ASTM_G_66_-_99_2013.pdf

Designation:G6699(Reapproved 2013)Standard Test Method forVisual Assessment of Exfoliation Corrosion Susceptibility of5XXX Series Aluminum Alloys(ASSET Test)1This standard is issued under the fixed designation G66;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 This test method covers a procedure for continuousimmersion exfoliation corrosion testing of 5XXX seriesaluminum-magnesium alloys containing 2.0%or more mag-nesium.1.2 This test method applies only to wrought products.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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ASTM Standards:2D1193 Specification for Reagent WaterG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)32.2 ASTM Adjuncts:ASSET Tested Specimens(Glossy Prints)43.Terminology3.1 Definitions:3.1.1 exfoliationcorrosion that proceeds laterally from thesites of initiation along planes parallel to the surface,generallyat grain boundaries,forming corrosion products that forcemetal away from the body of the material,giving rise to alayered appearance(see Terminology G15).4.Summary of Test Method4.1 Specimens are immersed for 24 h at 65 6 1C(150 62F)in a solution containing ammonium chloride,ammoniumnitrate,ammonium tartrate,and hydrogen peroxide.The sus-ceptibility to exfoliation is determined by visual examinationusing performance ratings established by reference to standardphotographs.5.Significance and Use5.1 This test method provides a reliable prediction of theexfoliation corrosion behavior of Al-Mg alloys in marineenvironments.5,6,7The test is useful for alloy developmentstudies and quality control of mill products such as sheet andplate.6.Apparatus6.1 Any suitable glass or plastic container can be used tocontain the solution and specimens during the test period.Depending upon the shape and size of the specimens,rods orracks of glass,plastic,or other inert substance shall be used tosupport the specimens above the bottom of the container.Thecontainer should be fitted with a removable cover to reduceevaporation.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.7.2 Purity of WaterDistilled or deionized water conform-ing to Specification D1193.Type IV shall be used to preparethe test solution except chloride ion sodium limits can bedisregarded.1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and is the direct responsibility of Subcommittee G01.05 onLaboratory Corrosion Tests.This method was developed by a joint task group withThe Aluminum Assoc.,Inc.Current edition approved May 1,2013.Published July 2013.Originally approvedin 1980.Last previous edition approved in 2005 as G66 99(2005).DOI:10.1520/G0066-99R13.2For 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.4Available from ASTM International Headquarters.Order Adjunct No.ADJG0066.Original adjunct produced in 1987.5Aluminum Association Technical Report T1,“Exfoliation Corrosion Testing ofAluminum Alloys 5086 and 5456”.6Sprowls,D.O.,Walsh,J.D.and Shumaker,M.B.,“Simplified ExfoliationTesting ofAluminumAlloys”,Localized CorrosionCause of Metal Failure,ASTMSTP 516,ASTM,1972,pp 3865.7Summerson T.J.,Interim Report,Aluminum Association Task Group onExfoliation and Stress Corrosion Cracking of Aluminum Alloys for Boat Stock;Proceedings Tri-Service Corrosion Military Equipment Conference,October 2931,1974;Technical Report AFML-TR-75-42,Vol.II,p.193221,February 1,1975.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.Test Solution8.1 Preparation of Test Solution:8.1.1 The test solution shall have the following composi-tion:NH4Cl(1.0 M)NH4NO3(0.25 M)(NH4)2C4H4O6(0.01 M)H2O2(0.09 M)8.1.2 Dissolve 53.5 g ammonium chloride(NH4Cl),20.0 gammonium nitrate(NH4NO3),1.8 g ammonium tartrate(NH4)2C4H4O6),and 10 mL of 30%stock solution hydrogenperoxide(H2O2)in a small amount of water.After dissolving,mix the components together thoroughly and adjust the finaldilution to 1 L.NOTE1If a stock solution of the above chemicals is to be stored,thehydrogen peroxide should not be added until the solution is heated for thetest.8.2 The