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 (%)|
|40Cr||0.37 – 0.44||0.17 – 0.37||0.5 – 0.8||0.80 – 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
- 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)|
|Standard||Grade||Standard||Grade||Standard||Grade (Steel number)||Standard||Grade||Standard||Grade||Standard||Grade||Standard||Grade|
|GB/T 3077||40Cr||AISI or|
|5140||DIN EN 10083-3||41Cr4 (1.7035)||JIS G4104||SCr440||NF EN 10083-3||41Cr4 (1.7035)||BS EN 10083-3||41Cr4 (1.7035)||ISO 683-1||41Cr4|
Applications of 40Cr material
After 40Cr alloy steel quenching and tempering treatment, it is used to manufacture medium-speed, medium-load parts
such as machine gears, shafts, worms, spline shafts, thimble
After quenching and tempering and high-frequency surface quenching,
it is used to manufacture high-hardness, wear-resistant parts such
as gears, shafts, spindles, crankshafts, sleeves, pins, connecting
rods, screws, nuts, intake valves, etc.
After quenching and medium temperature tempering, it is used to
manufacture heavy-duty, medium-speed impact parts such as oil pump
rotors, sliders, gears, spindles, collars, etc.
After quenching and low temperature tempering, it is used to
manufacture heavy-duty, low-impact, wear-resistant parts such as
worms, spindles, shafts and collars.
After carbonitriding treatment, it is used to manufacture
transmission parts with large size and high low temperature impact
toughness, such as shafts and gears.