Several commonly used heat treatment methods

Heat treatment can be seen everywhere in the industrial field. It is a necessary processing technology for metal parts such as automobile and aeronautical parts. It is to ensure that the metal parts after processing are more heat-resistant, plastic and hard, thus prolonging the service life of the products. Heat treatment is a metal thermal processing technology, which is used to heat, heat and cool metal materials in a certain medium, and to control the properties of the material by changing the surface of the material or the microstructure of the internal metallographic structure. Several commonly used heat treatment methods are introduced below.
1. normalizing: heating the steel or steel to a proper temperature of AC3 or ACM above the critical point for a certain time and cooling in the air after a certain period of time, the heat treatment process of pearlite like tissue is obtained.
Annealed 2. annealing: heat the subeutectoid steel workpiece to 20 - 40 degrees above AC3, after a period of heat preservation, cooling with the furnace slowly (or buried in sand or lime) to less than 500 degrees in the air.
3. solid solution heat treatment: heating the alloy to the constant temperature of the high temperature single-phase region, so that the excess phase is fully dissolved into the solid solution, and then quickly cooled to get the heat treatment process of the supersaturated solid solution.
4. aging: when the alloy is subjected to solid solution heat treatment or cold plastic deformation, its properties change with time at room temperature or slightly above room temperature.
5. solid solution treatment: make all phases of the alloy fully dissolved, strengthen the solid solution and improve the toughness and corrosion resistance, eliminate stress and softening, so as to continue processing.
6. aging treatment: heating and holding at the temperature of the precipitated phase, so that the precipitates can be precipitated and hardened, and the strength will be increased.
Quenching 7.: cooling the steel austenitizing with appropriate cooling rate to make the workpiece in the cross section of the whole or a certain range of martensite and other unstable structural transformation of the heat treatment process. Microstructure of 50CrVA spring steel quenched at 880 C
8. tempering: the quenched workpiece is heated to a proper temperature below the critical point AC1 for a certain period of time and then cooled in a required way to obtain the desired tissue and performance heat treatment process.
Carbonitriding of 9. steel: carbonitriding is the process of simultaneous infiltration of carbon and nitrogen into the surface of the steel. Traditionally, carbonitriding is also known as cyanidation. Currently, mesophilic gas carbonitriding and low temperature gas nitrocarburizing (gas nitriding) are widely used. The main purpose of mesophilic gas carbonitriding is to improve the hardness, wear resistance and fatigue strength of steel. Low temperature gas nitrocarburizing is mainly nitriding, and its main purpose is to improve the wear resistance and bite resistance of steel.
10, ion nitriding in a nitriding atmosphere below a atmospheric pressure, the process of nitriding by the glow discharge produced between the cathode and the anode is called ion nitriding. Its characteristics are: nitriding speed is fast, organization is easy to control, nitrogen layer brittleness is small, deformation is small, easy to protect, save energy, less pollution.
11. quenching and tempering treatment (quenchingandtempering): heat treatment combined with quenching and tempering is commonly used as quenching and tempering. Quenching and tempering treatment is widely used in all kinds of important structural parts, especially those connecting rods, bolts, gears and shafts under alternating load. After tempering and tempering, the microstructure of tempered Soxhlet is obtained, and its mechanical properties are superior to those of normalizing suxhnite 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 section size of workpieces, generally between HB200 - 350.
12. brazing: the heat treatment process of bonding two parts together with solder. With the development of modern science and technology and the increasing development of heat treatment technology, the industrial enterprises have also brought more convenience, and the traditional hot processing technology always needs to invest a lot of resources and raw materials to process high quality metal workpiece, and there will be a lot of waste in the process. In the process of ion nitriding heat treatment process, the ion nitriding furnace can save energy, discharge pollutants and gases less, and improve the efficiency of the current ion nitriding furnace. It is one of the most important inventions in the history of heat treatment.