20Cr2Ni4A 
 Material Name: Alloy structural steel grades: 20Cr2Ni4A 
 ● Features and Scope: 20Cr2Ni4A is high-quality alloy steel, high strength, toughness and good hardenability. Can not be directly carburized quenching, in order to reduce the surface retained austenite. Machinability and cold plastic deformation of the general. Poor welding, preheating before welding to be about 150 ℃, working hours white point sensitivity, a tendency to temper brittleness. 20Cr2Ni4A carburized parts for large cross-section, such as a large gear, shaft and require high strength, good toughness, conditioning parts. 
 ● Chemical Composition: C: 0.17 ~ 0.23 Si Si: 0.17 ~ 0.37 Manganese Mn: 0.30 ~ 0.60 S S: ≤ 0.03 Phosphorus P: ≤ 0.03 Chromium Cr: 1.25 ~ 1.65 Ni-Ni: 3.25 ~ 3.65 
 ● Mechanical Properties: Tensile σb (MPa): 1483 condition the yield strength σ0.2 (MPa): 1292 Elongation δ5 (%): 13 Shrinkage section ψ (%): 57 Toughness value αkv (J/cm2 ): 75 Hardness: 434HB sample size: a test specification and material microstructure ● Heat treatment: Heat treatment specification: 880 ℃ +780 ℃ oil quenching oil quenched, 200 ℃ tempered.