GBT 1591-2008标准（英文版）

390≤0.46≤0.48≤0.49Q420≤0.48≤0.50≤0.52Q460≤0.53≤0.54≤0.55Table4CarbonEquivalentValueofSteelsDeliveredatThermomechanicalRolling(TMCP)orThermomechanicalRolling+TemperingStateGradeCarbonequivalentvalue(CEV)/%Normalthickness≤63mmNormalthicknessordiameter>63mm-120mmNormalthickness>120mm-150mmQ345≤0.44≤0.48≤0.48Q390≤0.46≤0.48≤0.49Q420≤0.48≤0.50≤0.52Q460≤0.53≤0.54≤0.55Q500≤0.47≤0.48≤0.48Q550≤0.47≤0.48≤0.48Q620≤0.48≤0.49≤0.49Q690≤0.49≤0.49≤0.496.1.9Whenthecarboncontentofsteelsdeliveredatthermomechanicalrolling(TMCP)orthermomechanicalrolling+temperingstateisnobiggerthan0.12%,thesolderabilityofsteelsmaybeevaluatedbytheweldingcracksensitivityindex(Pcm)inplaceofcarbonequivalentvalue.ordingtoFormula(2)positionsanditsvalueshallmeettheprovisionsofTable5.Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/1S+V/10+5B(2)