40Cr Steel Chemical Composition

40Cr steel?is a kind of Chinese GB standard alloy steel for engineering and machinery purpose, and one of the most widely used steel grades. For 40Cr material hardness, specifications and equivalent, please see the table below.

After quenching and tempering treatment, 40Cr steel has good comprehensive mechanical properties, low temperature impact toughness, low notch sensitivity, good hardenability, and high fatigue strength in cold oil. When water cooling, the complicated shape of the parts is prone to cracks, the cold bending plasticity is medium, and the cutting workability after normalizing is good, but the weldability is poor, should be preheated before welding, and is generally used in the state of quenching and tempering.

40Cr Steel Chemical Composition

Chemical Composition (%)
Grade C % Si Mn Cr
40Cr 0.37 C 0.44 0.17 C 0.37 0.5 C 0.8 0.80 C 1.10

Mechanical Properties of 40Cr Alloy Steel

  • Tensile strength: 810 N/mm2 (When actual hardness 25 HRC)
  • Yield strength: 785 N/mm2
  • Elongation after break: 9%
  • Rate of reduction in area: 45%
  • Impact absorbing energy: 47 J
  • Material Brinell hardness: 207 (annealing or high temperature tempering state)
  • Sample size: 25mm

Heat treatment specification

  • First quenching heating temperature: 850 C (Cooling: oil)
  • Tempering heating temperature: 520 C

Equivalent grades of 40Cr Material

40Cr steel equivalent to US ASTM AISI, European Germany DIN EN, British BS EN, France NF EN, Japanese JIS and ISO standard.

Equivalent (For reference)
China USA Germany Japan France UK ISO
Standard Grade Standard Grade Standard Grade (Steel number) Standard Grade Standard Grade Standard Grade Standard Grade
GB/T 3077 40Cr AISI or
ASTM A29/A29M
5140 DIN EN 10083-3 41Cr4 (1.7035) JIS G4104 SCr440 NF EN 10083-3 41Cr4 (1.7035) BS EN 10083-3