Chemical composition
As follows (%): C: 0.32 ~ 0.42
Si: 0.8 ~ 1.2
Mn: <= 0.50
Cr: 4.50 ~ 5.50
Mo: 1.00 ~ 1.50
V: 0.8 ~ 1.2
S: <= 0.03
P: <= 0.03
Heat treatment
Air-cooled quenching, quenching temperature 1020 ~ 1050, hardness 56 ~ 58HRC, heat deformation small, surface nitriding nitriding process, the processing out of the product has better wear resistance.
Cryogenic treatment
In order to obtain the highest hardness and dimensional stability, immediately after quenching the mold in the deep cold -70 to -80 ℃, remain 3-4 hours, and then tempered by the cryogenic treatment of tool or mold hardness than conventional heat treatment hardness 1 -3HRC. Complex shape and size changes in the larger parts, cryogenic treatment has produced the risk of cracking