What are the mechanical properties of 40Cr steel？

40Cr steel is the standard steel grade of GB in China, and 40Cr steel is one of the most widely used steels in mechanical manufacturing industry. After quenching and tempering, it has good comprehensive mechanical properties, good low temperature impact toughness and low notch sensitivity.

The hardenability of 40Cr steel is good. It can be quenched to Ф28 ~ 60mm in water quenching and to Ф15 ~ 40mm in oil quenching. In addition to quenching and tempering, the steel is also suitable for cyaniding and high frequency quenching. When the hardness is 174-229HB, the relative machinability is 60%. 40Cr steel is suitable for making medium-sized plastic mould.

The mechanical properties of 40Cr steel
Tempering heating temperature (℃): 520;
Tensile strength (σB / MPA): ≥810 (when the actual hardness is 25hrc)
Yield point (σs / MPA): ≥785
Elongation after fracture (δ5 /%): ≥9
Reduction of area (ψ/%): ≥45
Shock absorption energy (aku2 / J): ≥47
Brinell hardness (100/3000hbw) (annealed or tempered at high temperature): ≤207.