q345圆钢7000一吨。 Q345圆钢含Mn,但含C低于45#圆钢 45#圆钢含C高于Q345圆钢,但不含MnQ345R---压力容器专用钢板(GB713) Q345A/B/C/D/E----低合金高强度钢(GB/T1591)化学成分 Q345A:C≤0.20,Mn ≤1.7,Si≤0.55,P≤0.045,S≤0.045,V 0.02~0.15; Q345B:C≤0.20, Mn ≤1.7,Si≤0.55,P≤0.040,S≤0.040,V 0.02~0.15; Q345C:C≤0.20,Mn ≤1.7,Si≤0.55,P≤0.035,S≤0.035,V 0.02~0.15,Al≥0.015; Q345D:C≤0.20...