Material Name: Alloy structural steel
Grade: 20Cr2Ni4A
● Features and Scope:
Is a high-quality alloy steel, high strength, good toughness and hardenability. Not directly after carburizing quenching, in order to reduce the surface residual austenite. Machinability and cold plastic deformation in general. Poor welding, preheating before welding to about 150 ℃, the strong sensitivity of the white point of working hours, there is a tendency to temper brittleness. Carburizing parts for large cross-section, such as high-large gears, shafts and require strength, toughness, good tempered parts.
● Chemical Composition:
Carbon C: 0.17 ~ 0.23
Si Si: 0.17 ~ 0.37
Mn Mn: 0.30 ~ 0.60
Sulfur S: ≤0.03
Phosphorus P: ≤0.03
Chromium Cr: 1.25 ~ 1.65
Ni Ni: 3.25 ~ 3.65
● Mechanical Properties:
Tensile strength σb (MPa): 1483
Conditions yield strength σ0.2 (MPa): 1292
Elongation δ5 (%): 13
Reduction of ψ (%): 57
Impact toughness αkv (J / cm2): 75
Hardness: 434HB
Sample size: a sample
● Heat treatment and microstructure specifications:
Heat treatment specifications: 880 ℃ oil quenching + 780 ℃ oil quenching, 200 ℃ tempering.