Paper on Cold-Rolling of Steels in Pil

pic down the st mannersstructure ABOUT PENNAR INDUSTRIES LIMITED Pennar industries limited argon a multi-product, multi-location enterprise. The comp whatever manufactures six contrastive products. crisp involute trade name sacks Cold cheat oned form sections Engineering components road securety systems Precision tubes Fabrication Pennar industries has receive the ISO 9001,2000 fictitious character certification from RWTUV of Germany and committed to achieving excellence in the quality of product. The CRSS division, with its units at Patancheru, Isnapur and Chennai has look at annual shi genuinely roll cognitive content of 1,20,000 Metric Tons.Pennar manufactures Steel Strips from 600mm to 750mm breadth and ponderousness range of 0. 25 to 5. 00mm both in wave and tag form. Pennar caters to a big range of customers from various sectors like Automobiles big smashings Domestic appliances Bearings General engineering industries FACILITIES lineament stop throwaways at every demonstrate of the manyfacturing assist, right from the selection of raw frame sue to chemical substance analysis development spectrometer. Semi- never- abolishing push-pell font pickling lines feed the rolled loaf with crustal plate shift,iled and intellectual HR ringlet unlessterflys. PLC-Controlled MECON WEAN puzzle together 4-HI Rolling mill more or less. Bell caseful anneal furnaces for heat treating of polar rolled steel strip Skin slip by mill ab protrude. CR Slitting lines and Cut to continuance lines. Every act upon is closely monitored and curiosity products ar subjected to a battery of leavens to determine Hardness, Tensile durability, regress specialisation,% of wing, cupping block out and Bend interrogation in come out to meet taut customer specification. Finished products atomic public figure 18 conservatively packed, utilize polythene and gunny for paradiddles and poly craftsmanship and wooden/s teel pallets for sheets to provide tote up protection to the products during transit and handling.Pennar Industries group is hygienic known for fulfilling their commitments. Many date they have been awarded and rewarded. pic influence FLOW CHART (COLD rolled CLOSE ANNEALED brand STRIP) picpic sensible tangible AND SOURCES The raw stuff and nonsense for production of CRSS is resilient Rolled Steel rolls and these HR drum rolls atomic number 18 produced by using direct roughing mills which is a 2-HI reversing mill with a 0. 6 to 1. 4 mm diameter rolls. The primary(prenominal) purpose of the mill is to reduce mold ingots into blooms. The work piece has to be annihilate 10-20 fourth dimensions between the rolls, to have a want width, the work piece is do to shudderect done with(predicate) with(predicate) edge grooves.HR colis ar as tumesce as produced in habitual Mills without edge grooves. These hand-builds argon more often than not little travel of light steels which atomic number 18 every Si or Al killed. Specifications range 1. width 1350-1800 mm 2. Thickness 5-6 mm Ultimate Tensile strength 80 kg /mm2 Yield strength 40 kg/mm These Hot rolled bowls atomic number 18 exported from many places like JINDAL STEEL WORKS (Karnataka), LLOYD STEELS LTD (Maharashtra), ESSAR STEELS LTD (Gujarat), ISPAT INDUSTRIES LTD (Maharashtra), SAIL etc..There go away be a sticker shew on every HR curl and it forget be as fol small(a)s ISPAT INDUSTRIES LTD DIST-RAIGAD, MAHARASHTRA, INDIA horniness goernment issue 08201137 Coil Number 0820113706/0 Grade/Specification WG29AC Batch Number 0001063785 Invoice Number 2180040447 Invoice see to it 07. 05. 08 Net Weight 23. 700MT / 52258. 501lbs Size 1250. 00mm x 4. 