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.

40Cr steel 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.

40Cr Steel Chemical Composition:

Grade	C %	Si	Mn	Cr
40Cr	0.37 – 0.44	0.17 – 0.37	0.5 – 0.8	0.80 – 1.10

40Cr Steel Mechanical Properties

Tensile	Yield	Bulk modulus	Shear modulus	Poisson’s ratio	Izod Impact
KSI	KSI	KSI	KSI		ft.lb
76900	55800	20300	11600	0.27-0.30	84.8

Applications:
GB 40CR steel is widely used for a variety of applications in the used in the automotive and engineering industries for toolholders and other such components. Typical applications such as valve bodies, pumps and fittings, Shaft, the high load of wheel, bolts, double-headed bolts, gears, etc

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