GB/T 700-2006标准中碳素结构钢Q235按冶金质量分为A、B、C、D四个等级，各等级钢的化学成分为
Q235分A、B、C、D四级(GB/T 700-2006)
Q235A级含 C 0.14-0.22% Mn 0.30-0.65% Si ≤0.30% S ≤0.050 P ≤0.045
Q235B级含 C 0.12-0.20% Mn 0.30-0.70% Si ≤0.30% S ≤0.045 P ≤0.045
Q235C级含 C ≤0.18% Mn 0.35-0.80% Si ≤0.30% S ≤0.040 P ≤0.040
Q235D级含 C ≤0.17% Mn 0.35-0.80% Si ≤0.30% S ≤0.035 P ≤0.035
