competitive edge due to increased productivity and a wide product mix combined with reduced energy and maintenance costs.

FLEXIBLE, EFFICIENT AND COST- EFFECTIVE An impressive example of the SMS approach is the new type of rotary hearth furnace: it is charged and discharged through two separate doors by a single elevated-type swivelling machine. This design, combined with state-of-the-art combustion and control systems, allows for the perfect combination of high

80 energy efficiency and proper operational flexibility. wide product range: multi-chamber furnaces which At the same time, plant operators benefit from low allow for simultaneous heating of different products investment and maintenance costs. at different temperatures. In these highly flexible furnaces every product is heated precisely according ONE FURNACE, MULTIPLE to its specific requirements. The temperature zones TEMPERATURE ZONES are regulated by a digitally controlled single combus- SMS group developed a special furnace design for tion system. Regenerative burners guarantee high forging plants with small to medium capacity and a efficiency,

MULTI-CHAMBER FURNACE One control system, multi-stage heating: the capability of three separate furnaces combined into one.

81 82 HEAT TREATMENT OF HOT-FORMED MATERIAL

Highly demanding applications require exceptional qualities guaranteed for every single plate, tube or bar. SMS’s heat treatment specialists design and construct benchmark setting heat treatment solutions combining the sophisticated heating technology with advanced and proven cooling systems.

Heavy Plates page 82

Tubes and Pipes page 92

Bright Tubes page 100

Bars page 102

83 Heavy Plate Heat Treatment Lines

Different process routes for The result of the quenching process is a significant heat treatment of hot-rolled increase in hardness due to the formation of mar- heavy plates tensite. Plate fixing during the quenching process SMS group has been focusing on heat treatment ensures good flatness even at high cooling rates. technology for heavy plates and hot strip to make Whereas a continuous quench cools the plates on production processes more efficient and flexible. The their way through the line, a platen quench or a development of new materials and changing market discontinuous roller type quench cools in batches environments caused a demand for flexible plant plate by plate. Due to their lower throughput, they solutions concentrating on material quality. The are economic solutions especially for low production solutions permit a wide range of heat treatment strat- volumes. A new type of quench is the newly devel- egies for a great variety of materials. oped MultiFlex-Quench® which is no longer rigidly subdivided into a high-pressure and a low-pressure To produce plates with ever higher strength and section. Instead, the entire range of cooling rates is toughness, plant technology must undergo con- available over the full length. tinuous advancement. New rolling and cooling technologies often allow the mechanical properties to be Electrical and automation set within the rolling line, but extremely challenging systems materials, however, require a final heat treatment in a For the effective setting of mechanical properties in special heat treatment line. heat treatment, SMS integrates its X-Pact® electrical and automation systems also in these plants. To The type of furnace normally used in a continuous describe the complex and, in part, highly dynamic heat treatment process for normalizing and temper- processes, mathematical models are used and com- ing is the roller hearth furnace. Its strengths are on bined to a holistic approach. The essential target the one hand different speeds for individual heat values for plant control are mechanical properties treatment of plates and on the other hand a high (respectively the microstructure), energy efficiency maximum speed to transport plates to the quench. and plate flatness. Calculation of the cooling rates For the heat treatment of stainless and special which determine the material properties is made on steels, double walking beam and chamber furnaces the basis of SMS’s material data base which is the are also frequently used. foundation of all SMS group process models. For all In the face of changing energy costs and rising steel grades it provides the most important physical environmental requirements, SMS attaches great and mechanical properties depending on their chemi- importance to high energy efficiency in the rating cal composition and temperature. and design of the furnaces. For each project, SMS develops a tailor-made optimum solution in cooperation with the customer, taking into consideration upstream plant areas.

84 Furnaces for Heavy Plate Heat Treatment

Discontinuous Continuous Operation Operation

Double Walking Chamber Furnace Roller Hearth Beam Furnace Furnace (Normalizing)

Open Protective SMS offers different heating Atmosphere Atmosphere solutions for heavy plate heat treatment lines.

SMS is able to deliver complete heat treatment lines systems for heavy plates with different furnaces and quench types as well as all auxiliary equipment (incl. electrics and automation, water treatment plant, handling and transport systems, cooling beds, levelers).

