Heat treatment knowledge

Quenching: refers to the heat treatment process of heating the steel to the quenching temperature (about 900 ℃, not more than 950 ℃), rapidly cooling after heat preservation, and transforming austenite into martensite.
The purpose of quenching is to obtain martensite structure and improve the hardness of steel.
Tempering: refers to the heat treatment process of heating the quenched steel to the tempering temperature (about 400 ℃) and cooling after heat preservation. With the increase of tempering temperature, the strength and hardness of steel decrease, and the plasticity and toughness increase.
The purpose of tempering is to eliminate quenching internal stress and prevent deformation or cracking; Quenched steel has high hardness and brittleness, and tempering can adjust hardness and toughness; Tempering can stabilize the workpiece size and prevent deformation during use