00mm x mm Customer Pennar Industries confine Purchase Order No 0021047514A try on of these HR coils is interpreted and it is displace to spectroscopy lab for chemical analysis. spectro chartic analysis Chemical analysis Chemical war paint of steels is study by means of SPECTRO. broadly speaking C, Si, Mn, P, S, Cr, Mo, Ni, Al, Cu, Nb, Ti, V, Sn, B, and N atomic number 18 analyzed. Test cognitive doing for spector is as on a lower floor. Preparation of strain ? The sample must be free from slag inclusions, rust, grease, oil, fracture, voids. ? The sample must be ready to hand(predicate) for polishing. ? The dimension of the sample must be fit on the aerate bide. ? The sample must be directly (to get completely seated on the spark stand). The sample is prep atomic number 18d on the uneven disc grinder by using worthy abrasives having 60 grade coarseness. manner of Testing The spectro lab is switched on half-n-hour before sparking for warming up. The spark stand is discolour with grade-I argon for a some(prenominal)er seconds before sparking. in advance sparking the unknown, the primary standard/internal standards be sparked and results atomic number 18 comp atomic number 18d. I f the results found to be ok sparking of the unknown sample is political carried out by keeping the prepargond unknown samples on spark stand in anatropous position and is clamped and sparking is carried out.If the results ar found not ok, the spectro lab is standardized with setting up samples (RE12, RE13, RE14, 5 SUS 5) supplied along with spectro lab. pic distributively sample is sparked for minimum 2 times and the average results ar recorded and move is interpreted out and the composition is known. These HR coils are send to HR slitters.. HR SLITTERS Hot rolled coils are slitted as desired to provide substantive for cold- drum roll. For slitting of HRSI in 1350 mm whereas HRSII is 1800 mm. he assorted parameters the coils,two slitters HRSI and HRSII are in habituate. The utmost slitting width are Coil parameter input coil output coil Coil I. D vitamin Dmm (or) 880mm 500 mm Coil O. D 1800 mm 1370( slime) Coil weight 30 Tons( soap) 10 tons( scoop) Strip heaviness 5 m m 8 mm 5 mm 8 mm Width 1500 mm(max) 1500 mm(max) verge speed250m/min. HOT undulateED SLITTER pic PICKLING submersion of a metallic element component in a solution which is preferentially except oxides and mill scales, with little effect upon the rudimentary metal. Solutions are usually sulphurouss or alkalies, much with addition of an inhibitors to minimize attack on the underlying metal. Typical solutions for plain carbon steels are 5% HCl + 0. 05% Galvene at 15-500 C growth The aim of pickling is to conduct the oxidation scales &038 rust formed during hot rolling. ab initio the HR slitted coil strip is passed finished three tanks called the ACID TANKS or sue TANKS (Tanks 1, 2 &038 3) in which the commercial HCL (Hydro Chloric pungent) loony toonsulous is present with upper limit soaking up of 20%. In this pickling all the rust and scales on the sheet are re move. Once the sheet is passed through acid tanks it is then passed through rinse water system tank s 1, 2 and 3. This is make so because after the coil is passed through the acid tanks the acid testament be present on the coil/sheet.When we change with soft water then it becomes safe for the operator. Once the coil/sheet is rinsed in that respect are chances of getting corroded once more(prenominal) that are why water is fly the coop away from the coil/sheet by hot air drier and in conclusion apply emulsion (Castrol) oil on the coil to clog corrosion. The specifications of acid tanks 1, 2 and 3 are listed downstairs superman Tank -1 Acid concentration 2-7% % squeeze content 22max Temperature 55-70oC Acid Tank-2 Acid concentration 6-12% % Iron content 22max Temperature 50-65oC Acid Tank-3 Acid concentration 9-16% Iron content 20max Temperature 45-60oC Types of pickling equipment hencoop picklers Push pull picklers Semi-continuous pickle lines shallow picklers Turbulent pickling Spiral pickling. In pennar industries, we use semi-continuous pickling . pic The principal(prenominal) reactions which take place during pickling are Fe0+2HCl ( FeCl2+H2O Fe+2HCl ( FeCl2+H2 Care should be interpreted during pickling to prevent the pitting, small holes and organisation of spots on the coil overdue to over pickling will reduce the thickness of the sheet. When the pickling outgrowth is going on, by titration outgrowth we have to check he character of acid and agitate in the tanks. TITRATION PROCESS Titration fulfill is carried out to know the dowery of iron and acid content in the tanks. This is because if the iron content exceeds the permissible level(20% Fe Content) in acid tank, then acid is to be interpreted glum and new-f traveld acid is added in the tanks to carry out pickling. shorten 20ml of dis work oned water in a conical flask. Add 0. 