... -1991, GB 4357-89 1.Steel Grade: 45#, 42A, 42B, 60#, 65#, 65Mn, 70#, 72A, 72B, 80#, 82A, 82B, 1006, 1008 ... ≤0.03≤0.03≤0.20≤0.20≤0.25SAE10450.450.200.56≤0.03≤0.03≤0.20≤0.20≤0.2542A 42B0.420.200.56≤0.03≤0.03≤0.20≤0 ... .20≤0.25SAE10600.600.200.56≤0.03≤0.03≤0.20≤0.20≤0.25SAE10650.650.200.56≤0.03≤0.03≤0.20≤0.20≤0 ...