ASTM_G_48_-_11_2015.pdf

Designation:G4811(Reapproved 2015)Standard Test Methods forPitting and Crevice Corrosion Resistance of StainlessSteels and Related Alloys by Use of Ferric ChlorideSolution1This standard is issued under the fixed designation G48;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover procedures for the determina-tion of the resistance of stainless steels and related alloys topitting and crevice corrosion(see Terminology G15)whenexposed to oxidizing chloride environments.Six proceduresare described and identified as Methods A,B,C,D,E,and F.1.1.1 Method AFerric chloride pitting test.1.1.2 Method BFerric chloride crevice test.1.1.3 Method CCritical pitting temperature test for nickel-base and chromium-bearing alloys.1.1.4 Method DCritical crevice temperature test fornickel-base and chromium-bearing alloys.1.1.5 Method ECritical pitting temperature test for stain-less steels.1.1.6 Method FCritical crevice temperature test for stain-less steels.1.2 Method A is designed to determine the relative pittingresistance of stainless steels and nickel-base,chromium-bearing alloys,whereas Method B can be used for determiningboth the pitting and crevice corrosion resistance of these alloys.Methods C,D,E and F allow for a ranking of alloys byminimum(critical)temperature to cause initiation of pittingcorrosion and crevice corrosion,respectively,of stainlesssteels,nickel-base and chromium-bearing alloys in a standardferric chloride solution.1.3 These tests may be used to determine the effects ofalloying additives,heat treatment,and surface finishes onpitting and crevice corrosion resistance.1.4 The values stated in SI units are to be regarded as thestandard.Other units are given in parentheses for informationonly.1.5 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:2A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsD1193 Specification for Reagent WaterE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1338 Guide for Identification of Metals and Alloys inComputerized Material Property DatabasesG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)3G46 Guide for Examination and Evaluation of Pitting Cor-rosionG107 Guide for Formats for Collection and Compilation ofCorrosion Data for Metals for Computerized DatabaseInput3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 critical crevice temperature,nthe minimum tem-perature(C)to produce crevice attack at least 0.025-mm(0.001-in.)deep on the bold surface of the specimen beneaththe crevice washer,edge attack ignored.3.1.2 critical pitting temperature,nthe minimum tem-perature(C)to produce pitting attack at least 0.025-mm(0.001-in.)deep on the bold surface of the specimen,edgeattack ignored.3.2 The terminology used herein,if not specifically definedotherwise,shall be in accordance with Terminology G15.1These test methods are under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and are the direct responsibility of Subcommittee G01.05 onLaboratory Corrosion Tests.Current edition approved Nov.1,2015.Published November 2015.Originallyapproved in 1976.Last previous edition approved in 2011 as G4811.DOI:10.1520/G0048-11R15.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Definitions provided herein and not given in Terminology G15are limited only to this standard.4.Significance and Use4.1 These test methods describe laboratory tests for com-paring the resistance of stainless steels and related alloys to theinitiation of pitting and crevice corrosion.The results may beused for ranking alloys in order of increasing resistance topitting and crevice corrosion initiation under the specificconditions of these methods.Methods A and B are designed tocause the breakdown of Type 304 at room temperature.4.2 The use of ferric chloride solutions is justified because itis related to,but not the same as,that within a pit or crevice siteon a ferrous alloy in chloride bearing environm