ASTM_A_143_-_A_143M_-_07_2014.pdf

Designation:A143/A143M07(Reapproved 2014)Standard Practice forSafeguarding Against Embrittlement of Hot-Dip GalvanizedStructural Steel Products and Procedure for DetectingEmbrittlement1This standard is issued under the fixed designation A143/A143M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This practice covers procedures that can be followed tosafeguard against the possible embrittlement of steel hot-dipgalvanized after fabrication,and outlines test procedures fordetecting embrittlement.Conditions of fabrication may inducea susceptibility to embrittlement in certain steels that can beaccelerated by galvanizing.Embrittlement is not a commonoccurrence,however,and this discussion does not imply thatgalvanizing increases embrittlement where good fabricatingand galvanizing procedures are employed.Where history hasshown that for specific steels,processes and galvanizingprocedures have been satisfactory,this history will serve as anindication that no embrittlement problem is to be expected forthose steels,processes,and galvanizing procedures.1.2 This practice is applicable in either inch-pounds or SIunits.Inch-pounds and SI units are not necessarily exactequivalents.Within the text of this practice and whereappropriate,SI units are shown in brackets.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F606 Test Methods for Determining the Mechanical Proper-ties of Externally and Internally Threaded Fasteners,Washers,and Rivets(Metric)F0606_F0606M3.Terminology3.1 Definitions:3.1.1 embrittlement,nthe loss or partial loss of ductility ina steel where an embrittled product characteristically fails byfracture without appreciable deformation;types of embrittle-ment usually encountered in galvanized steel are related toaging phenomena,cold working,and absorption of hydrogen.4.Factors in Embrittlement4.1 Embrittlement or loss of ductility in steel is oftenassociated with strain-aging.Strain-aging refers to the delayedincrease in hardness and strength,and loss of ductility andimpact resistance which occur in susceptible steels as a resultof the strains induced by cold working.The aging changesproceed slowly at room temperature,but proceed at an accel-erated rate as the aging temperature is raised and may occurrapidly at the galvanizing temperature of approximately 850F455C.4.2 Hydrogen embrittlement may also occur due to thepossibility of atomic hydrogen being absorbed by the steel.Thesusceptibility to hydrogen embrittlement is influenced by thetype of steel,its previous heat treatment,and degree ofprevious cold work.In the case of galvanized steel,the acidpickling reaction prior to galvanizing presents a potentialsource of hydrogen.However,the heat of the galvanizing bath1This practice is under the jurisdiction of ASTM Committee A05 on Metallic-Coated Iron and Steel Products and is the direct responsibility of SubcommitteeA05.13 on Structural Shapes and Hardware Specifications.Originally Prepared by Subcommittee A05.10 on Embrittlement Investigation ofCommittee A05 on Corrosion of Iron and Steel and based on an investigation madeby Battelle Memorial Institute under American Society for Testing and Materialssponsorship.See Proceedings,Am.Soc.Testing Mats.,Vol 31,Part I,1931,p.211;also paper by Samuel Epstein,“Embrittlement of Hot-Dip Galvanized StructuralSteel,”see Proceedings,Am.Soc.Testing Mats.,Vol 32,Part II,1932,p.293.Current edition approved Aug.1,2014.Published September 2014.Originallyapproved in 1932.Last previous edition approved in 2007 as A143/A143M 07.DOI:10.1520/A0143_A0143M-07R14.2For 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 partially expels hydrogen that may have been absorbed.Inpractice hydrogen embrittlement of galvanized steel is usuallyof concern only if the steel exceeds approximately 150 ksi1100 MPa in ultimate tensile strength,or if it has beenseverely cold worked prior to pickling.4.3 Loss of ductility of cold-worked steels is dependent onmany factors including the type of steel(strength level,agingcharacteristics),thickness of steel,and degree of cold work,and is accentuated by areas of stress concen