Alloy structural steel: SCM440
Executive Standard: JIS G4053-2003
● Features and application:
Strength, high hardenability, toughness, and quenching of small deformation, high temperature strength and high creep rupture strength. Requirements for the manufacture of higher intensity than 35CrMo steel and larger cross-section of quenched and tempered forgings, such as the large locomotive traction gears, supercharger drive gear, rear axle, by the great link and spring load can also be used 2000m deep drill pipe joints and the following oil salvage tools.
● Chemical Composition:
Carbon C: 0.38 ~ 0.43
Si Si: 0.15 ~ 0.35
Manganese Mn: 0.60 ~ 0.90
Sulfur S: to allow the residual content ≤ 0.030
Phosphorus P: to allow the residual content ≤ 0.030
Chromium Cr: 0.90 ~ 1.20
Ni: to allow the residual content of ≤ 0.030
Copper Cu: to allow the residual content ≤ 0.030
Mo Mo: 0.15 ~ 0.30
● Mechanical Properties:
Tensile strength σb (MPa): ≥ 1080 (110)
Yield strength σs (MPa): ≥ 930 (95)
Elongation δ5 (%): ≥ 12
Reduction of area ψ (%): ≥ 45
Impact energy Akv (J): ≥ 63
Impact toughness αkv (J/cm2): ≥ 78 (8)
Hardness: ≤ 217HB
Sample size: Sample size is 25mm rough
● Heat treatment and microstructure specifications:
Standard heat treatment: quenching 850 ℃, oil cooling; tempering 560 ℃, water-cooled, oil-cooling.
Microstructure: Tempered sorbite.
● Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.