Explanation

Using the principle of phase transformation of metal solid state and the principle of strengthening and toughening, different heating and cooling systems are used to change the structure of the white part of materials so as to improve and control its performance. Such a technical discipline is called heat treatment. To achieve the expected purpose. Heating and cooling systems must be selected to control the changes in the structure and properties of control materials, including heating rate, holding temperature, holding time, cooling rate, etc. This process system is called heat treatment process. The heat treatment process of metallic materials can be divided into: conventional heat treatment, such as annealing, normalizing, quenching, tempering, solution, aging, cryogenic treatment, etc; thermo-chemical treatment not only changes the structure and properties of the white part of materials, but also changes the chemical composition and structure of the surface layer, such as carburizing, nitriding, diffusion metallizing, etc; Thermomechanical treatment. deformation and phase are combined to enhance the treatment effect. Such as deformation quenching, deformation induced precipitation, etc; surface heat treatment mainly changes the structure and properties of the surface layer, such as high-frequency heat treatment, case hardening, surface laser heat treatment, etc. In order to ensure that no harmful changes (such as oxidation, decarburization, etc.) occur to the surface composition of steel product during heat treatment, controllable atmosphere, protective atmosphere or vacuum heat treatment are also widely used. In order to strengthen the heat treatment process and save energy, we also developed and applied heat treatment processes with high density energy, such as induction heating, ion bombardment, laser heating, and electron beam heating heat treatment, using the special work of non-equilibrium phase transformation.

Classification