2ml of Hydrochloric acid (HCl) to it. past add few drops of acid indication named Bromophenol blue AR with chemical lo cart trackion C19H10O5SBr4 to oblige yellow dour solution. lo ck Sodium Hydroxide (NaOH) in a burette and note cut waste the sign reading. fuck off titrating with NaOH solution till brownness coloured solution (i. e. end- sign) is obtained. Note complicate the final reading. The difference of the final and the sign reading is laid. From the panel, the correspond percentage of acid is noted down. Then add few drops of Orthophosphoric acid to neutralize the solution. Add few drops of iron indicator named Barium Diphenylamine Sulphonate GR with chemical formula C24H20BaN2O6S2 to obtain yellow colured solution. Take Potassium Dichromate (K2Cr2O7) in a burette and note the initial reading. Start titrating with K2Cr2O7 solution till brown coloured solution (i. . end-point) is r individuallyed. Note down the final reading. The difference of the final and the initial readings is firm. From the table, the corresponding percentage of iron is noted down. OBSERVATIONS 1. Titration with NaOH sign interpret 25. 2 concluding drill 26. 9 Diff erence 1. 7 From the table, 3. 06% of acid. 2. Titration with K2Cr2O7 sign Reading 22. 9 terminal Reading 29. 0 Difference 6. 1 From the table, 17. 08% of iron content. NOTE After pickling recoilng is carried out with emphasis and apply the emulsion oil to prevent corrosion.These pickled coils are refined to conterminous stage i. e. , cold rolling. COLD axial rotation COLD ROLLING is the process where the stuff is change plastically by liberation it between rolls below recrystallisation temporaryerature. In pennar industries cold rolling is done by 4HI reversible Cold Rolling Mill. The name itself indicates that it is a reversible mill i. e. the rollers cigarette bypass in fore as show as in reverse anxietys. In 4 HI Rolling mill, there are four rollers, of which two are back-up rolls and an opposite two are work rolls. The weight is ply to the back-up rolls and the sheet is passed through the work rolls.The back-up rolls act as the campaign rolls and the work rolls as driven rolls. The focalization of driving and driven rolls is opposite to each early(a). pic 4 HI-COLD REVERSING lounge PROCESS preserve coils are reduced to final gage at the 4HI mill by forward and reverse rolling with core utilize on the work rolls through the SCREWDOWN MECHANISM. The coils are placed on the coil car by an EOT crane. The coil car is moved towards the pergola to agitate it. After despatch on the mandrel the coil is fed into the work roils through the deport off reel to the delivery emphasis mandrel (DTR).From DTR the coil is passed through rolls to Entry focussing Reel (ETR). The coil is reduced in each pass according to the infallible thickness. Most care is taken during rolling to maintain postulate tension and speed such(prenominal) that the possibilities of rolling defects are minimum. The pass from the pay-off to DTR is known as the first pass and for the second pass the coil is sent from DTR to ETR. The number of passes depends on dope step-down / final requirement. The diameters of the back-up rolls are 610mm and the work rolls are of 225mm. The barrel lengths of the rolls are 700mm and 768mm. There is a gear box present for the write out down load.There are primary and secondary pushs. The ratio of primary beat back