85 Heavy Plate Heat Treatment Lines – Roller and platen quench

Quenching of heavy plates cooling intensity. Furthermore, as soon as water is Plates can be quenched in two different types of applied in the case of a platen quench, differences in quenching units. One of them is the batch-operated temperature will occur between plate head and tail so called platen quench. If this quenching station ends that due to the plant‘s discontinuous operation is used, the plates are stopped after their rapid dis- cannot be entirely avoided. charge from the furnace and clamped by means of For both types of quenching machines, the actual clamping jaws. After clamping, water is applied by quenching process is characterized by very high means of nozzle pipes, which are arranged above dynamics. In doing so, extreme cooling rates are and below the plate. implemented by means of enormous amounts of For continuous operation so called roller quenches water and special nozzle systems. Monitored and are used. In this case, the plates pass through the controlled by the plant automation systems, cool- plant without being stopped. The major advantage ing must take place homogeneously across the of the continuous roller quench as compared to the entire length and width of the plate, since even the platen quench is the possibility of using individual smallest variations in the cooling conditions may stages with different cooling rates and the associated result in flatness deviations and warped plates. implementation of a short section with a higher

In a roller quench the heavy plates are cooled down with water while achieving high cooling rates.

86 Reference: MKK, Russia

Roller pressure quench The roller pressure quench provided by SMS helps system for austenitizing lines MMK to excel in the areas of cooling speed and The roller pressure quench has been delivered flatness while using less energy than the previous to Magnitogorsk Iron and Steel Works (MMK). systems. Thanks to the use of lower pressures in the Commissioning of this system took place in 2010. high intensity section, the quench system attains the required cooling performance while consuming less energy than conventional installations. This provides substantial savings in operation costs. Improved roller design ensures better uniformity over the width of the strip. In the spray lines situated above the metal, an edge masking system limits water consumption to the quantity strictly necessary for the width of plate concerned.

The quench for MMK treats plates with a thickness between 8 and 60 millimeters and a width of 1,500 to 4,650 millimeters. The plates with a length of 6 to 20 meters are mainly used in the construction or ship building industry.

Reference: Acroni, Slovenia

New quench for larger Due to higher cooling rates, the new quench opens product spectrum up new possibilities for the extension of the product In January 2013, Slovenian steelmaker Acroni com- scope (e.g. in the range of Duplex grades). To avoid missioned a new multimedia roller quench supplied different temperatures between the top and bottom by SMS. To be able to extend the product range, side of the plate, the quench is equipped with spe- especially for thin and wide plates and to improve cial cooling headers, which control the water flow to plate quality, Acroni invested in a new 2.6-meter ensure homogeneous cooling. At the same time they heavy plate mill stand and a new multimedia roller prevent the formation of flatness deviations on thin quench. The supply scope concerning the quench plates. In addition to the high cooling rates by water consisted of the supply and the installation of the cooling, the quench is also able to slowly cool down new quenching device, a new pump station, the grades like tool steel by air. Here, plates are cooled interconnected piping, as well as a new electrics and down by air until a critical temperature is reached, automation system. The new quench is designed for and then the faster water cooling starts. plates up to a width of 2,560 millimeters and a thickness between 8 and 130 millimeters.

87 Heavy Plate Heat Treatment Lines – MultiFlex Quench®

New technology for more ferent heat treatment steps are integrated into the flexibility automation systems to optimize the process param- SMS developed a new type of quench, the MultiFlex- eters. Based on this know-how, it will be possible Quench®. Contrary to conventional continuous to set the mechanical properties achievable by the quenches, this type is no longer rigidly subdivided heat treatment more precisely, minimize the use of into a high-pressure and a low-pressure section. alloying elements, shorten process times, increase Instead, the entire range of cooling rates is available the output and hence contribute to environment pro- over the full length. All cooling patterns from slow tection. cooling to abrupt quenching can thus be realized to Exact control of the cooling achieve an even wider product portfolio. By install- process via proven level 2 ing different nozzle systems and control valves, the model MultiFlex-Quench® can be individually designed to Precise setting of the mechanical properties suit the customer’s product mix. Minimized use of alloying elements SMS also assists customers in determining the optimum heat treatment parameters to new high-quality Short process time plate products on the MultiFlex-Quench®. Material Increased output properties such as time-temperature transformation characteristics or mechanical core values after dif- Environment friendly production

The MultiFlex-Quench® offers the highest flexibility for heavy plates with variable pressure sections and an optimized plate flatness due to active hydraulic clamping via pinch rolls.

