IS 4759 (1996): Hot-dip zinc coatings on structural steel ...

1 Disclosure to Promote the Right To InformationWhereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

2 ! $ ' + - Satyanarayan Gangaram Pitroda Invent a New India Using Knowledge 0 1 ' 5 Jawaharlal Nehru Step Out From the Old to the New 1 + , 1 + Mazdoor Kisan Shakti Sangathan The Right to Information, The Right to Live ! > 0 B Bhart hari N ti atakam Knowledge is such a treasure which cannot be stolen Invent a New India Using Knowledge IS 4759 (1996): Hot-dip zinc coatings on structural steeland other allied products [MTD 7: Light Metals and theirAlloys]IS 4759 : 1996(Reaffirmed 2001)Edition (2002-05)Indian StandardHOT-DIP ZINC coatings ONSTRUCTURAL steel AND OTHER ALLIEDPRODUCTS SPECIFICATION( Third Revision )(Incorporating Amendment No.)

3 1)ICS ;77 : BIS 2002B U R E A U O F I N D I A N S T A N D A R D SMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARGNEW DELHI 110002 Price Group 3 Metallic and Non-Metallic Finishes Sectional Committee, MTD 20 FOREWORDThis Indian Standard (Third Revision) was adopted by Bureau of Indian Standards, after the draftfinalized by the Metallic and Non-Metallic Finishes Sectional Committee had been approved bythe Metallurgical Engineering Division standard was initially published in 1968 and was subsequently revised in 1979 and reviewing the standard the committee decided to revise the same.

4 The followingmodifications have been made in this revision :a) Additional grade of zinc has been specified;b) Guidelines on the properties of the articles to be coated that affect the results of Hot-DipCoatings have been incorporated;c) A new clause on information to be given by the purchaser to the galvanizer have been added;andd) Requirements of of IS 4759 : 1984 have been covered in of this this revision assistance has also been derived from Doc CEN/TC, 262/SCI/WG2/N27 Hot DipCoatings on Fabricated Ferrous Products , issued by European Committee for edition incorporates Amendment No.

5 1 (May 2002). Side bar indicates modification of thetext as the result of incorporation of the the purpose of deciding whether a particular requirement of this standard is complied with,the final value, observed or calculated expressing the result of a test or analysis, shall be roundedoff in accordance with IS 2 : 1960 Rules for rounding off numerical values (revised) . The numberof significant places retained in the rounded off value should be the same as that of the specifiedvalue in this standard. IS 4759 : 19961 Indian StandardHOT-DIP ZINC coatings ONSTRUCTURAL steel AND OTHER ALLIEDPRODUCTS SPECIFICATION( Third Revision )1 standard specifies requirements forzinc coating applied by Hot-dip galvanizing oniron and steel products, fabricated orassembled from cast, rolled, pressed and forgedshapes, such as structural steel sections, platesand standard makes no reference to thequality of iron and steel itself before hot-dipgalvanizing.

6 However guidance on thecondition of the base material which may affectthe result of Hot-dip galvanizing are given inAnnex REFERENCEThe Indian Standards listed at Annex B arenecessary adjuncts to this SUPPLY OF MATERIALG eneral requirements relating to the supply ofmaterial shall conform to IS 1387 : GENERAL Quality of ZincZinc used for galvanizing shall conform to anyof the grades specified in IS 209 : 1992 Zincingot or IS 13229 : 1991 Zinc for Galvanizing . Galvanizing BathThe molten metal in the galvanizing bath shallcontain not less than percent by mass ofzinc, but where there is a special userrequirement, levels or addition of impurities inthe bath or in the coating may be specified bythe GalvanizingThe steel products may, as far as practicable,be galvanized in accordance with IS 2629 INFORMATION TO BE SUPPLIED BY THE PURCHASER TO THE Hot-dip Essential InformationThe following information shall be supplied bythe purchaser to the Hot-dip galvanizer.

7 A) Number of this Indian standard, andb) The composition and any properties of thebase metal that may affect Any other information Additional InformationThe following information may be required forparticular purpose and if so shall be specifiedby the purchaser:a) An identification of significant surfaces,for example by drawings or by theprovision of suitably marked ) A drawing or other means of identifyingsurface unevenness; for example rounddrops or contact marks, will make thecoated article unacceptable for itsintended ) A sample or other means of showing thefinished ) Any special thickness of coating (seeAnnex A ).

8 NOTE Any other information like:6 COATING Mass of Zinc CoatingRequirements for the mass of the coating fordifferent classes of materials are given inTable ) Designation of steel ;ii) Description regarding size length, etc;iii) Condition of delivery;iv) Any special requirement; andv) Test report (if required) may be supplied by thepurchaser to the Hot-dip ) Designation of steel ;ii) Description regarding size, length, etc;iii) Condition of delivery;iv) Any other special requirements; andv) Test report (if required) may be supplied by thepurchaser to the Hot-dip galvanizer.

9 IS 4759 : 19962 Table 1 Mass of Zinc Coating(Clause ) Freedom from DefectsThe zinc coating shall be uniform, adherent,reasonably smooth and free from suchimperfections as flux, ash bare patches, blackspots, pimples, lumpiness, runs, rust stains,bulky white deposits and steel EmbrittlementThe design of the products and the selection ofthe steel for its suitability to withstand normalgalvanizing operations without embrittlementor the method of fabrication shall be theresponsibility of the Recommended precautions to properly design,fabricate and prepare the material for galvanizing toprevent embrittlement are given in IS 6158 : POST-TREATMENTMost galvanized products do not require anypost-treatment.

10 Wherever required by thepurchaser, treatment such as chromating orphosphating may be applied to reduce the riskof wet storage staining or assist subsequentpainting SAMPLING AND CRITERIA FOR CONFORMITYU nless otherwise agreed to, the followingsampling plan shall be followed for ascertainingthe conformity of galvanized coating onstructural steel and other allied LotAll the material of the same type in a coatingbath having uniform coating characteristicsshall be grouped together to constitute a lot shall be tested separately for thevarious requirements of the specification.