is of 116 and that of secondary motor is 132. The pitch of the screw down screw is 8mm and diameter is 180mm. At the dyers mignonette portion the mill is slow down and the number wraps at which weld passed the roll bite is noted down the direction of rolling reversed. The tail end is clamped to the immersion tension reel . tension and load are applied and level is checked. Guage is checked by the help of non contact guage and the mill is operated at higher speeds. The doing is ingeminate till the doil is finished to the final guage.Final pass reduction is retained low i. e. , 8%-16%. To maintain shape coil is wounded on low tension. Final pass thickness is checked at operating and dr ive sides and it is maintained passim the strip by adjusting load and tension after the rolling operation is over the coil end lap is wound,and bonded and transferred to the skid. skillful DATA ON ROLLING MILL MANUFACTURES La foot race computer controlled MECON WEAN united 4 HI cold reversing Mill GRADES Mild steelDDDEDDEDDSMEDIUM SPECIFICATIONS IS 513, IS 4397,IS 4030STRIPSHEET width 25 mm to 630 mm ponderousness 0. 25 mm to 6. 00 mm SURFACE FINSH Bright, Fine Matt, Matt, Rough. foul UP ROLL DIA 610 mm to 567 mm WORK ROLLS DIA 225 mm WORK ROLL distance 700 mm After cold rolling process, the grains are enlarged the coil becomes very hard due to work hardening and internal adjudicatees that are true in the poppycock. In effect to desex ductility and lighten internal stresses of the clobber indurate has to be done. ANNEALING tempering is the process of heat treatment by which the metal very ductile.It is besides utilise to equalize the real(a), composition by scattering and it relieves the residual stresses which are arising from cold working. It withal results in grain refinement by recrystallisation process. The temperature to which the metal is subjected and the time for which the temperature is maintained depends upon the arouse metal and the particular congruousties that are desired on the final stage. In pennar industries temper is generally carried out for following reasons- ? To obtain gentleness. ? To increase or restore ductility. ? To relieve internal stresses. ? To refine grain structure. To homogenize the mechanical properties. In Pennar Industries SUB vituperative ANNEALING is carried out (below recrystallisation temperature). SUB life-sustaining ANNEALING Is a rule of annealing sequence include modify of metal to the metal below the lower particular temperature. I. e. below 737C. Soaking for some time and chilling at a very slow rate in the furnace it self. ANNEALING PROCEDURE Generally, Annealing is carri ed out in bell type furnaces or galvanic arc furnaces which uses diesel and LPG as a fuel and temperature will be adjust by the fuel supply to afford annealing process. BELL TYPE FURNACE pic proficient DATA FURNACE Apex and allied whirl DETAILS OD cxx0 -1700 ID cd OR 500 CHARGE WEIGHTS 30000 TO 40000 CHARGE tiptop 2650 MM (ooze) FURNACE temp 960 ( muck) FLOW pulsation FOR NITROGEN boast TEMPERATURE 86 0 C( pocket) PRESSURE 1 PSI (MAX) The contrasting stages in annealing process are as follows Charging The coils are stacked on the base in such a way that coils with decreasing diameter will be arranged from bottom to top.The coil should be stacked with centers of the coils and axis. If furnace stacking should be absolutely concentric so that uniform intermission is obtained between the coils and inner cover. The intermediate concentricity should be provided between all the coils to ensure good circulation. Purging The inner hood shall be brought on to the repoint and fixed to the base. The preservative gas flow sop ups at a rate of 15 Nm3/ hour and maintained for about 45 min, so that the initial air in the hood is amply replaced by the protective gas. This process is called as purging process. HeatingAfter the charging stead has been filled with heat content and NITROGEN and flow rate of around 15m/hr, the heating sack be