西安Q345A方管:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.035,S≤0.035;
西安Q345B方管:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.035,S≤0.035;
西安Q345C方管:C≤0.20,Mn ≤1.70,Si≤0.50,P≤0.030,S≤0.030,Al≥0.015;
西安Q345D方管:C≤0.18,Mn ≤1.70,Si≤0.50,P≤0.030,S≤0.025,Al≥0.015;
西安Q345E方管:C≤0.18,Mn ≤1.70,Si≤0.50,P≤0.025,S≤0.020,Al≥0.015;
西安Q345A方管、B、C、D、E均含Nb≤0.07,V≤0.15,Ti≤0.20,Cr≤0.30,N≤0.012,Mo≤0.10。
西安20#方管、西安Q235B方管