Common heat treatment process concepts

1. Normalizing: A heat treatment process that heats steel or steel components to an appropriate temperature above the critical point AC3 or ACM and maintains it for a certain period of time before cooling in air to obtain pearlite like structures.
2. Annealing: Heat the hypoeutectoid steel workpiece to 20-40 degrees above AC3, hold it for a period of time, and then slowly cool it in the furnace (or buried in sand or lime) to below 500 degrees and cool it in air
3. Solid solution heat treatment: Heat the alloy to a high-temperature single-phase zone and maintain a constant temperature to fully dissolve the excess phase into the solid solution, and then quickly cool to obtain a supersaturated solid solution heat treatment process
4. Aging: The phenomenon where the properties of an alloy change over time after solid solution heat treatment or cold plastic deformation, when placed at room temperature or slightly above room temperature.
5. Solid solution treatment: Fully dissolve various phases in the alloy, strengthen the solid solution, improve toughness and corrosion resistance, eliminate stress and soften, so as to continue processing and forming
6. Aging treatment: Heating and insulation at the temperature where the strengthening phase precipitates, allowing the strengthening phase precipitates to harden and improve strength
7. Quenching: A heat treatment process in which the steel is austenitized and cooled at an appropriate cooling rate, resulting in the transformation of unstable microstructures such as martensite within a certain range or all of the cross-section of the workpiece
8. Tempering: A heat treatment process that heats the quenched workpiece to an appropriate temperature below the critical point AC1 for a certain period of time, and then cools it using a satisfactory method to obtain the required structure and properties
9. Carbonitriding of steel: Carbonitriding is the process of simultaneously infiltrating carbon and nitrogen into the surface of the steel. Currently, medium temperature gas carbonitriding and low-temperature gas carbonitriding (i.e. 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 used for nitriding, with the main purpose of improving the wear resistance and bite resistance of steel.
10. Quenching and tempering: Generally, the heat treatment combining quenching and high-temperature tempering is called quenching and tempering. Tempering treatment is widely used in various important structural parts, especially 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 superior to those of normalized sorbite structure with 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 size of the workpiece, generally between HB200-350.
11. Brazing: A heat treatment process that uses brazing material to bond two types of workpieces together