A、B、C、D硫含量依次递减；A和B的磷含量相同，C的磷含量次之，D磷含量最少

Q235分A、B、C、D四级(GB/T 700-2006)

 Q235A级含C ≤0.22% Mn ≤1.4% Si ≤0.35% S ≤0.050 P ≤0.045

  Q235B级含C ≤0.20% Mn ≤1.4% Si ≤0.35% S ≤0.045 P ≤0.045

  Q235C级含C ≤0.17% Mn ≤1.4% Si ≤0.35% S ≤0.040 P ≤0.040

  Q235D级含C ≤0.17% Mn ≤1.4% Si ≤0.35% S ≤0.035 P ≤0.035