88 Plate data (level 2) Online temperature data Physical reference values

SMS cooling model

Process parameters

The process parameters are calculated automatically which ensures an exact control of the cooling process.

Accelerated cooling (ACC)

Quenching (DQ)

Quenching/

Temperature self tempering (Q+SA)

Core Temp. Sensitive cooling/ Surface Temp. accelerated cooling (SQ) Martensite Start Temp. Time

The newly developed solution offers a wide process window which allows all cooling patterns from slow cooling to abrupt quenching.

89 Heavy Plate Heat Treatment Lines: References

Reference: Outokumpu, Sweden Heat treatment line for flexi- treated simultaneously in the quench. The automation ble and efficient stainless system for the entire heat-treatment line was also steel plates implemented by SMS. This includes all material- SMS group delivered a heat treatment line for stain- tracking in the individual plant components and on less steel plates to Outokumpu Stainless in Degerfors, the roller tables, as well as the furnace recipes and Sweden. This expansion allowed Outokumpu to the quench's cooling strategies which are coordinated boost its production of heat treated plates and im- with them. This ensures that all plant components prove the product quality. are harmoniously coordinated with each other when it comes to the heat treatment processes. As an addition to the existing line, which consists of a rolling mill, a roller-hearth furnace and a quenching device, SMS has erected a new line for heat treatment in parallel. The line essentially consists of two batch type chamber furnaces with charging machines, a roller quench, the connecting roller tables, the water supply and treatment system and all the accompanying electrical and automation equipment. As regards process engineering, the new line has been integrated with the cooling bed and the cold plate leveler, also supplied by SMS. As the line is directly connected to the rolling mill, it is possible to feed the plates into the furnace or the quench at rolling temperature, by way of hot charging. The plate length ranges from 3,000 to 16,000 millimeters The plates are heated up discontinuously in two chamber and the widths from 400 to 3,500 millimeters. furnaces. The batch-type furnaces can heat plates to more than 1,200 °C. With such high temperatures, Outokumpu is capable of manufacturing sophisticated steels such as high-alloy grades for special applications. The furnaces meet the high environmental protection requirements and are equipped with a modern heat-recovery system.

In the quench, the plate is guided between the rollers positioned above and below. The upper and lower spraying headers use water to quench the whole width of the plate at a precisely defined cooling rate. Oscillation of the plate makes for an optimal and uniform cooling process. Two plates can be

Subsequent cooling takes place in a roller quench unit.

90 The MultiFlex-Quench® ensures a high degree of flexibility when it comes to different cooling strategies for heavy plates.

Reference: Acroni, Slovenia World’s first MultiFlex- annealed in a nitrogen-based inert gas atmosphere. Quench® for heat treatment Heting to up to 1,100 °C will be carried out indirectly of heavy plates using radiant heating tubes. The innovative MultiFlex- The Slovenian steelmaker Acroni has placed an order Quench® is characterized by its exceptionally with SMS, to deliver a heat treatment line. As part high degree of flexibility. It sets itself apart from of the heat treatment line, SMS will for the first time other quenches by the extremely wide range of install the newly developed MultiFlex-Quench®, which cooling rates, from abrupt water quenching right offers an outstandingly high degree of flexibility and down to gentle cooling, achieved by a multiple nozzle high cooling efficiencies in the heat treatment of systems. As a result, flexible cooling patterns are heavy plate. possible for a wide range of different steel grades. Squeezer rolls fix the plate in place and hence en- The line will be designed for plates with thicknesses sure good plate flatness, even at high cooling rates. ranging from 3 to 100 millimeters; the range of Following the MultiFlex-Quench®, the plates can be materials includes high-strength carbon steels, tempered in an open-heated roller hearth furnace at stainless and tool steels as well as a range of spe- temperatures between 400 °C and 800 °C. cial grades. For the new line, SMS supplies a roller hearth furnace for hardening and normalizing, a quench of the MultiFlex design and a roller hearth furnace for tempering, as well as all auxiliary facilities. These will include the complete plate conveying equipment, all systems for the water supply and water treatment as well as the automation of the systems. The hardening furnace will be equipped with two chambers, in which the plates will be

91 HEAT TREATMENT of Tubes and Pipes Premium quality pipes that satisfy even the most demanding requirements

Over recent years, the tube industry has enjoyed a boost from the worldwide upturn in oil and gas exploration. Deeper conventional wells and non- conventional oil and gas exploration require a huge number of quality tubes which are often exposed to extreme conditions. In this field, the failure of one single pipe can make the difference between a highly profitable business and a considerable money loss.