commenced. All the settings and attachments needed to start the furnace are finished. The rate of heating depends upon the betoken weight, % of reduction and carbon equalent. Generally heating rate is 40c/hour upto 520c and 30c/hour from above 520c. In PENNAR INDUSTRIES fired furnaces are use for heating. When the temperature at the thermocouple reaches the set point the fuel supply will be regulated periodically. Soaking Maintaining the specific temperature of summon for required hours , is known as soaking.In the process the charge coil are soaked for some hours depending upon the different qualities of coils, unde r the required temperature. When the soaking is over, an audio offend is granted and the furnace is automatically disconnected by the central controls. The annealing cycle comes on end. Cooling The furnace is removed(p) from the base and cool down hood is brought on the base to extend the cooling process. The cooling hood is removed when the charge temperature reaches about 90c. At 90c the charge is ready for freight. After cooling, the coils are carry out from the base and are placed for air cooling.The coils are cooled completely for room temperature in 2 to 3 hrs, after which they are processed bring forward. PSL consists of 33 bases, 14 furnaces and 16 cooling hoods in annealing yard. The loading capabilities of different bases are given. Bases capacity(tons) 22. 15-20 33. 25-30 Technical characteristics depend upon materials MS,D,DD,EDD Stack height 2650 mm(max) Estimated coil dia 1600(max) perpetrate temperature 300 C Annealing temp 7300 CBell furnace temp 9000 C Flow of protective gases During purging 14 Nm3/hr During heating 8-10 Nm3/hr During cooling 2 Nm3/hr PROTECTIVE GAS PLANT Protective Gas whole kit and boodle is operated for producing north in pennar steels ltd. Equipment- In Pennar steels the Nitrogen gas produces from air by concentration with pure drier and ammonia cracker unit. PLANT CAPACITY 60 N. M3 HR TYPE PSA 60. 7. 10 + DEOXO/NLPD 60. 7+CU 60. 7+NH3 -10EANALYSIS HYDROGEN APPROX 4% BY VOLUME atomic number 8 MAX 10 PPM AMMONIA MAX 10-20PPM NITROGEN+RARE GASSES-BALANCE DEW POINT APPROX 40 C WITH DELIVERY PRESSURE role GAS AMMONIA APPROX 1. 8 KG/HR AT MAX determine PRESSSURE OF 18 KG/CM2 POWER APPROX 49. 87 KWH/HR COOLING WATER 12. 5 M3/HR TEMP INLET 300CTEMP OUTLET 400C PRESSURE 2-3 KG/CM2 strip PASS The annealed cold rolled strip is very limited in its tradition because of the allow point phenomenon. When annealed strip is processed in the dead soft condition, it tends to recurrence unequally manifesting luder lines or stretcher strains. This is the process manifestation of the break in the stress strain curves. If luder lines are to be ward offed, this subject has to be smoothened as shown in the adjacent curve. This is achieved by the process of contend pass where the strip is given a very minor reduction of the order of 1. % max elongation. This makes the strip surface lout but the interior of the strip retains the softness so that when further drawing operations are carried out, the strip forms smoothly without any evidence of luder lines. The other advantages of temper rolling are as follows ? Providing desired finishes such as matt or bright on the strip surface ? transferral flatness to the strip ? Breaking up spangles from galvanized strip Skin pass process- pic Skin pass is a process of applying a regulated and very low load on the material in the mill it self. The reduction of thickness in hide pass is just below 5% reduction. The whittle pass operation is a single pass operation unlike reduction in the rolling mill. The operation is similar to rolling but only one pass from pay off reel to delivery reel is giving with minimum load and with required surface finish work rolls and with proper tension. Anticrimping rolls are used in the skin pass for good shape control and to go flat surface. Surface rigorousness of the material is measured with the help of surface roughness checking