STS BLOOM CASTER FOR SPECIAL STEELS STARTED 2010 IN THE OLDEST HIGH-TECH METALLURGICAL CENTRE OF RUSSIA CELEBRATING

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1 STS BLOOM CASTER FOR SPECIAL STEELS STARTED 2010 IN THE OLDEST HIGH-TECH METALLURGICAL CENTRE OF RUSSIA CELEBRATING 250 th YEAR OF PRODUCTION OF TOP LEVEL STEEL QUALITY Giorgio CABAI president STS Fabrizio CABAI managing director STS Matteo BELLINA technical manager STS IZHSTAL celebrated its 250 year anniversary in 2010 and STS had the honor to supply & successfully commission the Continuous Casting Machine tailored to their peculiar melting shop layout and designed to meet the highest quality demand of blooms, mini-slabs and billets. STS is proud to have been an active part of this celebration where quality and pioneering leading high technology was the philosophy of this company. In fact IZHSTAL is since so many years the Steel Metallurgical Centre with no stop research and achievement, even the famous Mr. Nobel was a manager in this plant and Mr. Putin himself witness the STS caster start-up, confirming the high strategic value of this plant. Mr. Putin at plant cast ceremony (source: from Russian TV)

2 The unique technological processes have been implemented over the years with quality results that would surprise any visitor of their marvelous private Museum where processes are so well reproduced. STS got the order for the CASTER on turn-key basis including initial consumables, with performance guarantees, based on a thick book of strict standards covering more than 150 steel grades covering of most extreme and wide industrial applications. IZSHTAL highly qualified and experienced managers and staff has been extremely cooperative in all phases of the project but at the same time very demanding for their quality targets exceeding the world standards. Finally after long and comprehensive testing on a wide range of products fulfilling the performance guarantees, STS obtained from JSC MANAGEMENT COMPANY MECHEL that owns this plant, the acceptance certificate and a letter of compliments. In line with STS conservative philosophy, we have decided to release news on this plant only after full good plant production and performance and in full agreement with the owners. The caster with three strands, is designed to serve the two E.A. Furnaces and LF respectively with 30t and 42t maximum capacity, to produce sizes of sections ranging from #100x100mm to #180x180mm and cutting lengths ranging from 4m to 12m. The main characteristics of the plant equipment supplied can be summarized as follows: MAIN TECHNICAL FEATURES Machine Radius 7m Number of Strands Three (3) Steel Grades Ladle Capacity Sequencing Facility Weighing Management Tundish type Tundish Car Casting Equipment Mould Type Speed Control Low, medium and high carbon steels, stainless, medium and high alloyed Maximum 42t with sliding gate system and porous plugs Ladle car for two ladles with hydraulic lifting system Tundish and Ladle monitoring by load cells 10t capacity operating with protected or open stream, controlled by stopper rods or nozzle changers Fully cantilevered, equipped with hydraulic lifting system #125x125mm and #140x180mm Curved, tubular, multi tapered 1.000mm long with electromagnetic stirrer With minimum radioactive emission and automatic start

3 Mould Lubrication Mould Oscillator By alternative proportioning pump with variable flow and automatic powder delivery system Hydraulically controlled with adjustable stroke and frequency Guiding Apron In line electromagnetic stirrers, pneumatically pressurized guiding rolls with progressive force according to billet size and casting speed, optical billet temperature monitoring Withdrawal Straightener Dummy Bar System Cutting System Scarf Removal Cutting length Billet Identification Billet Transfer Billet Discharge Cooling System Pollution Control Auxiliary Equipment Plant Supervision HMI level 2 Double radius 7/13m, two withdrawal powered rolls, computer pneumatic pressure control during casting according to cast size and speed or re-stranding function Solid type with overhead tilting/parking, pneumatically controlled By automatic innovative oxygen / gas, cutting torch suitable also for stainless steel, having high speed cutting capability with long flame powerful cutting tip for minimum metal loss and perfect cutting surface creating minimum scarf Automatic blade type system Adjustable from minimum 4m to 12m with very strict tolerances of few millimetres Unique STS impact type computer controlled marking machine installed on transfer roller table with combine b billet weighing, marking 12 personalized characters each billet Single rollers for all strands Overhead bridge picking up each billet, lifting by approximately 2m and transferring on first notch of cooling bed, same bridge can feed hot billet transfer or short billet sorting Hydraulic turnover walking beam cooling bed with grouping of billets for easy removal and storing by overhead crane (machine already designed for future application of billet slow cooling system for special steels treatment) The machine is equipped with fume extraction also in the torch area Controlled cooling furnaces designed for a wide range of qualities

