(1) Reduce brittleness, eliminate or reduce internal stress, there is a lot of internal stress and brittleness after quenching of steel parts, if not tempered in time, steel parts will deform or even crack.
(2) Obtain the required mechanical properties of the workpiece. After quenching, the workpiece has high hardness and brittleness. In order to meet the different performance requirements of various workpieces, the hardness can be adjusted through appropriate tempering to reduce the brittleness and obtain the required Toughness, plasticity.
(3) Stable workpiece size
(4) For some alloy steels that are difficult to soften during annealing, high temperature tempering is often used after quenching (or normalizing) to properly aggregate carbides in the steel and reduce hardness to facilitate cutting.