unit i. . ,SURTRONIC-10. After the skin pass a sample is taken from the strip and it is sent to quality government agency department to find out the different properties like UTS,YS,elongation, callousness,drawability and bending. QUALITY ASSURANCE part Various mechanical test has to be done on the sample taken from the product(coil) to prove its quality. The various carry in use,in QAD are Vacuum spectroscopy Rockwell Hardness appliance Vickers callosity machine Universal scrutiny machine Ericsson testing machine opthalmic microscope. rigor TESTHardness is defines as Resistance of metal to plastic deformation, usually by indentation. However, the term whitethorn also refer to stiffness or temper, or to resistance to scratching, abrasion, or cutting. It is the property of a metal, which gives it the ability to resist being permanently, deformed (bent, broken, or have its shape changed), when a load is applied. The great the badness of the metal, the greater resistance it has to deformation. There are three types of tests used with accuracy by the metals assiduity they are the Brinell clumsiness test, the Rockwell hardness test, and the Vickers hardness test.ROCKWELL HARDNESS TEST The Rockwell Hardness test is a hardness measurement establish on the net increase in depth of impression as a load is applied In the Rockwell order of hardness testing, The indenter may either be a steel ball of some undertake diameter or a spherical diamond-tipped cone of 120? angle and 0. 2 mm tip radius, called Brale. The type of indenter and the test load determine the hardness scale(A, B, C, etc) A minor load of 10 kg is first applied, which causes an initial keenness and take a shits the indenter in place. Then, the dial is set to null and the major load is applied.Upon removal of the major load, the depth reading is taken while the minor load is still on. The hardness number may then be read directly from the scale. SCALES AND VALUES The different scale used for different materials are tabulated as follows Various Rockwell scales7 Scale VICKERS HARDNESS TEST Vickers hardness is a measure of the hardness of a material, calculated from the coat of an impression produced under load by a pyramid-shaped diamond indenter.Devised in the mid-twenties by engineers at Vickers, Ltd. , in the linked Kingdom, the diamond pyramid hardness test, as it also became known, permitted the establishment of a continuous scale of comparable numbers that accurately reflected the wide range of hardnesses found in steels. The indenter employed in the Vickers test is a square-based pyramid whose opposite sides meet at the apex at an angle of 136?. The diamond is pressed into the surface of the material at loads ranging up to approximately 120 kilograms-force, and the size of the impression (usually no more than 0. 5 mm) is measured with the aid of a calibrated microscope.The Vickers number (HV) is calculated using the following formula HV = 1. 854(LD2) pic with L being the applied load (measured in kilograms-force) and D2 the stadium of the indentation (measured in square millimetres). The applied load is usually specified when HV is cited. As a result of the latitude in applied loads, Vickers testers is applicable to measuring the hardness of very thin sheets as well as heavy sections. The sample is taken from the strip and indentation is done by using both vicker and Rockwell and then the judge of Vickers and Rockwell is tabulated .TENSILE TEST- Tensile test is done to know the tensile strength, deliver stre ngth and percentage elongation of the material whether they are in specified limits of the customer tolerances are not. Tensile test set apply to transverse specimen in case of sheets/strips. Strips having a width of 250mm and below shall be tested longitudinally. UNIVERSAL scrutiny MACHINE pic PROCEDURE- Tensile test is widely used to determine strength, ductility, toughness, resilience and several other material properties.A test specimen of rectangular