12CrNi3A 

 Military Steel: 12CrNi3A Standard: GB / T 3077-1988 
 12CrNi3A alloy steel are hardened steel, steel has a higher than 12CrNi2A hardenability, therefore, can be used in the manufacture of steel cross-section slightly larger than 12CrNi2A parts. Or quenching and tempering the steel after high temperature tempering has good mechanical properties, good low temperature toughness of steel, notch sensitivity is small, good cutting performance, when the hardness of HB260 ~ 320, the relative machinability of 60% ~ 70%. In addition, the low hardness of annealed steel, plastic, therefore, both can be used to manufacture cutting dies, cold extrusion can also be used to manufacture molds. To improve the wear resistance of the mold cavity, the mold after molding the need for carburizing treatment, and then quenching and tempering, in order to ensure the mold surface with high hardness, high wear resistance and heart Ministry has good toughness, the steel suitable for manufacturing large and medium-sized plastic mold. However, the tendency to temper brittleness of steel and the formation of a white point of orientation. 
 Chemical Composition: 
 Carbon C: 0.10 ~ 0.17 

 Si Si: 0.17 ~ 0.37 Manganese Mn: 0.30 ~ 0.60 S S: to allow the residual phosphorus content ≤ 0.035 P: ≤ 0.035 to allow the residual content of chromium Cr: 0.60 ~ 0.90 Ni-Ni: 2.75 ~ * Copper Cu: ≤ 0.030 to allow the residual content 
 Mechanical Properties 
 Tensile strength σb (MPa): ≥ 930 (95) yield strength σs (MPa): ≥ 685 (70) Elongation δ5 (%): ≥ 11 Reduction of ψ (%): ≥ 50 Impact energy Akv (J ): ≥ 71 impact toughness αkv (J/cm2): ≥ 88 (9) Hardness: ≤ 217HB sample size: Sample size is 15mm blank 
 Heat treatment 
 Standard heat treatment: quenching: the first 860 ℃, the second 780 ℃, oil-cooling; tempering 200 ℃, water, air-cooled. ● Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract. ● processing performance: When the hardness of HB260 ~ 320, the relative machinability of 60% to 70%