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

1. Normalizing: a heat treatment process in which steel or steel parts are heated to a critical point AC3 or above an appropriate temperature for a certain period of time and then cooled in the air to obtain pearlitic tissue.

2. 1. A heat treatment process in which a subeutectoid steel workpiece is heated to 20 -- 40 degrees above AC3, held for a period of time, and then cooled in the air as the furnace slowly cools (or is cooled in sand or lime) to below 500 degrees.

3. Soluble solution heat treatment: the alloy is heated to high temperature single-phase constant temperature maintenance, so that the excess phase fully dissolved into the solid solution, and then rapid cooling, in order to obtain the heat treatment process of supersaturated solid solution.

4. Aging: The phenomenon that the properties of an alloy after solution heat treatment or cold plastic deformation change with time when it is kept at or slightly above room temperature.

5. Solid solution treatment: make all kinds of phases in the alloy fully dissolved, strengthen the solid solution and improve toughness and corrosion resistance, eliminate stress and softening, so as to continue processing and forming.

6. Aging treatment: heating and holding at the temperature at which the hardening phase precipitates, so that the hardening phase precipitates, hardening and improving strength.

7. Quenching: a heat treatment process in which the austenitized steel is cooled at an appropriate cooling rate so that the unstable structure transformation such as martensite occurs in the cross section or within a certain range of the workpiece.

8. Tempering: A heat treatment process in which a quenched workpiece is heated to an appropriate temperature below the critical point AC1 for a specified period of time, followed by cooling in a specified manner in order to obtain the desired structure and properties.

9. Carbonitriding of steel: Carbonitriding is the simultaneous infiltration of carbon and nitrogen into the surface of steel. Carbonitriding, also known as cyanidation, is widely used in medium temperature gas carbonitriding and low temperature gas carbonitriding (i.e. gas soft nitriding). The main purpose of gas carbonitriding at medium temperature is to improve the hardness, wear resistance and fatigue strength of steel. The main purpose of low temperature gas carbonitriding is to improve the wear resistance and bite resistance of steel.

10. Quenching and tempering treatment: the heat treatment combining quenching and high temperature tempering is commonly called quenching and tempering treatment. The quenching and tempering treatment is widely used in all kinds of important structural parts, especially those connecting rods, bolts, gears and shafts which work under alternating loads. After tempering and tempering, the mechanical properties of tempered sortenite are better than those of normalized sortenite 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 the workpiece, generally between HB200 and 350.

11. Brazing: A heat treatment process in which two kinds of work pieces are heated and fused together with a filler metal.