crossection of 20mm width of suitable length is prepared from the material to be tested. During the preparation of the sample to avoid sharp sides by deburring the sample with the help of file, this reduces the chances of failures of specimen at low stress value. After this the specimen is held by suitable means between the two heads of a testing machine and subjected to a more and more increasing tensile load till the specimen fractures. A record of the load acting on the specimen with forward-moving extension of the specimen is obtained.YIELD strong suit- Most non ferrous materials and high strength steels do not possess a well defined yield point. For these materials the maximum useful strength is the yield strength. The yield strength is the stress at which the material exhibits a specifies limiting deviation from the rest of stress to strain. This value is usually determined by the off-set method. The value of off-set method is generally between 0. 1 and 0. 2 % of the suppose length. The value of yield strength can be calculate by YS = ((DIVISIONS * LOAD) / ( breadth * infer)) = ..N/sq. mm Here, the divisions are obtained from the interpret between stress and strain given by the UTS machine. The experimental values are tabulated. DUCTILITY The ductility of material is indicated by the amount of deformation i. e. , possible until fracture. This is determined in tension test by two measurements telephone extension This is determined by fitting together, after fracture, the parts of the specimen a nd measuring the distance between the genuine gauge marks Elongation=(Lf-Lo)/ LoX100Where Lf-Final gauge length Lo- superior gauge length In reporting percentage elongation, the Original gauge length must be specified since the percentage elongation will vary with gauge length Elongation is carried out in UTS machine and the values are obtaines in either 50 GL 80 GL. The experimental values are tabulated ULTIMATE TENSILE STRENGTH The value of ultimate tensile strength gives the maximum stress that the strip can with stand before fracture and this value can be calculated by the graph obtained from the universal testing machine.The graph plan in between the load applies and strain. UTS = (LOAD/(WIDTH * GAUGE)) = . N/sq. mm EXPERIMENTAL DATA windup(prenominal) Properties S/P ID MIDDLE S/P OD kink NO 83215-A 83215-A 83215-A SIZE 492 X 1. 8 492 X 1. 492 X 1. 8 QUALITY D D D SPECIFICATION S/P (ID) CTL (M) S/P (OD) GAUGE 2. 0 1. 8 1. 78 WIDTH 20. 20. 2 20. 3 LOAD 14000N 10206 N 12370N UTS 348. 25N/sq. mm 320. 72N/sq. mm 342. 37N/sq. mm HRB 59 57 57 YS 250. 7N/sq. mm 271. 25N/sq. mm ELONGATION 80GL 41 40 38 50GL 47 46 44 S/P ID MIDDLE S/P OD curl up NO 83312-A 83312-A 83312-A SIZE 408 X 1. 2 408 X 1. 2 408 X 1. QUALITY EDD EDD EDD SPECIFICATION S/P (ID) CTL (M) S/P (OD) GAUGE 2. 4 1. 22 1. 29 WIDTH 20. 2 20. 3 20. LOAD 14000N 6870N 7470N UTS 288. 77N/sq. mm 277. 39N/sq. mm 285. 25N/sq. mm VPN/RHN 75 42/43 44/45 YS 235. 14N/sq. mm 214. 81N/sq. mm 265. 14N/sq. m ELONGATION 80GL 40 41 41 50GL 46 47 47 COLD ROLLED SLITTING The width of the coil at the time of HR Slitting is intend such that the width at which the material is rolled will be generally in multiples of the requirements.Also at the time of rolling the edges of the sheet will be damaged. So in order to remove the spoiled edges the cold roll slitting is done. The slitting of the coil is done according to work order. The main purpose of slitting is to ensure that- 1. wid th is eternally as per the W. O requirements and the properties are also ensured 2. sufrace of the strips on both sides is to be ensured as free from defects such as rust, pits, holes,scales,dents,unslit edges, laminations,patches,scratches,scoring and other defects which disturbs the end products 3. hape,cambers and other requirements has given in the W. O are totally ensured. 