ASTM_G_28_-_02_2015.pdf

Designation:G2802(Reapproved 2015)Standard Test Methods forDetecting Susceptibility to Intergranular Corrosion inWrought,Nickel-Rich,Chromium-Bearing Alloys1This standard is issued under the fixed designation G28;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 These test methods cover two tests as follows:1.1.1 Method A,Ferric Sulfate-Sulfuric Acid Test(Sections3 10,inclusive)This test method describes the procedurefor conducting the boiling ferric sulfate50%sulfuric acidtest which measures the susceptibility of certain nickel-rich,chromium-bearing alloys to intergranular corrosion(see Ter-minology G15),which may be encountered in certain serviceenvironments.The uniform corrosion rate obtained by this testmethod,which is a function of minor variations in alloycomposition,may easily mask the intergranular corrosioncomponents of the overall corrosion rate on alloys N10276,N06022,N06059,and N06455.1.1.2 Method B,Mixed Acid-Oxidizing Salt Test(Sections11 18,inclusive)This test method describes the procedurefor conducting a boiling 23%sulfuric+1.2%hydrochlo-ric+1%ferric chloride+1%cupric chloride test whichmeasures the susceptibility of certain nickel-rich,chromium-bearing alloys to display a step function increase in corrosionrate when there are high levels of grain boundary precipitation.1.2 The purpose of these two test methods is to detectsusceptibility to intergranular corrosion as influenced by varia-tions in processing or composition,or both.Materials shown tobe susceptible may or may not be intergranularly corroded inother environments.This must be established independently byspecific tests or by service experience.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.Warning statementsare given in 5.1.1,5.1.3,5.1.9,13.1.1,and 13.1.11.2.Referenced Documents2.1 ASTM Standards:2A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsD1193 Specification for Reagent WaterG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)3METHOD AFerric SulfateSulfuric Acid Test3.Significance and Use3.1 The boiling ferric sulfate-sulfuric acid test may beapplied to the following alloys in the wrought condition:AlloyTesting Time,hN06007120N0602224N06030120N0605924N0620024N0645524N0660024N06625120N0668624N06985120N08020120N0836724N08800120N08825A120N1027624AWhile the ferric sulfate-sulfuric acid test does detect susceptibility to inter-granular corrosion in Alloy N08825,the boiling 65%nitric acid test,PracticesA262,Practice C,for detecting susceptibility to intergranular corrosion in stainlesssteels is more sensitive and should be used if the intended service is nitric acid.3.2 This test method may be used to evaluate as-receivedmaterial and to evaluate the effects of subsequent heat treat-ments.In the case of nickel-rich,chromium-bearing alloys,thetest method may be applied to wrought and weldments ofproducts.The test method is not applicable to cast products.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 1971.Last previous edition approved in 2008 as G2802(2008).DOI:10.1520/G0028-02R15.2For 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 4.Apparatus4.1 The apparatus(Note 1)is illustrated in Fig.1.4.1.1 Allihn or Soxhlet Condenser,4-bulb,4with a 45/50ground-glass joint,overall length about 330 mm,condensingsection about 240 mm.4.1.2 Erlenmeyer Flask,1-L,with a 45/50 ground-glassjoint.The ground-glass opening shall be 40 mm wide.4.1.3 Glass Cradle(Fig.2)To pass through the ground-glass joint on the Erlenmeyer flask,the width of the cradleshould not exceed 40 mm and the front-to-back distance mustbe such that the cradle will fit the 40-mm diameter opening.Itshould have three or four holes to increase circulation of thetest solution around the specimen(Note 2).NOTE1Substitution for this equipment may not be used.Thecold-finger type