A105化学成分C:≤0.35 Si:≤0.35 Mn:0.6-1.05 S:≤0.050 P:≤0.040,Cu≤0.4 Ni≤0.4 Mo≤0.12 V≤0.08 Cr≤0.3
Q345化学成分
Q345A:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.035,S≤0.035;
Q345B:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.035,S≤0.035;
Q345C:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.030,S≤0.030,Al≥0.015;
Q345D:C≤0.18,Mn ≤1.70,Si≤0.50,P≤0.030,S≤0.025,Al≥0.015;
Q345E:C≤0.18,Mn ≤1.70,Si≤0.50,P≤0.025,S≤0.020,Al≥0.015;
Q345A、B、C、D、E均含Nb≤0.07,V≤0.15,Ti≤0.20,Cr≤0.30,Ni≤0.012,Mo≤0.10。