To guarantee the high quality and desired mechanical properties required for Oil Country Tubular Goods (OCTG) applications, sophisti-cated heat treatment is necessary. The pipes must be heated and cooled in accordance with strictly controlled process cycles.

92 IN-DEPTH CONTROL FROM SINGLE TUBES TO PROCESS OVERVIEW An intelligent tracking system ensures traceability of each tube through the line. It enables tracking of the heat treatment performed on the single tube lots, in order to keep a record of the achieved results.

The production input mask Layout overview Each lot or tube can be identified and assigned to a The operator can monitor the functionality of every specific heat treatment recipe. single machine and control the position of any workpiece inside the plant.

93 Century long experience in DESIGN FEATURES FOR PREMIUM seamless tubes production TUBE QUALITY SMS group has already more than 125 years of expe- SMS hardening and tempering furnaces guarantee rience in the production of seamless tubes: Its roots the tightest temperature tolerances. This is how go back to 1885, when brothers Reinhard and Max plant operators can ensure consistent properties over Mannesmann obtained the first patent for the manuf- the whole tube length. In most cases, the furnace acture of seamless tubes – a pioneering invention. In specialists install high-speed burners that generate the past 50 years alone SMS group has implemented strong turbulence inside the furnace chamber. The over 2,000 seamless tube plant projects. result is a consistent and homogeneous skin temperature which leads to homogeneous mechanical HEAT TREATMENT: THE COMPLETE properties over the whole pipe length and cross- RANGE section. The heat treatment specialists complement the company’s tube rolling expertise with a wide range EFFICIENT HANDLING SYSTEMS FOR of advanced heat treatment plants, from quenching A SMOOTH PROCESS and tempering through normalising to annealing. SMS individually designs the pipe handling equip- SMS group offers benchmark solutions like the SMS- ment for each heat treatment line. The fully integrat- Quench® system, which enables pipe manufacturers ed systems guarantee a proper material flow that to achieve the desired quality and to enhance process avoids any bottlenecks. Scratch-free pipe handling consistency from the billet to the pipe fit for sale. machines help to prevent defective tubes.

94 PRECISE TEMPERATURE FOR INCREASED TUBE QUALITY

Combining a well-engineered furnace with a fine-tuned combustion system is the key to maximum precision: the discharge temperature of a whole tube lot, measured by pyrometer, demonstrates that the surface temperature is kept con- sistently within a narrow range of a few degrees.

MINIMUM NOX EMISSIONS Self-recuperative burners, available in both visible flame and flameless configurations, minimise NOx emissions.

95 SMS-QUENCH® When it comes to adding value to the pipe

To achieve the desired structure transformation developed by specialized SMS metallurgists, every effectively during the quenching process, it is essen- tube manufacturer benefits from a tailor-made cool- tial that the cooling down parameters are accurately ing system that fully covers the specific quenching controlled. Especially when it comes to OCTG pipes, requirements of any tube size and steel grade in the deviations from the demanding mechanical properties product portfolio. dictated by the relevant norms cannot be tolerated. Despite the fact that single tubes differ from each The difference between a premium quality pipe and other before heat treatment, SMS quenching a failure often comes down to just a few seconds or machines guarantee a predictable, properly controlled degrees. With SMS-Quench®, tube manufacturers and repeatable process that generates the targeted can reliably control and monitor all quenching param- quality precisely. This is especially important as even eters and thus adjust every tube’s qualities with the slightest difference in the chemical composition maximum precision. may lead to wide variations in the final properties. TAILOR-MADE QUENCHING ALWAYS RIGHT ON SPOT SOLUTIONS The quenching head is the core element of SMS- SMS-Quench® is an integrated system individually Quench®. It is one of the most effective solutions designed for each tube plant. Based on bain curves

96 QUALITY GUARANTEED The temperature-time-transformation function for a martensitic structure guarantees that the P110 grade, as stipulated in the API standard, is reliably met.

