Supply state and the hardness of annealed hardness <235HBS. 

 Chemical composition: 

 C: 0.39 

 SI: 0.90 

 MN: 040 

 CR: 5.30 

 Of MO: 1.20 

 V: 0.80 

 P: 0.015 

 S: 0.002 

 CU: 0.10 

 NI: 0.10 

 The annealing specification temperature of 820 ~ 870 ° C, slow cooling and annealing hardness <235HBS. 

 Quenching and tempering, regulating the quenching temperature of 1000 ~ 1050 ° C air-cooled; tempering temperature of 550 ~ 650 ° C, air-cooled; quenching, tempering hardness of 55HRC.