化学成分:
(1) 40crmo c:0.35~0.45 si:0.15~0.40 mn:0.40~0.70 p:<=0.035 s:<=0.035 cr:1.00~1.50 mo:0.50~0.80
(2) 20crmo 碳 c :0.17~0.24 硅 si:0.17~0.37 锰 mn:0.40~0.70 硫 s :允许残余含量≤0.035 磷 p :允许残余含量≤0.035 铬 cr:0.80~1.10 镍 ni:允许残余含量≤0.030 铜 cu:允许残余含量≤0.030 钼 mo:0.15~0.25