97 OPTIMUM QUENCHING OF THICK-WALLED TUBES and bars The SMS quenching tank and the new-born SMS quenching shell are fully automatic units, dedicated to the treatment of heavy tubes and solid bars. The SMS tank includes rollers to guide the tube and special stainless steel clamps to firmly hold it in position. The SMS shell is a synchronous quenching system where the workpiece is constantly kept spinning during the water spraying.

98 available for outside quenching and guarantees a fail-proof process. The quenching head is a ring-type PRECISELY THE QUENCHING device which allows for automatic regulation of the RESULTS YOU NEED spray nozzles’ angle according to different pipe out- The quenching head is the heart of the SMS- side diameters. It also automatically aligns the pipe Quench® system. It features over 1,100 stainless pass line with the head axis. This ensures that the steel nozzles per module to ensure maximum water streams strike the pipe in the direction of cooling uniformity. The ideal geometry and work- travel. The SMS-Quench® system also accurately ing parameters for the desired quenching result controls water pressure and flow and thus ensures are determined via CFD analysis. the desired depth and uniformity of the martensitic structure. A sophisticated automation system is a key process feature: the quenching head set-up parameters are managed automatically by the control system of the upstream austenitising and hardening furnace.

SMS-Quench® also features devices such as the quenching lance for internal pipe quenching and the quenching tank for treating heavy-walled pipes by complete submersion.

HIGH PERCENTAGE OF MARTENSITE EVEN IN LOW CARBON STEEL When treating low carbon steel grades, which are often used for welded tubes, a considerable and well directed water flow is necessary from the very first sprayer module. This is the only way to ensure a fast transformation and thus a high percentage of martensite. The results tube manufacturers achieve with SMS Quenching Head speak for themselves: the Grossmann quench severity factor, the so called “H-factor”, is reliably above an index of 2.

99 Tube bright ANNealiNg LiNes

Tube annealing in a protecTive an exit tunnel and an exit purge. Further important gas atmosphere components are atmosphere analyzing and control Tube bright annealing lines are used to produce systems. tubes made of stainless steel, nickel and titanium In the heating and soaking section the tubes are alloys (e.g. Inconel). In these lines annealing takes heated up to more than 1,000 °C and soaked for place in an oxygen-free, inert atmosphere with high several minutes. The section consists of an electri- hydrogen content. The tubes are characterized by cally or gas heated muffle. A newly developed system a shiny, reflective appearance and a high corrosion improves the mesh belt transportation inside the resistance. Typical areas of application are nuclear muffle. This system uses ceramic rolls. It increases and power plants, aerospace industry or chemical the lifetime of the mesh belt, reduces furnace stops processes and some other areas where, in addition for maintenance and last but not least minimizes to the characterisics of the material itself, high-grade, surface defects during thermal processing. Especially reflective surfaces and increased corrosion resist- the last point is very sensitive to process final ance are required. Inconel 690 tubes for nuclear application. The lines are designed for tubes in a length up to The heat treatment process takes place in a protec- 30 meters and diameters up to 60 millimeters. Tube tive atmosphere (pure hydrogen, hydrogen/nitrogen- thickness is up to 6 millimeters. Three different types mix or argon depending on the process). At both, of furnaces can be integrated in these lines: mesh entry and exit section of the furnace, two heaters belt furnaces, multi muffle furnaces or roller hearth are installed to ignite and burn the atmosphere gas furnaces. escaping from the tunnel. This is for safety reasons. Since the mesh belt furnace offers several advan- CONVECOOL system for high tages, this type is normally integrated in lines built speed cooling by SMS. The main advantage of this furnace is the The slow cooling section provides a buffer zone minimal risk of tube defects. This is very important between furnace and rapid cooling section to because the tubes are often used for safety relevant achieve stable pressure distribution. Furthermore, it parts and subject to intensive quality checks where is responsible for initial cooling of the belt and work even minimal failure leads to rejections. Furthermore, load by means of a water jacket so that the cooling high and controlled cooling rates can be applied. in the rapid cool section is alleviated. Mesh belt furnace with im- The function of the CONVECOOL rapid cooling sec- proved mesh belt trans- tion is to cool down the belt and tube load to their portation system final temperature to achieve required mechanical The line consists of a charging table with fixed rollers properies. It utilizes the principle of convection cool- to carry the bundles (set of tubes) to the entry tunnel, ing with recirculated atmosphere gas. High velocity a heating, soaking and cooling section as well as convection impingement allows the cooling down