4 Erection of the caster has been executed focusing on the utmost precision and care required by the strategic and high quality production of this plant. Record installation time was not a point of discussion on a plant so fully accessorized and with a so high target of quality and production level. In fact from the first meetings was clear and agreed that the important point was to have the best available technologies installed, for a casting plant that must be a reference for the biggest Russian steel company on his historical and most important production site. Thus the caster, as can be deducted by the preliminary data reported above, had been equipped and completed in the better way with accessories for high quality production, with the most advanced automation and controls for the process on line monitoring, for precise and sure bloom managing system with bloom weighting, sorting, marking and with controls and supervision for operators help and for monitoring of machine operation and status. We report here below some details on the most advanced and peculiar characteristics of this machine. MACHINE DETAILS In details and specifically for bloom quality the following special cares and equipment have been applied on the caster to fulfill the requests, just to mention the most important technical solutions of a caster that was considered for STS as special from any point of view: 1. Mould powder automatically controlled powder addition system The system is independent for each strand and is installed on top part of tundish cars as per below sketch.

5 The system is composed by dedicated silos with capacity sufficient for a complete sequence, the silo is equipped with heating system to assure moisture free powder to be fed into the mould, with level controls and at silo base a suitable dosing system pneumatically actuated delivers the right amount of powder according to casting condition in a completely automatic way. Suitable duct flushed with Argon convey and distribute the powder on the meniscus. With this system the operators are only monitoring the situation on the meniscus, being able with 1 operator to monitor more than 1 strand in more safe and with more consistency and reliability of the process. 2. Argon feeding controls for tundish to mould area The system is composed by a dedicated Argon box installed on the tundish and equipped with flow controls to deliver the right amount of purging gas to the connection between tundish nozzle and submerged shroud. The system allows fulfilling the requested guaranteed values over gas pick up in the final product.

6 3. Multi taper copper tubes with profiles selected specifically for the condition of the Izhstal plant The copper tube design was very critical due to the wide variety of steel grades to be cast and so to the wide range of casting speed values, the best solution has been found with complex multi taper design in several steps to assure proper contact for all the grades to be cast, with first priority at most critical ones. 4. Automatic mould level control with fast start-up The STS in house developed control system has been utilized for fast response even with low power radioactive source; this system allows full control by STS of all working parameters for a fast set up and immediate performance just after start-up. The capability of the STS mould level control system was of prime importance in Izhstal plant mainly for the requests on bloom surface quality that requires an absolutely stable level in every condition.

7 The precise and easily adjustable response of the STS controller allow also the Customers to work even with old radioactive sources that with other systems must be changed earlier for decay with time spending procedures. 5. Mould electromagnetic stirrer with external coils for the quickest cast size change and better flexibility of the machine and strand stirrer with adjustable position to be moved according to cast size and casting condition in the best possible way to comply with the solidification and metallurgical requirement of ALL the steel grades to be cast and produced in TOP quality Due to stringent requests of bloom internal quality and segregation a couple of stirrers have been considered in all strands: the upper one giving the best improvement on surface and primary solidification structure, and the second one along the curve giving his contribution to the internal quality soundness and eliminating segregation.

8 In consideration of the quite different size of the cast product and the wide range of steel grades the strand stirrer in the apron has been designed to be moved along the radius be positioned at correct solidification point in any casting condition and precisely for the segregation-critical steels. 6. Completely automatic cooling water management for both primary and secondary cooling, with dedicated nozzles on secondary cooling cages and bloom continuous temperature monitoring for all strands at cooling chamber exit The system is adjusted in a completely automatic mode via control valves and suitable sensors following the specific casting condition and steel grade according to specific recipes inserted in the system. Additional feedback of bloom temperature measured at the exit of the cooling chamber is also giving control for double checking that the process is running as per set and requested metallurgical condition. 7. Cutting torches with powder addition system for stainless steel fast and precise cutting in any condition and with fume suction system For the blooms cutting the torches were chosen for the absolute need of avoiding the deformation created by the shears, and the special high alloyed steels to be produced in Izhstal requires the iron powder addition, so this system has been integrated in STS designed high speed simple and reliable cutting torches creating a dedicated machines set, that has been equipped also with fume suction system due to the local stringent rules also for safety and health in the working environment.

