【英文标准名称】:StandardTestMethodforDeterminingtheSusceptibilitytoIntergranularCorrosionof5XXXSeriesAluminumAlloysbyMassLossAfterExposuretoNitricAcid(NAMLTTest)
【原文标准名称】:用接触硝酸环境之后的重量损失来测定5XXX系列铝合金晶间腐蚀敏感性的标准试验方法(NAMLT试验)
【标准号】:ASTMG67-2004
【标准状态】:现行
【国别】:
【发布日期】:2004
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:G01.05
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:粒间腐蚀;硝酸;灵敏性;试验;铝;磨损;测定;合金;腐蚀;金属
【英文主题词】:5xxxaluminumalloys;aluminumalloys;grainboundarysensitization;intercrystallinecorrosion;intergranularcorrosion;massloss;nitricacid;pittingcorrosion
【摘要】:ThistestmethodprovidesaquantitativemeasureofthesusceptibilitytointergranularcorrosionofAl-MgandAl-Mg-Mnalloys.Thenitricaciddissolvesasecondphase,analuminum-magnesiumintermetalliccompound(x03B2;Al-Mg),inpreferencetothesolidsolutionofmagnesiuminthealuminummatrix.Whenthiscompoundisprecipitatedinarelativelycontinuousnetworkalonggrainboundaries,theeffectofthepreferentialattackistocorrodearoundthegrains,causingthemtofallawayfromthespecimens.Suchdroppingoutofthegrainscausesrelativelylargemasslossesoftheorderof25to75mg/cm2(160to480mg/in2),whereas,samplesofintergranular-resistantmaterialsloseonlyabout1to15mg/cm2(10to100mg/in2).Whenthex03B2;Al-Mgcompoundisrandomlydistributed,thepreferentialattackcanresultinintermediatemasslosses.Metallographicexaminationisrequiredinsuchcasestoestablishwhetherornotthelossinmassistheresultofintergranularattack.Theprecipitationofthesecondphaseinthegrainboundariesalsogivesrisetointergranularcorrosionwhenthematerialisexposedtochloride-containingnaturalenvironments,suchasseacoastatmospheresorseawater.Theextenttowhichthealloywillbesusceptibletointergranularcorrosiondependsuponthedegreeofprecipitatecontinuityinthegrainboundaries.Visiblemanifestationsoftheattackmaybeinvariousformssuchaspitting,exfoliation,orstress-corrosioncracking,dependinguponthemorphologyofthegrainstructureandthepresenceofsustainedtensilestress.31.1Thistestmethoddescribesaprocedureforconstantimmersionintergranularcorrosiontestingof5XXXseriesaluminumalloys.1.2Thistestmethodisapplicableonlytowroughtproducts.1.3Thistestmethodcoverstypeofspecimen,specimenpreparation,testenvironment,andmethodofexposure.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:H25
【国际标准分类号】:
【页数】:3P.;A4
【正文语种】: