Metal heat treatment is one of the important technologies in mechanical manufacturing. Compared with other processing techniques, heat treatment usually does not change the shape of the workpiece and the overall chemical composition, but changes the internal microstructure of the workpiece or changes the chemical composition of the workpiece. Give or improve the use of the workpiece. Its characteristic is to improve the connotation quality of the workpiece. The first is to reduce the hardness of the metal material, improve the plasticity, to facilitate cutting or pressure processing, reduce residual stress, improve the arrangement and composition of the homogenization, or prepare for the post-heat treatment. Thorough Annealing and Isothermal Annealing Thorough Annealing, also known as recrystallization annealing, is often referred to as annealing. This type of annealing is primarily used for casting, forging and hot-rolled profiles of various carbon steels and alloy steels with sub-eutectoid compositions, sometimes for welding. structure.
It is often used as a heat treatment for some non-heavy workpieces or as a pre-heat treatment for some workpieces. In addition, there is a need for tempering. There are three main aspects of tempering:
1. Declining brittleness, eliminating or reducing internal stress, there is great internal stress and brittleness after quenching steel. If it is not tempered in time, it will cause deformation or even cracking of steel parts.
2. Obtain the mechanical function required by the workpiece. After the workpiece is quenched, the hardness is high and the brittleness is large. In order to satisfy the different functional requirements of various workpieces, the hardness can be adjusted by appropriate tempering to reduce the brittleness and obtain the demand. Patience, plasticity.
3. Stabilizing the size of the workpiece, in order to make the metal workpiece have the required mechanical, physical and chemical functions, in addition to the rational selection of materials and various forming techniques, heat treatment technology is usually essential.