9 The torches has been tested during performance period on all steel grades cutting with reliability and safety all products. 8. Bloom de-burring system The absolute care of Izhstal for product quality and the need of eliminating time consuming procedures of bloom conditioning STS was asked also to install device to clean the little burr created on the lower face of the blooms by torch cutting. We ve done this in line with our common view of the machinery, that need to be simple sturdy and reliable, and we ve created a simple knife device pneumatically actuated that hits the blooms under face cleaning it very efficiently. On the following picture the appearance of 140x180 mm bloom ends as per STS cut and de-burring process. 9. Bloom slow cooling system The wide variety of steel grades produced, comprising steels for bearings, steels for tools and for springs had suggested to have in the CCM provision for future installation of bloom slow cooling system. This was required from metallurgical point of view to assure quality of the hard steel grades preventing in these qualities cooling cracks and assuring proper structure for further processing.

10 The slow cooling system has been fully engineered from STS with a dedicated couple of beds totally insulated and covered, designed for 10 and 12 m bloom lengths. The bloom handling system in the caster has been already made suitable for discharging the blooms on dedicated roller tables for immediate transfer to the slow cooling beds. The system installation has then been postponed for organization reasons. On the other side specifically for bloom control and management the following special cares and equipment have been applied on the caster to fulfill the requests: 1. Bloom weighting system on transfer roller table The wide variety of steels produced and the need of optimize the length and weights for production control and further rolling optimization asked for on line weighting of the blooms. The weighting system is installed on the transfer roller table and is served by a lifter that lifts up the bloom from the roller table and sits it on load cells.

11 the weight is registered on the production tracking system for each bloom produced and can be recovered from the historical data base. Bloom laid down on the roller table just after weighting and punch marking is visible in the following picture. The system is installed just in front of the marking machines, so that just after weighting the blooms are punch marked on the head and then proceeds to the de-burring, cooling and discharging system. 2. Bloom marking system on transfer roller table With the aim of avoiding costly controls and bloom mixing the caster was equipped with marking machines. The marking machines are completely automatic and are punching o the heads of the blooms suitable code, decided and modifiable by the Customer recording furnace used to produce the liquid-heat number-billet number- strand. The codes are defined automatically by the control system during proceeding of the production and are punched and recorder in bloom SW historical data and quality control system for any further analysis. The appearance of head punch is shown in the following picture.

12 3. Bloom discharge system with possibility of selecting short blooms and to discharge to roller table dedicated to hot charging or bloom controlled slow cooling The design of the discharge system has been made to allow billets and blooms to be discharged to the cooling bed or to a roller table for immediate transportation and storage to a pit for slow cooling dedicated for the crack prone high carbon and high alloyed steels. On opposite side of the cooling bed a suitable frame has been designed to receive the short billets or any billet not fitting the severe quality standards in force. 4. Bloom automatic SW for quality control and tracking system The full set of information available by all sensors and controls on the machinery are used to provide on line monitoring of the process via software as already available on all up to date casters. In Izhstal all production parameters together with all surveyed parameters are thus recorded from the field sensors and collected on the fly for every 10 mm slices of bloom/billet to provide an historical record of data suitable for easy classification of all materials produced (casting speed, temperatures, water flows, bloom temperature, withdrawal pressures, cutting data, bloom weights, marked codes etc.). Examples of Billet Tracking system pages from which the data are manageable are reported here below.

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14 MACHINE TEST PHASE AND PERFORMANCES During erection the base mechanical equipment has been installed with perfect alignment and leveling that was a must in this peculiar situation, moreover the additional equipment mentioned above had requested additional effort during installation and setting up. In the same period and before plant start-up a proper and full training with lessons have been done covering the continuous casting theory, the machinery mechanical details and the automation and controls, this to allow all operators to operate, manage and maintain the machinery in the better way. Even if only the specific details of the new machinery really needed some clarification; since the metallurgical heritage of the plant operators and the full passion of all people involved had really helped the preliminary and start-up phases of the plant. Theoretical training has been then completed by practical operation on the caster during cold testing period and during first hot testing, always done in full cooperation between STS personnel and Izhstal operators. After erection the machine cold testing procedure has been agreed and executed between STS and Izhstal as per detailed protocol issued together and in full collaboration.

