一、结构钢牌号及化学成分 1、普通碳素结构钢牌号及化学成分： C Si Mn P S Q1950.06～0.120.12～0.300.25～0.50≤0.045≤0.050Q215A0.09～0.150.12～0.300.25～0.55≤0.045≤0.050Q315B0.09～0.150.12～0.300.25～0.55≤0.045≤0.045Q235A0.14～0.220.12～0.300.30～0.65≤0.045≤0.050Q335B0.12～0.200.12～0.300.30～0.70≤0.045≤0.045Q235C≤0.180.12～0.300.35～0.80≤0.040≤0.040Q235D≤0.170.12～0.300.35～0.80≤0.030≤0.030Q255A0.18～0.280.12～0.300.40～0.70≤0.045≤0.050Q255B0.18～0.280.12～0.300.40～0.70≤0.045≤0.045Q2750.28～0.380.15～0.350.5～0.80 ≤0.045≤0.050
