Heat resistant steel tooling castings used in heat treatment, the following basic knowledge sharing parts heat treatment:
7.cold treatment
Operation method: after quenching of steel parts, in the low temperature medium (such as dry ice and liquid nitrogen) cooled to 60 ~ 80 degrees or lower, take out after temperature uniform temperature to room temperature.
Objective: 1. Make harden steel residual austenite in all or most of the converted into martensite,so as to improve the hardness of steel, strength, abrasion resistance and fatigue limit; 2. Stable steel group, to stabilize the steel shapes and sizes.
Application key points: 1. The steel quenching should immediately after cold treatment, and then by the low temperature tempering, to eliminate the internal stress of the cryogenic cooling. 2. The cold treatment is mainly suitable for alloy steel close cutting tools, measuring tool and closely parts.