Bangladesh steel re rolling mill (bsrm)

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Bangladesh Steel Re-Rolling Mill (BSRM)Bangladesh Steel Re-Rolling Mill(BSRM)HASAN SHAHRIAR SAJIBStudying B.Sc. Engineering Mechanical EngineeringBangladesh University of Engineering & Technology (BUET)1STEEL SECTOR IN BANGLADESHBangladesh has more than 400 steel millsTotal production capacity 80 lakh tonsCountry demand 40 lakh tonsSteel consumption 25 kg/capitaLeading steel companies: BSRM, KSRM, AKS, RSRM, GPH, PHP etc.BSRM and AKS provide 50% of country demand2INDUSTRY OVERVIEW: BSRMFirst fully automated Re-rolling mill in BangladeshOperated since 1952Was sister concern of Meghna Engineering Works LtdBSRM Steels Ltd. Started operation since April 1,2008Initial production 3.75 lakh tons per yearAt present production is about 7 lakh tons per yearIndustry was fully conceptualized by Forni Industriali Bendotti (Italy) and Denieli group (Belgium)3INDUSTRY OVERVIEW: BSRMMain product in Xtreme 500w, also produces 400w, 300w, 200w, 60 grade, 40 grade1984 Introduced high strength cold-twisted steel bars to the construction industry.1987 Introduced ASTM 615 grade 60 reinforced steel bars.1996 Commissioned the largest billet making plant in the country.2006 Introduced micro reinforcement wires for low cost rural construction.2008 Introduced grade 500 steel bars, the current international standard for modern construction-BSRM Xtreme 500 W. 2008 BSRM group contributed nearly tk.100 crores to the national exchequer in taxes, levies, duties and vat.2009 The largest billet making plant of the country nears completion4THE ADMINISTRATIVE INFRASTRUCTURE OFBSRM STEELS LIMITEDThe entire work schedule of the industry is divided into 11 departments. They are:AccountsAdminHR and IR (Human Resources and Industrial Relationship)InventoryCSD (Customer Service and Development)Production DepartmentworkshopElectricalMechanicalQA (Quality Assurance) andT&D (Technical and Development5ORGANOGRAM6WATER TREATMENT PLANT (WTP)WTP supplies required water in the mill, and treats the used water for re-circulationTwo types of water used- Contact (used in mill)Non-contact water ( used in QTB and heat exchanger)Total pumps: 31Total filter: 53 sand filters (used for filtering Contact water) 2 anthracite filters (used foe removing iron particles)7WTP OVERVIEW8WATER TREATMENT PLANT (WTP)Water filtration process: 3ManualChemicalFiltering Backwash method is done in every 8 hours for removing scale from filterChemical used : NaOCl, anti corrosive chemical, coagulants, dispersants etc.Cooling tower: total 7, forced induced draftsReduces temperature almost 8 degree CelsiusTotal capacity : 3000 m3/hr.9FURNACEFurnace type: Pusher Billet type Re-heating FurnaceDimension: Length: 22m Width - 15m Height - 7mBurner number: Total 22 10 in heating zone, 12 in soaking zoneAir-Fuel ratio: 10:1Fuel used: Duel fuel:Natural GasLight Diesel Oil (LDO)Pressure: 0.3 barTemperature: 1200 degree Celsius10FURNACE3 zones:Pre-heating zone (billets are heated by pre-heated air up to 400 C)Heating zone (billets are further heated up to 1200 C)Soaking zone ( maintains the temperature gained in heating zone)Peel bar :Used to push the billet out of furnaceBillet detector ;2 billet detectors are used for positioning the billets inside the furnaceRecuperator:Used to pre heat air 11MILL AREA Heated billet goes through a shape changing process by rollingTwo types of rolling stand:Vertical: 8Horizontal: 12Three area:Roughing area: 8 standsIntermittent area: 6 standsFinishing area: 6 standsLooper: max. 6 (use to reduce tension of heated rod)Slitter: use to split the billet for less dia. rod12MILL AREAQTB (Quenching and Tempering Bath)Use for uniform cooling of heated rodMartensite formationDirect contact of water, rapid coolingTemperature is reduced by 200 C Shear Machine:Detach the billet in head & tail positionThree shear machineShear 1 (between stand 6&7, cuts the head portion)Shear 2 (between stand 12&13, cuts the tail portion)Shear 3 (placed after QTB, cuts the billets according the cooling bed size)13FINISHING AREAThe quenched rod after shear-3 moves through hereThe main components operating in Finishing Area are:Inclined Apron Roller Table Cooling BedCold ShearTying MachineInclined Apron Roller Table 72 motor-driven rollers: imparts motion to the discontinuous rods71 Lifting Aprons: shifts the rods lengthwise to the cooling bed5 interconnected hydraulic cylinders: controlling simultaneous opening and closing of the aprons3 Magnetic Stoppers: stops the rods moving at high velocity14FINISHING AREACooling BedTwo types of racks; Fixed and Movable: shifts the rods along transverse directionThese Movable jaws are driven by a single motor.Two gear boxes having worm gear transmits power from motor.Eccentric cylindrical cams are connected in series in the driven shafts.Cams have counterweight adjusted at 180 degree. Hydraulically driven arms transfer the rods from the cooling bed to a rolling trolleyThe rolling trolley transfers them in their longitudinal direction to Cold ShearCold Shear AC Motor Driven System Motor Flywheel Clutch-Brake SystemAxially displaced parallel shafts by cams to move the upper jaw to cut the rods.Belt pulley 15FINISHING AREALayer Chain TransferVertical Chain TransferTying MachineTying Machine:5.5mm wire is spool fedHydraulic Mechanism with Hydraulic Motor ,oil storage tank for hydraulically driven small rollers or flap.8 steps controlled either automatically or manually1. Feed wire- by hydraulic motor.2. Clamp wire- by hydraulic cylinder.3. Binding unit up- by hydraulic cylinder. 