ASTM_A_918_-_06_2011.pdf

Designation:A91806(Reapproved 2011)Standard Specification forSteel Sheet,Zinc-Nickel Alloy Coated by the ElectrolyticProcess for Applications Requiring Designation of theCoating Mass on Each Surface1This standard is issued under the fixed designation A918;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification covers zinc-nickel alloy coatingsapplied by the electrolytic process to hot-rolled and cold-rolledsteel sheet.The coating has a smooth,spangle-free surface.Thezinc-nickel-coated sheet covered in this specification is pro-duced in a range of coating masses to provide coatings that arecompatible with the anticipated service life required.Thecoating mass varies,from very thin coatings that are usuallypainted to provide good service,to relatively heavy masses thatprovide good corrosion resistance in the bare(unpainted)condition.The composition range is from 9 to 16%nickel,byweight,with the balance being zinc.1.2 The product shall be coated on one or both surfaces withequal or differential coating masses on the two surfaces.Sheetcoated with equal coating masses on each surface has similarlevels of corrosion protection on each surface.Often,however,a higher level of corrosion protection is required on one surfacethan is required on the other.In these situations,one surfaceshall be specified with a heavier coating mass than the other.Either surface,when specified to be painted,will provideadditional corrosion protection as compared to an unpaintedsurface.1.3 This coating process has essentially no effect on the basemetal mechanical properties,and use is permitted on any gradeof hot-or cold-rolled steel sheet.The coated sheet is availableas Commercial Steel(CS),Drawing Steel(DS),Deep DrawingSteel(DDS),Extra-Deep Drawing Steel(EDDS),StructuralSteel(SS),High-Strength Low-Alloy Steel(HSLAS),High-Strength Low-Alloy Steel with Improved Formability(HSLAS-F),Solution-Hardened Steel(SHS),or Bake-Hardenable Steel(BHS).1.4 The values stated in SI units are to be regarded as thestandard.2.Referenced Documents2.1 ASTM Standards:2A754/A754M Test Method for Coating Weight(Mass)ofMetallic Coatings on Steel by X-Ray FluorescenceA917 Specification for Steel Sheet,Coated by the Electro-lytic Process for Applications Requiring Designation ofthe Coating Mass on Each Surface(General Require-ments)E1659 Test Methods for Coating Mass and Chemical Analy-sis of Zinc-Nickel Alloy Electrolytically Coated on SteelSheet3.Classification3.1 Coatings shall be designated as in Specification A917.The letter N shall be used to designate zinc-nickel coatings.4.Ordering Information4.1 Orders for products to this specification shall include thefollowing information,as necessary to adequately describe thedesired product:4.1.1 Name of product(electrolytic zinc-nickel alloy-coatedsteel sheet).4.1.2 ASTM designation and year of issue.4.1.3 Base metal type(hot rolled or cold rolled).4.1.4 Base metal designation Commercial Steel(CS),Drawing Steel(DS),Deep Drawing Steel(DDS),Extra-DeepDrawing Steel(EDDS),High-Strength Low-Alloy Steel(HS-LAS),High-Strength Low-Alloy with Improved Formability(HSLAS-F),Solution-Hardened Steel(SHS),or Bake-Hardenable Steel(BHS).4.1.5 Formability type,strength,grade,or class,or combi-nation thereof,as required for structural or high-strengthlow-alloy steels.4.1.6 Coating designation(see 3.1).4.1.7 Surface treatments required(see Note 1).1This specification is under the jurisdiction of ASTM Committee A05 onMetallic-Coated Iron and Steel Products and is the direct responsibility ofSubcommittee A05.11 on Sheet Specifications.Current edition approved Nov.1,2011.Published November 2011.Originallyapproved in 1993.Last previous edition approved in 2006 as A918 06.DOI:10.1520/A0918-06R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE1Steel sheet is available without surface treatment(dry)or withsurface treatments designated as chemical treatment,oiled,or phos-phatized.Unless otherwise specified sheet is furnished oiled.4.1.8 Dimensions(show thickness(minimum or nominal),width,and length,if cut lengths).4.1.9 Coil size(must include inside diameter,outside diam-eter,and maximum coil weight).4.1.10 Application(part name and description).4.1.11 Special requirements,if applicable.4.1.12 Certification,if required,heat analysis and mechani-cal property report.5.Coating Mass5.1 Coating mass shall conform to the requirements forcoating designation(mass and type)as given in Specificat