Chemical composition and mechanical properties of 20Cr2Ni4A, main use Relief Valve,Side Boiler Relief Valve,Cartridge Relief Valve,Pressure Safety Valve Jiangsu Hida Marine Valve Co., Ltd , https://www.haidavalve.com
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20Cr2Ni4A
Material Name: Alloy Structural Steel Grade: 20Cr2Ni4A
â—Features and scope of application:
20Cr2Ni4A is a high quality alloy steel with high strength, good toughness and hardenability. After carburizing, it cannot be directly quenched to reduce residual austenite in the surface layer. Machinability and cold deformation plasticity are general. The weldability is poor, and it needs to be preheated to about 150 °C before welding. The white point sensitivity is strong during working hours, and there is a tendency to temper brittleness. 20Cr2Ni4A is used for large-section carburizing parts, such as large gears, shafts, and quenched and tempered parts with high strength and toughness.
â—Chemical composition:
Carbon C: 0.17~0.23
Silicon Si: 0.17~0.37
Manganese Mn: 0.30 to 0.60
Sulfur S: ≤0.03
Phosphorus P :≤0.03
Chromium Cr: 1.25 ~ 1.65
Nickel Ni: 3.25～3.65
â—Mechanical properties:
Tensile strength σb (MPa): 1483
Conditional yield strength σ0.2 (MPa): 1292
Elongation δ5 (%): 13
Area shrinkage ψ (%): 57
Impact toughness value αkv (J/cm2): 75
Hardness: 434HB
Specimen size: a sample â— heat treatment specifications and metallographic organization:
Heat treatment specification: 880 ° C oil quenching + 780 ° C oil quenching, 200 ° C tempering. 
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Chemical composition and mechanical properties of 20Cr2Ni4A