牌号质量等级ABCSiMnP0.035S0.0350.0350.030.0250.020.0350.0350.0300.0250.0200.0350.0350.0300.0250.0200.0300.0250.0200.0300.0250.0200.0300.0250.0200.0300.0250.0200.0300.0250.020化学成分（质量分数）NbVTi不大≤0.20≤0.50≤1.70≤0.180.0350.030.030.0250.0350.035Q345CDEAB0.070.150.2Q390CDEAB≤0.20≤0.50≤1.700.0300.0300.0250.0350.035≤0.20≤0.50≤1.700.0300.0300.0250.030≤0.20≤0.60≤1.800.0300.0250.030≤0.18≤0.60≤1.800.0300.0250.030≤0.18≤0.60≤2.000.0300.0250.030≤0.18≤0.60≤2.000.0300.0250.030≤0.18≤0.60≤2.000.0300.0250.070.200.20Q420CDEC0.070.200.20Q460DEC0.110.200.20Q500DEC0.110.120.20Q550DEC0.110.120.20Q620DEC0.110.120.20Q690DE0.110.120.20分数）/%Cr不大于NiCuNMoBAlt不小于…0.30.50.30.0120.1…0.015..0.300.500.300.0150.10..0.015..0.800.800.300.0150.20..0.0150.300.800.550.0150.200.0040.0150.600.800.550.0150.200.0040.0150.800.800.800.0150.300.0040.0151.000.800.800.0150.300.0040.0151.000.800.800.0150.300.0040.015