Work Location Arrangement For Heat Treatment of Workpieces

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The processing of the parts is carried out along a certain process route, and the reasonable arrangement of the position of the heat treatment process is of great significance to ensure the quality of the parts and improve the cutting performance. According to the purpose of heat treatment and the location of the process, heat treatment can be divided into two categories: preliminary heat treatment and final heat treatment. The general rules for the location of the two processes are as follows:

1. Preparatory Heat Treatment

Preliminary heat treatment includes annealing, normalizing, quenching and tempering, etc. The annealing process position is usually arranged after the blank is produced and before the cutting process, in order to eliminate the internal stress of the blank, uniform the structure, improve the machinability, and prepare the organization for the subsequent heat treatment For precision parts, in order to eliminate the residual stress of machining, stress relief annealing should be arranged after semi-finishing. The quenching and tempering process is generally arranged after rough machining, before finishing or semi-finishing, in order to obtain good comprehensive mechanical properties and prepare for the subsequent heat treatment.

2. Final Heat Treatment

The final heat treatment includes quenching, tempering and surface heat treatment, etc. After this kind of heat treatment, the parts can obtain the required performance. However, due to the high hardness of the final heat-treated parts, it is not suitable for other forms of cutting except for grinding. Therefore, the final heat treatment process position is generally arranged after semi-finishing.

Some parts have low performance requirements. Annealing, normalizing or quenching and tempering can meet the requirements when the blanks are processed. At this time, annealing, normalizing and quenching and tempering can also be used as the final heat treatment.

The following analysis takes machine tool gears and automobile gears as examples:

The speed adjustment and function transmission in machine tools and automobiles mainly rely on gears. Therefore, gears are very important and used parts in machine tools and automobiles.

The general force conditions of gears are as follows:

(1) The gear bears great alternating bending stress.

(2) Withstand the impact force when shifting, starting or when the meshing is uneven.

(3) The tooth surfaces roll and slide with each other, and bear the contact pressure stress.

Therefore, the main forms of gear damage are tooth fracture, tooth surface peeling and excessive wear. Therefore, the gear material is required to have the following main properties:

(1) High bending fatigue strength and contact fatigue strength.

(2) The tooth surface has high hardness and wear resistance.

(3) The gear core has sufficient strength and toughness.

In addition, better heat treatment processability is required, such as small deformation and a certain law of deformation.

Learn more:

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