40Cr Alloy Steel
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.
Datasheet & Specification
The tables below list 40Cr alloy steel datasheet and specification including chemical composition, properties and heat treatment, etc.
40Cr Steel Chemical Composition
Chemical Composition (%) Grade C % Si Mn Cr 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 tempering state)
- Sample size: 25mm
Heat treatment specification
- First quenching heating temperature: 850 °C (Cooling: oil)
- Tempering heating temperature: 520 °C
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 sleeves, etc.
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.
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/A29M5140 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
If you need product information or price, please fill in your contact information in the form below, we will usually contact you within 12 hours. You could also email me info@lyapm.com to get prompt reply.40Cr steel material widely be used in the machine-building industry. 40Cr is a standard grade of GB. After quenching and tempering, it will get great comprehensive mechanical property and great low-temperature impact toughness. And its hardenability is good. After the oil quenching, the fatigue limit will be higher. But the fittings with complex shape is easy to get crack after the water quenching. It is also suitable for cyaniding and high-frequency quenching beside Q+T. Its machinability also is good, if the hardness is 174-229 HB, the machinability is 60%. 40Cr steel material is a good choice for medium type plastic mold. It belongs to mild Q+T steel and cold heading mold steel. Also, the price is not high, easy to be processed. After the right heat treatment, it will get good toughness, plasticity and wear resistance. Tempering at the range of 550-570℃, it will get the best mechanical property. The equivalent steel grade of 40Cr is 40MnB, 45 MnB, 35SiMn, 42SiMn, 40MnVB, 42MnV, 40MnMoB, 40MnWB and etc.
40Cr Steel Material Chemical Composition
Grade C(%) Si(%) Mn(%) Cr(%) P(%) S(%) Cu(%) Ni(%) Mo 40Cr 0.37-0.44 0.17-0.37 0.50-0.80 0.80-1.10 MAX 0.035 MAX 0.035 MAX 0.30 MAX 0.30 MAX 0.15
40Cr Mechanical Properties
- Tensile Strength: ≥ 810 MPa
- Yield Point: ≥ 785 MPa
- Impact Absorbing Energy: ≥ 47 J
What is 40Cr Steel Material Used for?
It is one of the most popular steel grades in the industry. After Q+T heat treatment, it usually is used to make parts. Such as the gears of machine tools, shaft, worm, spline shaft and etc. If it is through quenching and tempering; high-frequency quenching, it will be good choice for fittings with high hardness and wear resistance. For example, wheel gear, shaft, principal axis, crankshaft, arbor, inlet valve, bolt and etc.
Q+T Hardness
After quenching and tempering, the hardness of 40Cr is in the range of 32-36HRC, which means about 301-340 HB.
- 830℃-860℃ oil quenching: 55HRC
- 150℃ tempering: 55HRC
- 200℃ tempering: 53HRC
- 300℃ tempering: 51HRC
- 400℃ tempering: 43HRC
- 500℃ tempering: 34HRC
- 550℃ tempering: 32HRC
- 600℃ tempering: 28HRC
- 650℃ tempering: 24HRC
- 700℃ tempering: 20HRC
40Cr Steel vs 45# Steel
The carbon content of 40Cr is lower than 45# steel. At the condition of hot-rolled, their mechanical property is almost the same. But the price of 40Cr is higher than 45# steel about a half. So if your budget is not high, you maybe need to choose the 45# steel.
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