1、Designation:G10894(Reapproved 2015)Standard Test Method forElectrochemical Reactivation(EPR)for DetectingSensitization of AISI Type 304 and 304L Stainless Steels1This standard is issued under the fixed designation G108;the number immediately following the designation indicates the year oforiginal ad
2、option 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 test method covers a laboratory procedure forconducting an electrochemic
3、al reactivation(EPR)test on AISIType 304 and 304L(UNS No.S30400 and S30403,respec-tively)stainless steels.This test method can provide a nonde-structive means of quantifying the degree of sensitization inthese steels(1,2,3).2This test method has found wideacceptance in studies of the effects of sens
4、itization on inter-granular corrosion and intergranular stress corrosion crackingbehavior(see Terminology G15).The EPR technique has beensuccessfully used to evaluate other stainless steels and nickelbase alloys(4),but the test conditions and evaluation criteriaused were modified in each case from t
5、hose cited in this testmethod.1.2 The values stated in SI units are to be regarded as thestandard.The inch-pound units given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the us
6、er 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:3A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsD1193 Specifica
7、tion for Reagent WaterE3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE112 Test Methods for Determining Average Grain SizeG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG3 Practice for Conventions Applicable to ElectrochemicalMe
8、asurements in Corrosion TestingG5 Reference Test Method for Making PotentiodynamicAnodic Polarization MeasurementsG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)4G28 Test Methods for Detecting Susceptibility to Inter-granular Corrosion in Wrought,Nickel-Rich,Chromium-Bea
9、ring AlloysG61 Test Method for Conducting Cyclic PotentiodynamicPolarization Measurements for Localized Corrosion Sus-ceptibility of Iron-,Nickel-,or Cobalt-Based Alloys3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 integrated charge(Q)the charge measured,incoulombs,during rea
10、ctivation as given by the time integral ofcurrent density below the reactivation peak of the curve.3.1.2 maximum anodic current density(Ir)the currentdensity measured at the peak of the anodic curve duringreactivation.3.1.3 normalized charge(Pa)the integrated current nor-malized to the specimen size
11、 and grain size.Parepresents thecharge(in coulombs/cm2)of the grain-boundary area.Themethod for calculating Pais given in 9.2.3.1.4 reactivationin the electrochemical reactivation(EPR)test,the potential sweep from the passivation potentialreturning to the corrosion potential.3.1.5 scan ratethe rate
12、at which the electrical potentialapplied to a specimen in a polarization test is changed.4.Summary of Test Method4.1 The EPR test is accomplished by a potentiodynamicsweep from the passive to the active regions of electrochemicalpotentials in a process referred to as reactivation.The EPR test1This t
13、est method is under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and is the direct responsibility of Subcommittee G01.11 onElectrochemical Measurements in Corrosion Testing.Current edition approved Nov.1,2015.Published December 2015.Originallyapproved in 1992.Last previous edition ap
14、proved in 2010 as G10894(2010).DOI:10.1520/G0108-94R15.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards
15、volume information,refer to the standards Document Summary page onthe ASTM website.4The 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 measures the amount of
16、charge associated with the corrosion ofthe chromium-depleted regions surrounding chromium carbideprecipitated particles.Most of these particles in a sensitizedmicrostructure are located at grain boundaries(see Terminol-ogy E7).Discrete particles located within the grain(referred toas intragranular precipitates)will also contribute to the totalmeasured charge.Therefore,it is important to examine thealloy microstructure following an EPR test,to determine therelative proportion of corrosion site as
