化学成分要求:
C: ≤0.24
Si: ≤0.45
Mn: ≤1.40
P: ≤0.025
S: ≤0.015
V: ≤0.10
Nb: ≤0.05
Ti: ≤0.04
Cu: ≤0.50
Ni: ≤0.30
Cr: ≤0.30
Mo: ≤0.15
V+Nb+Ti: ≤0.15
* 碳含量每降低0.01%,锰含量可增加0.05%,z大至1.65%。
* 不允许有意添加硼,残余B≤0.001%