Chemical composition and mechanical properties of 18Cr2Ni4WA, main use Relief Valve,Side Boiler Relief Valve,Cartridge Relief Valve,Pressure Safety Valve Jiangsu Hida Marine Valve Co., Ltd , https://www.haidavalve.com
Http://news.chinawj.com.cn Material Name: Alloy Structural Steel Grade: 18Cr2Ni4WA
Standard: GB/T 3077-1999
18Cr2Ni4WA is a high strength medium alloy carburized steel. To make the C and austenite content not exceed the standard, it can be carburized at 900~920 °C after carburizing, 600~650 tempering, deep cooling treatment, the hardness after oil quenching is about 48, want to reach HRC58- 63, surface carburization must be carried out.
18Cr2Ni4WA steel commonly used alloy carburized steel, high strength, high toughness, good hardenability, can also be used without carburizing and quenching and tempering, generally used for larger cross section, high load and good toughness, low notch sensitivity Important parts.
â—Chemical composition:
18Cr2Ni4WA alloy structural steel Carbon C: 0.13～0.19
Silicon Si: 0.17~0.37
Manganese Mn: 0.30 to 0.60
Sulfur S: Allowable residual content ≤0.025
Phosphorus P: Allowable residual content ≤0.025
Chromium Cr: 1.35~1.65
Nickel Ni: 4.00 to 4.50
Copper Cu: Allowable residual content ≤0.025
Tungsten W: 0.80~1.20
â—Mechanical properties:
Tensile strength σb (MPa): ≥1175 (120)
Yield strength σs (MPa): ≥1029 (105)
Elongation δ5 (%): ≥10
Area shrinkage ψ (%): ≥ 45
Impact work Akv (J): ≥78
Impact toughness value αkv (J/cm2): ≥ 98 (10)
Hardness: ≤ 269HB
Sample size: sample blank size is 15mm
â— Heat treatment specifications and metallographic organization:
Heat treatment specification: quenching: first 950 ° C, second 850 ° C, air cooling; tempering 200 ° C, water cooling, air cooling.
â— Delivery status: Delivery by heat treatment (normalizing, annealing or high temperature tempering) or no heat treatment, the delivery status should be stated in the contract. 
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