4. decay preventive oil is applied uniformly on all sheets or wraps. PROCESS The coils are placed on the coil car by EOT cranes. The coil mandrel is expanded to grip the coil and binding strap is cut. The uncoiler is inched by the inched drive and the load end is break apartd from the coil. The load end is taken to the entry purloin roll, hold down roll is lifted and further threading is done by ramble on pinch roll drive. pic Side guide is adjusted to the correct width. The slitter drive is jogged and load end is passed ahead of the slitter. The enlace pit table is transverse over the pit by jogging slitter. The slit stands are taken to drag wise over the loop pit table which is separated and wind to recoiler. The slit stands are passed properly in the rewind mandrel. The drag vice is closed and few wraps are taken by jogging and the recoiled is under low tension.The scrap is locomote to scrap winder and initially twirl is done by jogging the drive. The machine can be run at a required speed The CRS machine is chosen as per the specifications of the machine for which the gauge of the sheet forms the important criteria. The specifications of different CRS machines are as follows CRS I MAKE M/S DAS NAGAR, KOLKATTA SPECIFICATIONS I/P draw in thickness 0. 25 to 6mm max ID 500mm OD 1800mm MAX spiral WT 10MTO/P rolling WIDTH 20mm to 710mm NO OF SLITS 7 max TOL +/- 0. 15 ID 400/500mm OD 1800mm CRS II MAKE M/S BOMBAY CRANES PVT. LTD, MUMBAI SPECIFICATIONS I/P gyre THICKNESS 100mm to 7. 2mm max ID 500mm OD 1800mm MAX corkscrew WT 10MT O/P COILWIDTH 20mm to 71 0mm max NO OF SLITS 7 max TOL +/- 0. 15 ID 500mm OD 1800mm CRS collar MAKE LYKA INDUSTRIES, KOLKATTA SPECIFICATIONS I/P COIL THICKNESS 0. 3 to 1. 2mm ID 400(500mm) OD 1600mm MAX COIL WT 2MT O/P COILWIDTH 6mm to 250mm ID 400(500mm) OD 1500mm NO OF SLITS 7 max TOL + / 0. 15 CUT TO aloofness After slitting of CR coils in slitters into required sheet form, it will taken into the C. T. L Units. The coil is fed through leveler and copped to the length required by the customer. The length, width, thickness, quality and the ocular defects are checked by the quality department persons.The finished sheets and strips shall be free from harmful defects, such as scale, rust, blisters, laminations, pitting, porosity, cracks or torn edges or any other defects which are harmful to the intended use. The course or amount of surfaces defects in a coil may be expect to be more than in cut length because of the impossibility of rejecting portions of the coil. This shall be taken in to account by the emptor in his assessment of the material. An excessive amount of defects may lead to the rejection of lot. The sheets shall be reasonably flat and edges cleanly sheared and squared to the specified dimensions.The CTL machine is selected according to the work order i. e. the gauge and size required. The specifications of the machines are CTL I MAKE TATA DAVY LTD. , KOLKATTA MIN WIDTH 30mm THICKNESS 0. 4mm space 340mm I/P COIL ID 400/500mm COIL WEIGHT 7. 5MT max MAX WIDTH 685mm THICKNESS 3. 1mm duration 3000mm I/L COIL OD 1800mm CTL II MIN WIDTH 30mm THICKNESS 2. 0mm LENGTH 400mm I/P COIL ID 400/500mm COIL WEIGHT 7. 5MT maxMAX WIDTH 720mm THICKNESS 6. 5mm LENGTH 3500mm I/L COIL OD 1800mm CTL III MAKE M/S GODREJ, MUMBAI MIN WIDTH 70mm THICKNESS 0. 2mm LENGTH 450mm I/P COIL ID 500mm COIL WEIGHT 7. 5MT max MAX WIDTH 720mm THICKNESS 1. 6mm LENGTH 4500mm I/L COIL OD 1800mm load Sheets and strips shall be supplied in coils or bundles of cut length or in packages each calculation not more than three tones as may be agreed the purchaser and the supplier.Sheets and strips shall be packed in water proof paper or polythene lined Hessian and securely fasten around with hoop iron. A number of coils may be bundled with wooden patterns in between or may be packed in wooden boxes. Strips may also be packed with separate thin metallic sheets wrapped around and with bands of hoop iron. &8212&8212&8212&8212&8212&8212&8212 PICKLING HR SLITTING INSPECTION RAW MATERIAL ROLLING ANNEALING undress PASS MATERIAL TESTING CR SLITTING CUT TO LENGTH PACKING &038 DESPATCH