42CrMo alloy steel

42CrMo steel belongs to alloy structural steel in terms of material classification.

42CrMo steel is an ultra-high strength steel with high strength and toughness, good hardenability, no obvious temper brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low temperature impact toughness.

42CrMo Chinese executive standard GB/T 3077-1999
Its corresponding International Standards Organization grade: 42CrMo4
Corresponding Japanese brand: SCM440
Corresponding German grade: 42CrMo4 or 1.7225
Approximately corresponding to the US grade: 4140 or G41400

42CrMo steel chemical composition:
Carbon C: 0.38～0.45%
Silicon Si: 0.17～0.37%
Manganese Mn: 0.50～0.80%
Sulfur S: allowable residual content ≤ 0.035%
Phosphorus P: allowable residual content ≤ 0.035%
Chromium Cr: 0.90～1.20%
Nickel Ni: allowable residual content ≤ 0.30%
Copper Cu: allowable residual content ≤ 0.30%
42CrMo steel
42CrMo steel
Molybdenum Mo: 0.15～0.25%

42CrMo mechanical properties:
Hardness: Annealed, 147~241HB, 42CrMo
42CrMo mechanical properties:
Tensile strength σb (MPa): ≥1080(110)
Yield strength σs (MPa): ≥930(95)
Elongation δ5 (%): ≥12
Area shrinkage ψ (%): ≥45
Impact energy Akv (J): ≥63
Impact toughness value αkv (J/cm2): ≥78(8)
Hardness: ≤217HB

42CrMo characteristics and scope of application:
High strength, hardenability, good toughness, small deformation during quenching, high creep strength and lasting strength at high temperature.
It is used to manufacture forgings that require higher strength and larger quenched and tempered section than 35CrMo steel, such as large gears for locomotive traction, supercharger transmission gears, pressure vessel gears, rear axles, connecting rods and spring clips that are heavily loaded , can also be used for drill pipe joints and fishing tools in oil wells below 2000m, and can be used for molds of bending machines, etc.

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