15 All measures, parameters, data sets, and details have been considered, verified and tested to safely start production in the better way with the shortest possible learning curve. With these premises the plant start-up took really limited amount of time, and after the first cast with the presence of Mr. Putin the plant go on casting and passing satisfactorily the preliminary phases of hot start-up. Then the performance tests have been started according to contractual statements and with sequence and procedure agreed between the parties. For casting purposes the steel grades to be produced have been divided in groups/families having similar behavior, so that the casting parameters can be defined for the families grouping similar steels. In this way the caster set up is easier and must be changed less frequently, the so called recipes have been defined for all families in a comprehensive technological manual submitted to the Customer in due time before the testing. The wide range of steels to be produced did a little complicate this preliminary phase of work and the number of families for Izhstal come out to be not so small, as per details reported in the following table. Steel GROUP Type of Steel Specific Steel grades in Izhstal Production Program 1 Peritectic Steel 1a: 20Г, Св-08, Св-08ГА, Св- 08ГС, Св-08Г2С, Св-08А, Св- 08АА, Св-08ХГ2С, Св-10ГА, Св-10Г2, Св-12ГС, Св-08ХМ, 10, 15, 20, А11, А20, 09Г2С Production 125x125 [t] Production 140x180 [t] Medium Carbon Steel 3 HIGH carbon Steel 1b: 12ХН, 12ХН2, 12ХН2А, 12ХН3А, 12Х2Н4А, 20ХН, 20ХН3А, 20Х2Н4А, 15Г, Св- 06НЗ 30ХН3А,40ХН, 45ХН,50ХН, 15ХГН2ТА, 19ХГН, 20ХГНМ, 40ХГНМ, 20ХН2М, 40ХН2МА, 25Г,35Г, 40Г,45Г, 50Г, 30Г2, 35Г2, 40Г2, 45Г2, 50Г2, 25Г2С, 25, 30, 35, 40, 45, 50, А12, А35, АС35Г2, А40Г, АС40, 17ГС, 20ГС 65, 70, 75, 80, 85, 65Г, 70Г, С62D2-C98D2, 50Р, 55, 60, У7А, У8А, У8ГА

16 Steel Type of Steel GROUP 4 4a: Steel Alloyed with Cr/Cr-Si/Cr-Si- V/Cr-B-Mn 4b: Steel Alloyed with Cr+Si+Ni 5 Steel Alloyed with Cr-Mo /Cr-Mo-Ni-V-Ti 6 Steel for Bearings/ Tools 7 Spring and structutal steel with Cr-Si 8 Stainless steel and Cr-Ni steel of high treatment Specific Steel grades in Izhstal Production Program 18ХГ, 18ХГТ,, 25ХГТ, 25ХГМ, 15ХМ, 20ХМ, 30ХМ, 30ХМА, 35ХМ, 38ХМ, 38ХМА, 40ХМФА, 25ХГСА, 30ХГС, 30ХГСА, 30ХГСН2А, 35ХГСА, 15Х, 15ХА, 20Х, 30Х, 30ХРА, 35Х, 35ХА, 38ХА, 40Х, 45Х, 50Х, 50ХГ, 20ХГР, 7Х3-9Х1, 15Г, 35Г, 50Г, 10Г2, 40Г2, 17Г- 17ХГ, 35ГС, 20ХГСА 20ХНР, 20ХГНР, 20ХГНТР 15ХФ, 40ХФА, 47ГТ, C3D2-C60D2, АС38ХГМ, АЦ20ХГНМ ШХ15, ШХ15СГ, ШХ20СГ, У9А, У10А, У11А, У12А, У13А 33ХС, 38ХС, 40ХС, 55С2, 55С2А, 60С2, 60С2А, 60С2Г, 65С2ВА, 70С3А АЦ20ХН, 08Х13, 20Х13, 12Х18Н10Т Production 125x125 [t] Production 140x180 [t] For each one of the above groups specific information have been listed in the Operation & Technological Manual for machine setting-up, casting parameters, and operations details. The set of information and process data comprises synthetically the following: tundish preparation procedures tunsish pre-heating cycle& final temperature tundish nozzle characteristics covering powder type and adding procedure mould lubricant (oil or powder) and addition procedure/quantity Argon flushing procedure and set data mould level set point and regulation

17 primary cooling water characteristics and set points M-EMS set point data oscillation frequency and stroke data secondary cooling nozzle set-up secondary cooling water characteristics and set points F-EMS position and set point data bloom exit temperature data casting speed data cutting torch pressures set points cutting torches iron powder set points bloom cut length data bloom marking code bloom weight set point Some of the data are of course automatically set from the caster control system just by selecting the steel grade and cast size on the recipes page on HMI. The operators were in any case free to modify-enter-adjust the set point parameters on the STS user friendly and very intuitive MHI interface. And some adjustments were easily made during first testing from Izhstal operators or STS with the aim of optimizing the bloom quality through fine tuning of set points & parameters for the specific operative situation faced during performances testing. The requests of quality were in fact so tight that every aspect of operation and process was analyzed, tested and finally set for the best result. A short summary of the guaranteed parameters that have been considered during testing phase is reported here below.

