Why do mechanical parts need heat treatment

Due to the large amount of impurities in the metal in the mining process, its physical and chemical properties have serious instability in use. Through heat treatment, it can be effectively purified and its internal purity can be improved. Heat treatment technology can also strengthen its quality improvement and optimize its actual performance. Heat treatment technology is a process in which the workpiece is heated in some medium and reaches a certain temperature.


As one of the most important processing processes in the material production process, metal heat treatment technology has great advantages compared with other common processing technologies. First of all, heat treatment only changes the internal microstructure or chemical composition of the surface of the workpiece, improves or enhances the performance of the workpiece, and generally does not change the overall chemical composition and shape of the workpiece. It is characterized by an improvement in the intrinsic quality of the workpiece, which is generally not visible to the naked eye.

The “four fires” in metal heat treatment refer to annealing, normalizing, quenching (solution) and tempering (aging). When the workpiece is heated and reaches a certain temperature, different holding times are used according to the size and material of the workpiece, and then slowly cooled, which is annealing. The main purpose of annealing is to appropriately reduce the hardness of the material, improve the plasticity of the material, facilitate subsequent processing, reduce the residual stress, and evenly distribute the composition and structure of the material. Machining is a processing technology that uses machine tool equipment to process parts. Corresponding heat treatment processes will be performed before and after machining parts. Its role is:


1. Remove the internal stress of the blank. Mostly used for castings, forgings, welded parts.

2. Improve processing conditions and make materials easy to process. Such as annealing, normalizing, etc.

3. Improve the comprehensive mechanical properties of metal materials. For example, conditioning treatment.

4. It can improve the hardness of the material. Such as, quenching, carburizing and quenching, etc.

Therefore, in addition to the reasonable selection of materials and various forming processes, the heat treatment process is often essential. Heat treatment generally does not change the shape and overall chemical composition of the workpiece, but imparts or improves the performance of the workpiece by changing the microstructure inside the workpiece or changing the chemical composition of the workpiece surface.


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Post time: Jul-15-2022