The role of heat treatment of pump parts

The main functions of heat treatment of castings are as follows: improving mechanical properties, improving processing performance, eliminating residual stress, improving corrosion resistance, and improving metallographic structure.

The main functions of heat treatment of castings are as follows:

1. Improving mechanical properties: Heat treatment can change the organizational structure of castings, so that their mechanical properties such as strength, hardness, toughness, and wear resistance are significantly improved. For example, after quenching and tempering, the strength and hardness of castings will increase significantly, and they can withstand greater loads.

2. Improving processing performance: During the casting process, castings may produce some hard spots or coarse grains, which will cause processing difficulties. Heat treatment can refine these hard spots and homogenize the grains, thereby reducing the hardness of castings, improving their cutting performance, reducing tool wear, and improving processing efficiency and quality.

3. Eliminating residual stress: During the solidification and cooling process of castings, residual stress will be generated due to uneven shrinkage of various parts. The existence of residual stress may cause deformation or even cracking of castings during subsequent processing or use. Through heat treatment processes such as annealing, residual stress can be eliminated or reduced, the dimensional accuracy of castings can be stabilized, and their reliability can be improved.

4. Improve corrosion resistance: Certain heat treatment processes can form a dense oxide film on the surface of the casting or change its organizational structure to improve the corrosion resistance of the casting. For example, after solution treatment, stainless steel castings can improve their ability to resist intergranular corrosion, making them more durable in harsh corrosive environments.

5. Improve metallographic structure: Heat treatment can make the metallographic structure of the casting more uniform and dense, eliminate casting defects such as pores and looseness, and thus improve the quality and performance of the casting. For example, normalizing can refine the pearlite structure and improve the comprehensive mechanical properties of the casting.