Choose 20# material filter cover, processing technology has warm forging, The forging process of the product is essential to heat treatment, one of the procedures is annealing, is to heat the steel whose organization deviates from the equilibrium state to the appropriate temperature, heat preservation to a certain time, and then slowly cooling.

The other process is tempering. The purpose of tempering is:
1. Reduce brittleness, eliminate or reduce internal stress, there is a lot of internal stress and brittleness of steel after quenching, such as not tempering in time often make steel deformation and even cracking.

2. Obtain the mechanical properties required by the workpiece, the workpiece after quenching high hardness and brittleness, in order to meet the requirements of different performance of various workpiece, can be adjusted by appropriate tempering with hardness, reduce brittleness, get the required toughness, plasticity.

3. Stabilize the workpiece size.

4. For some alloy steel that is difficult to soften by annealing, high temperature tempering is often used after quenching (or normalizing), so that the carbide in the steel is properly aggregated, and the hardness is reduced to facilitate cutting.