Basic Principles of Heat Treatment Process

Heating

The first step in heat treatment is to heat the metal material to a specific temperature. The heating temperature depends on the composition of the material and the desired property changes. During the heating process, the grain structure inside the material begins to become unstable, and atoms begin to migrate, causing the grain interface to disappear, thus creating conditions for subsequent structural changes.

Insulation

Once the target temperature is reached, the metal material needs to be kept at that temperature for a period of time to ensure uniform temperature distribution and promote the redistribution of grains and the occurrence of phase changes. The holding time depends on the type and thickness of the material and usually ranges from a few minutes to a few hours.

Cool Down

After the heat preservation is completed, the metal material needs to be cooled to room temperature at a specific rate. The cooling rate controls the final microstructure and has a significant impact on the material's hardness, toughness and other performance parameters. Different cooling rates can achieve different structures and properties.

Structural and Performance Changes

By precisely controlling the heating, holding and cooling processes, a series of structural and performance changes can be achieved, including the adjustment of grain size, the occurrence of phase transitions, and the change of residual stress. These changes directly affect the mechanical properties, heat resistance, corrosion resistance and other aspects of the material.

To sum up, heat treatment is an important process that changes the structure and properties of metal materials by controlling their heating and cooling processes. Precise process parameter control is the key to achieving ideal heat treatment results.