Several common heat treatment concepts:
1. Normalizing: The heat treatment process of heating steel or steel parts to an appropriate temperature above the critical point AC3 or ACM for a certain period of time and then cooling in the air to obtain a pearlite-like structure.
2. Annealing: heat the hypoeutectoid steel workpiece to 20-40 degrees above AC3, after holding for a period of time, slowly cool with the furnace (or bury it in sand or lime) to below 500 degrees and cool in the air. Craft
3. Solution heat treatment: heat the alloy to a high-temperature single-phase zone to maintain a constant temperature, so that the excess phase is fully dissolved into the solid solution, and then rapidly cooled to obtain a supersaturated solid solution.
4. Aging: After solution heat treatment or cold plastic deformation, the performance of alloy changes with time when it is placed at room temperature or kept slightly higher than room temperature.
5. Solid solution treatment: fully dissolve various phases in the alloy, strengthen solid solution and improve toughness and corrosion resistance, eliminate stress and soften, so as to continue processing and forming
6. Aging treatment: heat and keep warm at the temperature at which the strengthening phase precipitates, so that the strengthening phase precipitates out, hardened and improved strength
7. Quenching: A heat treatment process in which the steel is austenitized and cooled at an appropriate cooling rate to cause the workpiece to undergo martensite and other unstable structural transformations in the cross section or within a certain range
8. Tempering: heat the quenched workpiece to an appropriate temperature below the critical point AC1 for a certain period of time, and then cool it with a method that meets the requirements to obtain the required structure and performance of the heat treatment process
9. Carbonitriding of steel: Carbonitriding is the process of simultaneously infiltrating carbon and nitrogen into the surface of steel. Conventionally, carbonitriding is also called cyanidation. At present, medium temperature gas carbonitriding and low temperature gas carbonitriding (ie, gas nitrocarburizing) 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, and its main purpose is to improve the wear resistance and seizure resistance of steel.
10. Quenching and tempering: It is generally customary to combine the heat treatment of quenching and high temperature tempering as 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. After quenching and tempering, the tempered sorbite structure is obtained, and its mechanical properties are better than the normalized sorbite structure of the same hardness. Its hardness depends on the high-temperature tempering temperature and is related to the tempering stability of the steel and the size of the workpiece section, generally between HB200-350.
11. Brazing: a heat treatment process for bonding two workpieces together with brazing filler metal