ASTM_G_161_-_00_2013.pdf

Designation:G16100(Reapproved 2013)Standard Guide forCorrosion-Related Failure Analysis1This standard is issued under the fixed designation G161;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 guide covers key issues to be considered whenexamining metallic failures when corrosion is suspected aseither a major or minor causative factor.1.2 Corrosion-related failures could include one or more ofthe following:change in surface appearance(for example,tarnish,rust,color change),pin hole leak,catastrophic struc-tural failure(for example,collapse,explosive rupture,implo-sive rupture,cracking),weld failure,loss of electricalcontinuity,and loss of functionality(for example,seizure,galling,spalling,swelling).1.3 Issues covered include overall failure site conditions,operating conditions at the time of failure,history of equipmentand its operation,corrosion product sampling,environmentalsampling,metallurgical and electrochemical factors,morphol-ogy(mode)or failure,and by considering the preceding,deducing the cause(s)of corrosion failure.1.4 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:2E3 Guide for Preparation of Metallographic SpecimensE1459 Guide for Physical Evidence Labeling and RelatedDocumentationE1492 Practice for Receiving,Documenting,Storing,andRetrieving Evidence in a Forensic Science LaboratoryG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG46 Guide for Examination and Evaluation of Pitting Cor-rosion3.Significance and Use3.1 This guide is intended to assist those encounteringcorrosion or possible corrosion as a causative factor in a failureanalysis.3.2 This guide is not an absolute plan that will identify thecause of corrosion in all failure analyses.3.3 This guide is intended to help an investigator identifysignificant sources and types of corrosion information that maybe available for failure analysis.3.4 Appendix X1 contains a checklist that is intended toassist in corrosion-related failure evaluations.4.Organizing the Analysis4.1 Early recognition of corrosion as a factor in a failureanalysis is critical to any such investigation.Therefore,it isgenerally desirable to conduct the analysis as soon as possibleafter the apparent failure.It is always desirable to protect thephysical evidence until the analysis can begin.Much importantcorrosion information can be lost if a failure scene is altered orchanged before appropriate observations can be made.4.2 A written plan for the detailed analysis should beprepared.The plan may include methods of documentation(photographs before and during analysis,sketches,statements),responsibilities of parties,reporting needs,and scheduling.4.3 If the capability(corrosion knowledge and experience)of in-house personnel and availability of resources are inad-equate to make the analysis in a timely manner,it may beexpedient to seek third party services.5.Failure Site Conditions5.1 When possible,an overall examination of the conditionsat a failure site prior to cleaning,moving,or sampling debrisshould be conducted.Impressions as to physical arrangements,odors,colors,textures,and conditions of adjacent structurescan provide important clues as to active corrosion processes.5.2 Photographs or videotapes serve as documentation ofthe observations.Color photographs are preferable.It is helpfulto include labels and indications of size,location,and orienta-tion in the photographs.Photographs before,during,and aftersampling are recommended.1This guide is under the jurisdiction of ASTM Committee G01 on Corrosion ofMetals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Current edition approved May 1,2013.Published July 2013.Originally approvedin 1999.Last previous edition approved in 2006 as G161 00(2006).DOI:10.1520/G0161-00R13.2For 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 5.3 Sketches and drawings with notes as to detailed obser-vations can be beneficial for later evaluations.Locations ofsamples and photographs may be shown.5.4 Interviews with those who were present or nearby whenthe failure occurred would be appropriate.Information on time,sights,sounds,and conditions can be gained during suchinterviews.6