Exit Purge Charging Jet Cool Table Heating Entry Exit Tunnel Tunnel

100 of the tube temperature rapidly and uniformly from The system is a single zone unit. The cooled atmo- annealing temperature to below 400 °C. The system sphere gas is discharged at high velocity to impinge provides the best product quality while at the same on both top and bottom of the load through a pair of time using less space for cooling than conventional slot type plenums. The returning gas will be cooled systems (water jacket cooling). down by the gas-water exchanger before entering to the recirculating fan.

Several references worldwide 12 Tube Bright annealing lines delivered SMS delivered altogether 12 tube bright annealing lines mostly with mesh belt furnaces, but also with roller hearth furnaces. Most lines have been delivered to customers in Europe (France, Sweden, Germany, Czech Republic) but there are also references on the Asian continent (China, Turkey). The last two lines were delivered in 2010 to Vallourec, France. These lines feature mesh belt furnaces, CONVECOOL cooling system and the improved mesh belt transportation system. Vallourec became world's first supplier to hold NSQ-100 certification (Nuclear Safety and Quality Management System), which is considered to be the strictest standard of its kind worldwide.

For Baosteel, China, a tube bright annealing line with mesh The CONVECOOL cooling system reaches high cooling rates melt furnace was erected in 2009. due to convection cooling with recirculated atmosphere gas.

For safety reasons the escaping atmosphere out of the A mesh melt furnace is the best choice for the production furnace is burned at entry and exit section. of tubes where surface quality is crucial, which is mandatory for most bright annealed tubes. 101 HEAT TREATMENT OF BARS

NOT ONLY TUBES REQUIRE HEAT TREATMENT Solid bars for numerous different applications need to be hardened, quenched, tempered or annealed to improve their mechanical properties. SMS offers a full range of different heating solutions ranging from bogie to tunnel furnaces to the more productive walking beam furnaces, always coupling the combustion expertise with a smooth design of the complete process line.

102 TOP CUSTOMERS DESERVE GROUNDBREAKING SOLUTIONS Working together with the worldwide top players in special steel production has always been a key to SMS for being at the avantgarde of innovation.

SMS designed a new heat treatment directly con- controlled sequence, managed by the SMS Controlled nected to the rolling line, enabling for the first time to Cooling Technology (CCT®) simulation model. treat bars up to the range of 250 millimeters without The core of the line is represented by a high-alloyed stopping the process and saving a large proportion of skids walking beam furnace, equipped with self- the heating energy. Stainless, acid and heat resistant recuperative burners to enhance the energy saving, steel as well as high-grade structural or tool steel are and by a tailor made Quenching Head. produced, each deserving a heating/cooling precisely

103 SMS group GmbH Drever International SA Processing Lines and Furnace Technology Allée des Noisetiers 15 Eduard-Schloemann-Strasse 4 4031 Angleur (Liège) 40237 Düsseldorf Belgium Germany Phone: +32 4 366-62 62 Phone: +49 211 881-5100 Fax: +32 4 367-76 78 Fax: +49 211 881-4212 [email protected] [email protected] www.drever.be www.sms-group.com

SMS group S.p.A. Ares Industrial Furnace (Tianjin) Co., Ltd

Via Udine 103 K1-5-301 Hi-Tech Green Industrial Base, No. 6 of Rd 6th 33017 Tarcento Hi-Tech Development Huayuan Industrial Park Italy Tianjin 300384 China Phone: +39 0432 799 253 Fax: +39 0432 792 058 Phone: +86 22 2378-7828 [email protected] Fax: +86 22 2378-3828 www.sms-group.com [email protected] www.ares-furnace.com W 7- 320 E · Published on 24-04-17 · Printed in Germany KD · Circulation 1.000

The information provided in this brochure contains a general description of the performance characteristics of the products concerned. The actual products may not always have these characteristics as described and, in particular, these may change as a result of further developments of the products. The provision of this information is not intended to have and will not have legal effect. An obliga- tion to deliver products having particular characteristics shall only exist if expressly agreed in the terms of the contract.