IS 1786 (2008): High strength deformed steel bars and ...

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2 > 0 B Bhart hari N ti atakam Knowledge is such a treasure which cannot be stolen Invent a New India Using Knowledge is 1786 ( 2008 ): high strength deformed steel bars and wiresfor concrete reinforcement- [CED 54: ConcreteReinforcement]IS1786:2008ik,Indi anStandardHIGHSTRENGTHDEFORMEDSTEELBARSA NDWIRESFORCONCRETEREINFORCEMENT SPECIFICATION(FourthRevision)I( ; $ @BIS2008 BUREAUOFINDIANSTANDARDSMANAKBHAVAN,9 BAHADURSHAHZAFARMARGNEWDELHI110002 May2008 PriceGroup6 ConcreteReinforcementSectionalCommittee, CED54 FOREWORDThisIndianStandard(FourthRevisio n)wasadoptedbytheBureauofIndianStandards , , ,thetitleofthestandardwasmodifiedto Specificationforcold-workedsteelhighstre ngthdeformedbarsforconcretereinforcement .)

3 Inthethirdrevision,IS1139:1966 Specificationforhotrolledmildsteel,mediu mtensilesteelandhighyieldstrengthsteelde formedbarsforconcretereinforcement wasmergedinthestandardandthetitlewasmodi fiedto Specificationforhighstrengthdeformedstee lbarsandwiresforconcretereinforcement . ,Thisrevisionincorporatesthepropertiesof highstrengthdeformedsteelbarsandwires, :a) ) )Anewparameter percentagetotalelongationatmaximumforce ) , ,i)Mechanicaltestingofmetals Tensiletesting16086892ii)Methodsforbendt est15997438and15630-1iii) ,thefinalvalue,observedorcalculated,expr essingtheresultofatestoranalysis,shallbe roundedoffinaccordancewithIS2:1960 Rulesforroundingoffnumericalvalues(revis ed) .Thenumberofsignificantplacesretainedint heroundedoffvalueshouldbethesameasthatof thespecifiedvalueinthisstandard.

4 AMENDMENT NO. 1 NOVEMBER 2012 TOIS 1786 : 2008 high strength deformed bars AND WIRESFOR CONCRETE REINFORCEMENT SPECIFICATION(Fourth Revision)(Second cover page, Foreword) Insert the following after sixth para as a separate para: Provisions in this standard are at variance with similarprovisions in ISO 6935-2 : 2007 steel for thereinforcement of concrete Part 2: Ribbed bars , in view of the following:a)Geographical factors which determine the earthquake zoning and consequently the structural designconsiderations, structural design method/principles adopted, the design parameters and the requiredmaterial properties;b)Technological factors associated with the process of manufacture of the product (such as throughsecondary processes/induction furnace), which influence the product characteristics (like chemicalcomposition and mechanical properties like yield strength , tensile strength , elongation, ductility, etc);andc)Construction techniques and practices adopted in this country, the equipments used and the skill levelof construction workers which also influence the product characteristics (such as bend and bondstrength).

5 The major deviations are:a)The steel grades covered are at variance. This standard covers requirements for high strength bars onlywhereas ISO 6935-2 also covers bars of lower tensile )Chemical compositions vary from that in ISO )Mechanical properties specified in this standard are individual values, whereas the tensile properties inISO 6935-2 are primarily the specified characteristic )Bend and re-bend test requirements vary from those in ISO )Bond requirements in this standard are specified on basis of mean area of ribs whereas therequirements in ISO 6935-2 are for rib geometry. This standard additionally specifies pull out test as arequirement for approval of new or amended rib geometry. (Page 1, ) Substitute the followingfor the existing clause: standard covers the requirements of deformed steel bars andwires for use as reinforcement inconcrete, in the following strength grades:a)Fe 415, Fe 415D, Fe 415S;b)Fe 500, Fe 500D, Fe 500S;c)Fe 550, Fe 550D; andd)Fe figures following the symbol Fe indicate the specified minimum percentproof stress or yield stress, in letters D and S following the strength grade indicates the categories with same specifiedminimum percent proof stress/yieldstress but with enhanced and additional requirements.

