Introduction
42CrMo steel is a Chinese alloy steel, and has high strength and toughness, good hardenability, and no obvious temper brittleness. After quenching and tempering treatment, it has high fatigue limit and resistance to multiple impacts, and good low temperature impact toughness.

Applications
42CrMo alloy steel generally used for engineering steel purpose, and for making important parts requiring higher strength and larger size of the quenched section than 35CrMo steel, such as shafts, crankshafts, large gears for locomotive traction, supercharger gears, gearbox gears, engine cylinders, oil drill pipe joints, large load rods and spring clips.

Datasheet
42CrMo Steel Chemical Composition
Chemical Composition %
Steel Grade C Si Mn P S Cr Mo
42CrMo 0.38 to 0.45 0.17 to 0.37 0.50 to 0.80 ≤ 0.030 ≤ 0.030 0.90 to 1.20 0.15 to 0.25
42CrMo Alloy Steel Mechanical Properties
Yield strength: ≥ 930 MPa
Tensile strength: ≥ 1080 MPa
Elongation: ≥12%
Rate of reduction in area: ≥45%
Impact absorbing energy: ≥ 63 J
Material Brinell hardness: ≤229 (Annealed or high temperature tempered steel rod)
Sample diameter: 25mm
Heat treatment specification
First quenching heating temperature: 850 °C (Cooling – oil)
Tempering heating temperature: 560 °C (Cooling – water, oil)
Equivalent
42CrMo steel equivalent to US AISI ASTM, European EN (Germany DIN EN, UK BSI EN, France NF EN, Japan JIS, and ISO standard.

China USA Germany UK Japan France ISO
Standard Grade Standard Grade Standard Grade (Steel number) Standard Grade (Steel number) Standard Grade Standard Grade (Steel number) Standard Grade
GB/T 3077 42CrMo SAE, AISI;
ASTM A29/A29M AISI 4140 steel DIN EN 10083-3 42CrMo4 (1.7225) BS EN 10083-3 42CrMo4 (1.7225) JIS G4105 SCM440 NF EN10083-3 42CrMo4 (1.7225) ISO 683-17