Reheating the quenched steel to a certain temperature and then cooling it by a certain method is called tempering. Its purpose is to eliminate the internal stress caused by quenching, reduce the hardness and brittleness, in order to obtain the expected mechanical properties. There are three types of tempering: high temperature tempering, medium temperature tempering and low temperature tempering. Tempering is mostly used in conjunction with quenching and normalizing.
⑴ Quenching and tempering treatment: the heat treatment method of high temperature tempering after quenching is called quenching and tempering treatment. High temperature tempering refers to tempering between 500-650℃. Quenching and tempering can make the performance and material of steel be adjusted to a large extent, and its strength, plasticity and toughness are good, and it has good comprehensive mechanical properties.
⑵Aging treatment: In order to eliminate the size and shape changes of precision measuring tools or molds and parts during long-term use, the workpiece is often reheated to 100-150 after low temperature tempering (low temperature tempering temperature 150-250℃) before finishing. ℃, keep for 5-20 hours, this kind of treatment to stabilize the quality of precision parts is called aging. It is especially important to perform aging treatment on steel components under low temperature or dynamic load conditions to eliminate residual stress and stabilize steel structure and size.