12Cr2Ni4A Material Name: Alloy structural steel grades: 12Cr2Ni4 Standard: GB / T 3077-1988 
 ● Features and Scope: high strength, good toughness, good hardenability, carburizing the surface layer hardness and good wear resistance, good cold plastic deformation, cutting is still good, but there are white spots sensitivity and tempering brittle, 
 Poor. Used for high load, alternating stress of working under a large carburized parts, such as by a variety of high load gear, worm gear, worm shaft and other mechanical parts. ● Chemical Composition: C: 0.10 ~ 0.16 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: 1.25 ~ 1.65 Ni-Ni: 3.25 ~ 3.65 Copper Cu: ≤ 0.030 to allow the residual content 
 ● Mechanical Properties: Tensile σb (MPa): ≥ 1080 (110) yield strength σs (MPa): ≥ 835 (85) Elongation δ5 (%): ≥ 10 Reduction of ψ (%): ≥ 50 impacts Power Akv (J): ≥ 71 impact toughness αkv (J/cm2): ≥ 88 (9) Hardness: ≤ 269HB sample size: the sample blank standard size 15mm ● Heat treatment and microstructure: heat treatment specifications: 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