Chemical composition: 
 Carbon the C: 0.28 ~ 0.35 Si Si: ≤ 0.80 Mn Mn: ≤ 1.00 sulfur S: ≤ 0.030 P: ≤ 0.035 Chromium Cr: 12.00 ~ 14.00 Ni - Ni: Allow containing ≤ 0.60 Molybdenum Mo: 0.50 ~ 1.00 
 Mechanical Properties: Hardness: Annealed ≤ 207HB; quenching and tempering, ≥ 50HV 
 Heat treatment and microstructure specifications: heat treatment specifications: 1) annealing, slow cooling of 800 ~ 900 ℃ or 750 ℃ ??rapid cooling; 2) quenching oil cooling, 1025 ~ 1075 ° C; 3) tempering, 200 ~ 300 ℃ oil, water , air-cooled. Microstructure: the organization is characterized by a martensitic.