20Cr Steel Grade

GB 20Cr alloy Steel is a high quality Quenched and Tempered Alloy Structural steel, It belong to the high quality low carbon,Low alloy chromium, molybdenum, nickel case hardening steel.

20Cr steel  has good comprehensive mechanical properties after quenching and low temperature tempering:
Good low temperature impact toughness and temper brittleness is not obvious. When carburizing, the grain of steel has a tendency to grow, so secondary quenching is required to improve the toughness of the core, and it is not suitable for cooling and quenching.
When the hardness after normalizing is 170-217 HB, the relative machinability is about 65%.

20Cr steel has good weldability, and generally does not require heat treatment after welding, but parts with a thickness greater than 15mm need to be preheated to 100-150 °C before welding, and tempering heat treatment may not be performed after welding.

Compared with 15Cr steel, 20Cr has higher strength and hardenability. The critical hardenable diameter in oil is 4-22mm, and the critical hardenable diameter in water is 11-40mm, but the toughness is poor.

The machinability is good under high temperature normalizing or quenching and tempering conditions, but it is poor after annealing.

20Cr alloy steel Chemical Composition:

Grade	C	Si	Mn	Cr	P ≤	S ≤	Cu ≤	Ni ≤	Mo ≤
20Cr	0.18 – 0.24	0.17 – 0.37	0.50- 0.80	0.70 – 1.00	0.030	0.030	0.030	0.030	0.030

20Cr alloy steel Mechanical Properties

Tensile strength	Yield strength	Elongation	Reduction of area	Poisson’s ratio	Impact absorbing energy
σb/MPa	σs/MPa	δ5(％)	ψ(％)		AKV/J
835	540	10 min	40 min	0.27-0.30	47 Min

Applications:
Machine gearbox gears, gear shafts, cams, worms, piston pins, dog clutches, etc.

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