4. Stretch wire- by reversing hydraulic motor.5. Twist knot- by hydraulic motor.6. Wire clamping off- by hydraulic cylinder.7. Reset twisting head- by hydraulic motor.8. Binding unit down- by hydraulic cylinder.16OVERHEAD CRANE4 Bays12 Overhead CranesMagnetic TypeA-B Bay : 3 cranesGirder Capacity: 29 tonsLifting Capacity: 8 tonsB-C Bay: 4 cranesGirder Capacity: 24 tonsLifting Capacity: 8 tonsC-D Bay:3 cranestwo of 10 tons, one of 20 tons D-E Bay:2 cranes10 tons and 20 tons17OVERHEAD CRANETypes of Motions:Long TravelCROSS travelHoisting Travel (Lifting and lowering)Rotational TravelTelescopic motion (A-B Bay only)Lifting Mechanism:Magnetic action induced by Electric flux changeBattery backup for 20 minutes to the magnetsHoisting travel control: cable-rope system with brake pads18UTILITIESSupports the entire mill to run smoothly.Consists of :Hydraulic drive systemPneumatic drive systemLubrication systemGreasing systemHydraulic Drive System4 central hydraulic unitFurnace central hydraulic unitUsed in driving pusher & peel bar.Milling central hydraulic unitUsed in driving pinch roll, chain transfer system, hood(up-down movement)Finishing area central hydraulic unitUsed in movement of QTB, apron lifting operation, tying machine.Workshop central hydraulic unitAssembly operation of Robot, band saw up-down.19UTILITIESHydraulic system containsTankHydraulic oil( vg46 or vg68)Energy ConvertersControl DevicesAccessories (Float valve, Accumulator etc.)Connecting deviceElectrical & Electronic components20UTILITIESPneumatic drive systemApplication:Peel bar upper pinch rollPeel bar entry doorFurnace exit upper pinch rollBillet DetectorLooper roller up-downPneumatic system containsCompressorDrierReceiverFRL( Filter-Pressure Regulator-Lubricator)Control ValvesActuators21UTILITIESLubrication Force lubrication is used in this industryHas 3 unitsRoughing Stand Lubrication UnitIntermediate Mill Lubrication UnitFinishing Stand Lubrication UnitLubrication system containsReservoirPumpHeat Exchanger( Remove moisture content)Filter( Remove metal & dirt particles)Lubrication oil(vg 220) 22UTILITIESGreasing systemGrease generally consists of a soap emulsified with vegetable oil.A central grease unit is present to pump grease into required places keeping the time gap to 30 minutes.Has 3 greasing unitsRolling Mill Central greasing unitFinishing Area greasing unitShear 1 greasing unitCold shear central greasing unit23BENDING MACHINEBending machine is used to bend 12 m rods into 6 m rods for carrying in trucks Driven by electric motoring4 rollers to bend the rods smoothly.A rotating jaw bend the rods.A movable arm driven by pneumatic power helps to slide the rods into delivery chain transfer9 men are required to work on a Binding machine3 for counting3 for tying3 for delivery 24QUALITY ASSURANCE (QA)Main Purpose is to ensure the product quality.BSRM always try to improve product quality with best techniques of the world.They ensure ISO 9001:2000One set of rebar is checked in every hour. For 500WYield strength is 500MPa. Ratio of tensile and ultimate strength is not more than 1.15Testing Instruments:Bar bending mandrelCNC roll turning latheUniversal testing machineComputer attached with UTMSpectrometer Microscope 25REBARThree layers Martensitic caseTransition zoneFerrite-Pearlite coreMartensitic case provides hardness of steel.Ferrite-Pearlite core provides ductility of steel.Controlling the amount of water flow of QTB, we can control the marten site layer thickness.Martensitic layer should not be more than 40% of total rebar x-section area. 26WORKSHOP The workshop of BSRM is very much enriched. The performance of the workshop machines makes the industry self- dependent. Excelled engineers and technicians maintain the workshop.The work shop instruments:Shear MachineCNC-Roller notching MachineCNC-Lathe MachineManual Lathe MachineBench Drill MachineRadial Drilling MachineSurface Grinding MachineRobot27WORKSHOP FACILITIES Dressing of gear teethSurface grinding operationRepairing mechanical equipmentInterchanging between horizontal and vertical standsBSRM does all kind of repairing and maintaining works in their workshop. This saves a large amount of money of the industry and enhances the profit.28THANK YOU ALL29


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