6 (Page 2, ) Substitute the followingforthe existing clause: ladle analysis of steel for various grades, when carried out by the method specified in the relevantparts of IS 228 or any other established instrumental/chemical method, shall have maximumpermissiblepercentage ofconstituents as follows. In case of dispute, the procedure given in IS 228 and its relevant partsPrice Group21 Amend : 2008shall be thereferee method and where test methods are not specified shall be as agreed to between the purchaserand the Percent, MaximumFe 415Fe 415 DFe 415 SFe 500Fe 500 DFe 500 SFe 550Fe 550 DFe and guaranteed weldability, the Carbon Equivalent, CE using the formula: CrMoVNiCuMnCEC6515 shall not be more than percent, when micro-alloy/low alloys are used.

7 When micro-alloys/low alloysare not used,carbon equivalent using the formula:MnCEC6 shall not be more than percent. Reinforcement bars /wires with carbon equivalent above percent should, howeverbe welded with precaution. Use of low hydrogen basic coated electrodes with matching strength bars /wires of micro-alloying elements is not mandatory for any of the above grades. When strengthening elements like Nb,V, B and Ti are used individually or in combination, the total contents shall not exceed percent; in such casemanufacturer shall supply the purchaser or his authorized representative a certificate stating that the total contents of thestrengthening elements in the steel do not exceed the specified steel may also be producedby adding alloying elements like Cr, Cu, Ni,Mo and P, either individually or incombination, to improve allied product properties.

8 However, the total content of these elements shall not be less In such case,themanufacturers shall supply the purchaser or his authorized representative a test certificate statingthe individual contents of all the alloying elements. In such low alloy steels when phosphorus is used, it shall not percent and when used beyond the limit , the carbon shall be restricted to a maximum of percent,and in such case the restriction to maximum content of sulphur and phosphorus as given and the condition ofminimum alloy content percent shall not may note that there is a danger of pitting and crevice corrosion when weathering steels (that is those with chemicalcomposition conforming to IS 11587) are embedded in chloride contaminated concrete.

9 4 Nitrogen content of the steel should not exceed percent (120 ppm), which shall be ensured by the manufacturer byoccasional check analysis. Higher nitrogen contents up to percent (250 ppm) may be permissible provided sufficientquantities of nitrogen binding elements, like Nb, V, Ti, Al, etc, are present. In order to ascertain whether sufficientquantities of nitrogen binding elements are present, following formula may be used, where all elements are in ppm. freeAlTiVNbN 12010714 2 Amend to IS1786 : 2008 (Page 4, ) Substitute the following for the existing clause: nominal sizes of bars /wires shall be as follows:Nominal size, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 28 mm, 32 mm, 36 mm,40 mm, 45 mm, 50 Other sizes may be supplied by mutual agreement.

10 (Page 4,Table 1) Insert the following at the end of theTable 1:Sl SizemmCross Sectional Areamm2 Mass per Metrekg(1)(2)(3)(4)xiv) ) (Page 6,Table 3) Substitute the following for the existingTable 3:Table 3 Mechanical Properties of high StrengthDeformed bars and Wires(Clause )Sl 415 DFe415 SFe500Fe500 DFe500 SFe550Fe550 DFe600(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11 )i) percent proof stress/ yieldstress,Min, ) percent proof stress/ yieldstress,Max, N/mm2 iii)TS/YS ratio1), N/mm2 , butTSnot lessthan , butTSnot lessthan , butTSnot lessthan , butTSnot lessthan , butTSnot lessthan 585N/mm2 , butTSnot lessthan , butTSnot lessthan 660N/mm2iv)Elongation, percent, min. ongauge length A, whereA isthe cross-sectional area of thetest )Total elongation at maximumforce, percent,Min, on gaugelength A, whereA is thecross-sectional area of the testpiece ( ) 2) 510 58 5 1) TS/YS ratio refers to ratio of tensile strength to the percent proof stress or yield stress of the test piece2) Test, wherever specified by the purchaser.