GB/T228-20022002310200271ISO68921998GB/T228-1987GB/T3076-1982GB/T6397-1986GB/T228-2002PercentagereductionofareaZPercentageelongationafterfractureAA11.3Axmm510xmmPercentagetotalelongationatfractureAt--PercentageelongationatmaximumforceAgtgtPercentagenon-proportionalelongationatmaximumforceAggPercentageyieldpointextensionAesYieldstrength-sUpperyieldstrengthReHsULoweryieldstrengthReLsLProofstrength,non-proportionalextensionRpRp0.2pp0.2Proofstrength,totalextensionRtRt05tt0.5PermanentsetstrengthRrRr0.2rr0.2TensilestrengthRmb