9CrWMn steel chemical composition shown in Table 2-12-1. 



 Table 2-12-1 9CrWMn steel chemical composition (GB / T 1229-2000) w /% 

 C 
 Si 
 Mn 
 Cr 
 W 
 P 
 S 

 0.85 ~ 0.95 
 ≤ 0.40 
 0.90 ~ 1.20 
 0.50 ~ 0.80 
 0.50 ~ 0.80 
 ≤ 0.030 
 ≤ 0.030 


 Table 2-12-2 9CrWMn critical temperature of steel 



 Critical point 
 Ac1 
 Acm 
 Arl 
 Ms 

 Temperature (approximate) / ℃ 
 750 
 900 
 700 
 205