LTS 2300 COLD ROLLED (CRCA) MILD STEEL …

1 cold ROLLED (CRCA) mild STEELSHEETS, strips & COILSLTS standard specifies requirements of cold ROLLED mild STEEL sheets, strips & coils of the followinggrades :O - Ordinary - Drawing - Deep Drawing - Extra Deep Drawing SPECIFICATIONSThe ordering specification shall be as follows :i)Specification name/no. & grade,ii)Specification requirements :a) Finish : Dull or Bright,b) Oiling : Oiled or Unoiled,c) Edge : Slit edge or Mill edge,d) Other : For coils -Inside diameter,Max. outside diameter,Max. Coil weight,For Sheets-Packing )Dimensions,iv)Quantity,v)Intended use & fabricating process, if )Packing & marking requirements,vii) Delivery requirements,viii) ADOPTED BY L&T STANDARDIZATION COMMITTEEPREPARED & RELEASED BYSTANDARDS CELL, NO2,42,6,8,9,102,4,5,8,9,10 ALL2,929 LARSEN & TOUBRO LIMITED, POWAI, MUMBAI - 400 072 PAGE : 1 OF 10No copying or Extraction from this Document without L&T s PermissionLTS 2300viii)Any special conditions that must be observed in producing the ordered for paneling and other general engineering purposes including fusion and resistance welding.

2 Components with sharp bends, severe forming and deep drawing in all directions are made from DD andEDD :Fluting stretcher strains and cracking during manufacture should not exceed finish shall be matt with average surface roughness value of Ra micron Max. unlessotherwise specified in the purchase oreder. The sheets shall be free from harmful defects such asscales, rust, blisters, laminations, pitting, porosity, cracked or torn or damaged/bent edges or any otherdefects which will impair spot welding and uniform appearance of painted, electroplated and enamelledsurface. Each supply shall be accompanied by a batch test :i)Chemical Composition & Physical Properties :Chemical composition and physical properties shall be as given in table 1,2 & )n & r value :For extra deep drawing grade following n and r values shall apply : (for information only)n= mean widthr00 & r900 = - Value :The work hardening ratio, is obtained when the load - elongation curve is approximatedat =n value is generally calculated by the formula,n = log (P2/P1) + where P1 and P2 are loads,when elongation is 10% and 20% value.

3 Using standard tensile specimen, 25 mm length is accurately marked in the centre of the parallel width of the piece is measured at five positions along the 25 mm guage length and the mean width isrecorded. The test piece is then strained to approx. 15% elongation, measured on the 25 mm guage No copying or Extraction from this Document without L&T s Permission Page 2 of 10 LTS 2300 The test piece is removed from the tensile testing machine and the mean width and gauge length are accuratelymeasured. The r value is determined by using following formula : Ew log (wo/Wf)r = --------- = ----------------------------- Et Log (Lf.)

4 Where,Lo=Initial guage guage guage guage )Erichsen Cupping Values :(Applicable for thickness upto and including mm)The Erichsen cupping values for D, DD and EDD grades shall be :THICKNESS (mm)Depth of cupping (mm), )Non ageing characteristics :The EDD grades should be of non - ageing Aluminium killed quality only. The manufacturer shallguarantee the absence of stretcher strains on being cold worked, for a period of 6 months from the dateof No copying or Extraction from this Document without L&T s Permission Page 3 of 10 PermissionLTS 2300 TABLE - 1 CHEMICAL COMPOSITIONGRADECHEMICAL COMPOSITION (%) - 2 @MECHANICAL PROPERTIESGRADET ensileStrengthMpa(kg/mm2)minELONGATION (%) MIN.

5 (Guage length 50 mm)Thickness (mm) < < < < < (28)323436373839DD275 (28)343638394041 EDD275 (28)3638404142431 Mpa = kg/ mm2 NOTES tensile test values usually do not apply to D grade. However the values given in the tables shall beapplied if required by the , tensile test shall apply to thickness of mm or The table-2 applies for width of 30 mm or No copying or Extraction from this Document without L&T s Permission Page 4 of 10 LTS 2300 TABLE - 3 HARDNESS & BEND TESTGRADEHARDNESSBEND TESTHRBHV (VPN)ANGLE OFBENDINGINSIDERADIUSORDINARY (0)REF. TABLE BELOW180*tDRAWN (D)65 *CLOSEDEEP DRAWN (DD)57 *CLOSEEXTRA DEEP DRAWN (EDD) --80 - 100180*CLOSE* FOR SHEETS AND coils ONLYFOR O GRADE ONLYTEMPERDESIGNATIONHARDNESS (HRB)HARDNESS (HV)BEND TEST **MINMAXMINMAXANGLEOF BENDINSIDERADIUSHARD85--185--90*--HALF HARD758513718590*2tQUARTER HARD6075110137180*tSKIN PASSED5370100117180*CLOSEANNEALED4060901 10180*CLOSE** FOR strips ONLYNOTE.

6 I) The axis of bend shall be in the direction of )The test pieces shall be deemed to have passed the test if the outer convex surface of the test pieces isfree from )t = thickness of the test No copying or Extraction from this Document without L&T s Permission Page 5 ofLTS & on thickness on thickness of sheets :Specified NominalThickness (mm)Tolerances for Nominal Widths (mm) upto 1250>1250<1600>1600upto > > > < > < > < > < > < > < > < >above < :702-20-10595 will be in strip form of length 1235 10 No copying or Extraction from this Document without L&T s Page 6 of 10 PermissionLTS on thickness of strips / coils :Specified NominalThickness (mm)Tolerances for Nominal Widths (mm) 80>80 125>125 250>250 450>450upto > > > > > > > > > > > > > No copying or Extraction from this Document without L&T s Permission Page 7 of10 LTS on width of slitted coils /strip :Pl.

7 Refer LTS on width of sheet :WIDTH OF sheet (mm)TOLERANCE (mm) 1250+ >1250+10, Tolerance on length of coils / strips :LENGTH OF sheet (mm)TOLERANCE (mm) 2000+15,-0>2000+ of length, Tolerances :The maximum difference between the largest warpage and the flat horizontal surface on which the sheetis made to rest minus the thickness of NominalThickness (mm)TOLERANCE OF SPECIFIED WIDTH / LENGTH (mm)upto 1200>>1200 1500>>1500upto > No copying or Extraction from this Document without L&T s Permission Page 8 of 10 LTS camber for slitted coils / strips :Pl. refer LTS on Length of sheet :Maximum permissible camber on 2500mm long sheet shall be 4 variation shall be allowed over any portion of 2000 mm or the length of the sheet /strip,whichever is of squareness :Out of squareness is the greatest deviation on an edge from a straight line at right angles to a side andtouching one of squareness - of width & TESTINGA fter ascertaining that a valid test certificate is available, the sheets shall be inspected/tested for :i)Visual defect as per )Physical, Chemical & other properties as per )Dimensions & Tolerances as per )Coil Packing :The coils shall be packed as per LTS 1026 unless otherwise ) sheet Packing.

8 Each packet to be packed in standard metal clad STEEL packets with waterproof paper covering onwooden skids. Weight of each packet shall be max. 3 MT gross except for X 1030 X 1640 & X920 X 1730 mm which shall be max. 2MT sheet /coil shall be treated on both sides with non-hardening type rust preventive oil, which can beeasily washed with aqueous alkali shall be legibly marked on top of each bundle or packet of sheets or shown on the tagattached to each name or trade mark, if & Identification mark by which sheets or strips may be traced to case or cast from which theywere No copying or Extraction from this Document without L&T s Permission Page 9 of 10