Heat treatment method

1. Normalization: A heat treatment process in which steel or steel parts are heated to an appropriate temperature higher than the critical point AC3 or ACM for a certain time, and then cooled in air to obtain pearlitic structure. 2. Annealing: This is a heat treatment process. In this process, what we have to do is to do everything well. Solution heat treatment: the heat treatment process of heating the alloy to the high-temperature single-phase region and keeping the constant temperature, so that the excess phase is fully dissolved in the solid solution, and then rapidly cooling to obtain the supersaturated solid solution. 4. Aging: the phenomenon that the properties of the alloy change with time after solution heat treatment or cold plastic deformation when it is placed at room temperature or kept slightly higher than room temperature. 5. Solution treatment: fully dissolve all phases in the alloy, strengthen solution, improve toughness and corrosion resistance, relieve stress and soften, so as to continue processing and molding. 6. Aging treatment: heat and keep the temperature at which the strengthening phase precipitates, so as to precipitate and harden the strengthening phase and improve the strength. 7. Quenching: a heat treatment process in which the steel is austenitized and then cooled at a proper cooling rate, so that the unstable structures such as martensite of the workpiece change in all or a certain range of the cross section. Metallographic structure of 50CrVA spring steel quenched at 880℃. Tempering: a heat treatment process in which the quenched workpiece is heated to an appropriate temperature below the critical point AC 1 for a certain time, and then cooled in a satisfactory way to obtain the required structure and properties. 9. Carbonitriding of steel: Carbonitriding is the process of simultaneously infiltrating carbon and nitrogen into the steel surface. Traditionally, carbonitriding is also called cyanidation. At present, medium temperature gas carbonitriding and low temperature gas carbonitriding (gas soft nitriding) are widely used. The main purpose of medium temperature gas carbonitriding is to improve the hardness, wear resistance and fatigue strength of steel. Low temperature gas carbonitriding is mainly nitriding, the main purpose of which is to improve the wear resistance and bite resistance of steel. 10, ion nitriding In a nitriding atmosphere below one atmosphere, the process of nitriding by using the glow discharge generated between the workpiece (cathode) and the anode is called ion nitriding. Its characteristics are: fast nitriding speed; The structure is easy to control, and the brittleness of nitrogen layer is small; Small deformation; Easy to protect and save energy; Less pollution 1 1. Quenching and tempering: Usually, the heat treatment combining quenching and high temperature tempering is called quenching and tempering. Quenching and tempering treatment is widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts that work under alternating loads. Tempered sorbite structure is obtained after quenching and tempering, and its mechanical properties are better than normalized sorbite structure with the same hardness. Its hardness depends on the tempering temperature at high temperature, and is related to the tempering stability of steel and the cross-sectional size of workpiece, generally between HB 200 and 350. 12. Brazing: a heat treatment process that connects two kinds of workpieces with brazing filler metal. With the development of modern science and technology, heat treatment technology is more and more advanced, which brings greater convenience to industrial enterprises. Traditional heat treatment technology always needs to invest a lot of resources and raw materials to process high-quality metal workpieces, and it will also produce a lot of waste and underutilization of raw materials during the processing. However, in the process of ion nitriding heat treatment, the current ion nitriding furnace can save energy, emit less pollutants and gases and improve work efficiency. This is another important invention in the history of heat treatment.