Carbon C, 0.37 ~ 0.44 
 Silicon of Si 0.17 ~ 0.37 
 The manganese Mn0.50 ~ 0.80 
 Sulfur S allow the residual content of ≤ 0.025, 
 Phosphorus P to allow the residual content of ≤ 0.025, 
 Chromium Cr 0.60 ~ 0.90 
 Nickel of Ni 1.25 ~ 1.65 
 Copper Cu allow the residual content of ≤ 0.025, 
 Molybdenum Mo0.15 ~ 0.25.