What is 42CrMo4 Steel Bar

 

What is 42CrMo4 Steel Bar

42CrMo4 steel bar is an improved variety of American AISI standard 4140 steel. The steel has good machinability, easy polishing, biting and electroplating. It is suitable for manufacturing mechanical parts with high strength, high hardenability, good toughness, small deformation during quenching and high creep strength and endurance strength at high temperature. It can be used to manufacture forgings with higher strength and larger quenching and tempering section than 35CrMo steel, such as large gears for locomotive traction, supercharger transmission gears, rear axles, connecting rods and spring clamps with great load, and 42CrMo4 can also be used for drill pipe joints and fishing tools in deep oil wells below 2000m.

Chemical Composition of 42CrMo4:

• Carbon C: 0.38-0.45
• Silicon Si: 0.17-0.37
• Manganese Mn: 0.50-0.80
• Sulfur S: <0.035
• Phosphorus P: < 0.035
• Chromium Cr: 0.90-1.20
• Nickel Ni: Allowable Residual Content < 0.030
• Copper Co: Allowable Residual Content < 0.030
• Molybdenum Mo: 0.15-0.25

42CrMo4 Equivalent World Steel Grade:

• China GB 42CrMo,
• Russia OCT 38XM,
• USA AISI 4140/4142,
• UK BS 708M40/708A42/709M40,
• France NF 40CD4/42CD4,
• Germany DIN 41CrMo4/42CrMo4,
• Japan JIS SCM440

Mechanical properties of 42CrMo4:

• Density: 7.85x103kg/m3
• Tensile strength_b (MPa): > 1080 (110)
• Yield strength_s (MPa): > 930 (95)
• Section shrinkage(%): > 45
• Impact energy Akv (J): > 63
• Impact toughness value alpha kV (J/cm²): > 78 (8)
• Sample size: Sample blank size 25 mm

Heat treatment specification and metallographic structure:

Heat treatment specifications: quenching 850 C, oil-cooled; tempering 560 C, water-cooled, oil-cooled.

Metallographic structure: tempered sorbite.