18 General Parameters Type of Parameter GUARANTEED PARAMETERS Number of heats and sections Section sizes and steel grades Casting Speed Casting yield Productivity tests Notes definition of requested number of heats for each cast size for performance tests definition of the specific steel grades to be used for performance tests as selected from each group Dimensional Tolerances Figures SIZE OF CROSS SECTION FACE BULGING / DEPRESSION RHOMBOIDITY (square sections) BILLET LENGTH BILLET STRAIGHTENESS BILLET TWIST Surface Quality Requests MACROSTRUCTURE AXIAL (CENTRE) POROSITY CENTRE CARBON SEGREGATION EQUIAXED ZONE LIGHT CONTOUR (WHITE BAND) INTERNAL CRACKS NITROGEN PICK UP Casting Machine Tests Re-stranding time Tundish life and sequence Mould changing time Time for section change Of course all the above guaranteed parameters had to be tested and verified for both cast sizes and for select specific steel for each steel group. The steel grades finally selected for testing are reported here below, and are covering practically each family of steel today in production, represented by the most critical specific variants.

19 Steel Group 2 4a 7 6 4b Steel Type Medium Carbon Steel Alloyed with Cr Ni and Ti Alloyed Steel Alloyed with Cr Mo V and Ti Spring Steel Alloyed with C and Si Steel for Bearings Alloyed with high Cr Alloyed Steel Alloyed with Cr Ni and Ti Specific Steel Grade for Test Heats Number of Test Heats 15ХГН2ТА 2 18ХГТ 2 60С2 2 ШХ15СГ 2 20ХГНТР 2 1a Peritectic Steel Св08 2 1a Peritectic Steel 09Г2С Free Cutting Steel Alloyed with hhigh S Austenitic Stainless Steel АЦ20ХН 2 12Х18Н9 2 Billet/Bloom Section [mm] 125х х х х х х х х х х х х х х х х х Casting Mode Open & Protected stream Protected stream Protected stream Protected stream Protected stream Protected stream Protected stream Protected stream Protected stream And even if the stainless steel was not initially introduced in the steel grades selected for testing we finally agreed to insert al this for completeness and full satisfaction of both parties in machine testing. So the testing period last some months, ad during that period more than 500 heats have been cast. The surface quality of the billet was immediately good and only small internal cracks on some of the more critical grades required some tuning. Finally all requested figures were met with complete satisfaction. Typical cross sections of some representative sample blooms are reported here below for information.

20 Rectangular Bloom 140x180mm Peritectic Steel Св08 Rectangular Bloom 140x180mm Alloyed Steel Alloyed with Cr Ni and Ti 20ХГНТР

21 CONCLUSIONS The strategic new caster in Izhstal was a challenge for the Mechel group, investing in one of their most important and historical sites, pushing forward for progress aiming to very important targets for both production and quality. The wide range of steel grades to be produced and the high quality targets could had been out of any doubt the best test bench for everybody in this field. And the challenge was picked up from STS with respect in front of such a big group and stringent performances requests, but also with the strength and the determination of a small company full of passion. STS knows that his standard continuous casting machine, as developed internally since years, simple, sturdy and maintenance free, could meet the highly demanding requests of Izhstal. STS knows also that the flexibility of design of this machine gives the possibility to accessorize and complete the machinery for the most critical and stringent production and quality requests. The so completed casting plant, fully accessorized on demand for this specific project, was thus installed and started up successfully thanks also to the help of prepared personnel of Izhstal. The hot phase and the performance tests took reasonable time to cover the wide range of steel and casting conditions, and finally all the requests were fulfilled for the complete satisfaction of the Customer. This caster is the practical success and example how the long tradition of STS machinery designed to reduce maintenance and increase reliability can be equipped, even step by step, with the most advanced features to meet the most critical quality requirements.