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.We are professional 40Cr Steel Bar manufacturer.
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 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.
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, hard chrome shaft, principal axis, crankshaft, arbor, inlet valve, bolt and etc.
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