Common heat treatment processes include normalizing, annealing, solid solution, aging, quenching, tempering, annealing, carburizing, nitriding, quenching, spheroidizing, brazing, etc.:

1. Normalizing: The steel or steel is heated to a suitable temperature above the critical point AC3 or ACM for a certain period of time and then cooled in the air to obtain a heat treatment process of the pearlite-like structure.

2. Annealing: A heat treatment process in which the sub-eutectoid steel workpiece is heated to a temperature of 20-40 degrees above AC3 for a period of time after cooling for a period of time, with the furnace slowly cooling (or buried in sand or lime) to below 500 degrees in air.

3. Solution heat treatment: the alloy is heated to a high temperature single-phase zone constant temperature maintenance, the excess phase is fully dissolved into the solid solution, and then rapidly cooled to obtain a heat treatment process of the supersaturated solid solution.

4. Aging: The phenomenon that the properties of a alloy change with time after being subjected to solution heat treatment or cold plastic deformation at room temperature or slightly above room temperature.

5. Solution treatment: fully dissolves various phases in the alloy, strengthens the solid solution and improves toughness and corrosion resistance, eliminating stress and softening, so as to continue processing.

6. Aging treatment: heating and keeping warm at the temperature of strengthening the phase, allowing the strengthening phase to precipitate and harden and increase the strength.

7. Quenching: A heat treatment process in which the steel is austenitized and cooled at an appropriate cooling rate to cause a structural transformation of unstable microstructure such as martensite in all or a certain range of the cross section.

8. Tempering: The quenched workpiece is heated to a suitable temperature below the critical point AC1 for a certain period of time and then cooled by a satisfactory method to obtain the desired heat treatment process for the structure and properties.

9. Carbonitriding of steel: Carbonitriding is the process of simultaneously infiltrating carbon and nitrogen into the surface of steel. It is customary for carbonitriding, also known as cyanidation, to be widely used in medium temperature gas carbonitriding and low temperature gas carbonitriding (ie, gas nitrocarburizing). The main purpose of carbon monoxide in medium temperature gas is to increase the hardness, wear resistance and fatigue strength of steel. The 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: The heat treatment that combines quenching with high temperature and tempering is called quenching and tempering. Quenching and tempering is widely used in a variety of important structural parts, especially those that work under alternating loads, such as connecting rods, bolts, gears and shafts. After quenching and tempering treatment, the tempered sorbite structure is obtained, and its mechanical properties are superior to the normal-fired 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 cross-sectional dimensions of the workpiece, generally between HB200 and 350.

11. Brazing: A heat treatment process in which two workpieces are heated and melted together by a solder.