The heat treatment process of high speed steel is relatively complex, which must go through a series of processes such as quenching and tempering. Quenching is generally carried out in two stages due to its poor thermal conductivity. First, preheat at 800~850 ℃ (to avoid causing large thermal stress), then rapidly heat to the quenching temperature of 1190~1290 ℃ (different brands have different temperatures in actual use), and then oil cooling, air cooling or gas filled cooling. Salt furnace is used for heating in the factory, and vacuum furnace is also widely used. After quenching, a part of retained austenite (about 30%) has not been transformed into martensite, which affects the properties of high-speed steel. In order to transform the residual austenite and further improve the hardness and wear resistance, it is generally necessary to carry out 2~3 times of tempering at 560 ℃, and each time of holding for 1 hour.
Production and manufacturing method: usually electric furnace is used for production, and powder metallurgy method was used to produce high-speed steel, so that the carbide is evenly distributed on the matrix as tiny particles, which improves the service life.
Application: It is used to manufacture various cutting tools. Such as turning tool, drill, hob, machine saw blade and mold with high requirements.
