四级(GB/T 700-2006)Q235A级含 C ≤0.22% Mn≤1.4% Si ≤0.35% S ≤0.050 P ≤0.045Q235B级含 C≤0.20% Mn≤1.4% Si ≤0.35% S ≤0.045 P ≤0.045(经需方同意,碳含量可不大于0.22%)Q235C级含 C ≤0.17% Mn≤1.4% Si ≤0.35% S ≤0.040 P ≤0.040Q235D级含 C ≤0.17% Mn≤1.4% Si ≤0.35% S ≤0.035 P ≤0.035