The anti-rust stainless steel ball has strong water quenching and cooling ability, and the layered structure in the workpiece is coarse. When working, there is a hard tissue near the core, which makes the core toughness of the workpiece poor, and there is a hidden danger of crack cracking. After quenching, the workpiece is not tempered in time. After quenching, the stress is high and is not eliminated and released, which causes the steel ball to crack and damage. According to the analysis, the quenching and cracking of the bearing steel ball is closely related to the forging and heat treatment process. If the heating time or temperature of the forging is improperly controlled, the steel ball is overheated or over-fired, so the crystal grains are coarse and the toughness of the workpiece is lowered. On the other hand, the forging deformation of the central part of the west 120mm steel ball is small, and the cooling rate is also small. Therefore, the recrystallized grains in this part are coarse, and the cracking of the steel ball is most likely to occur first in the middle.
The anti-rust stainless steel ball to prevent cracking process improvement measures are as follows:
1. Anti-rust stainless steel ball forging, increase the forging ratio, and strictly control the forging process during operation, so as to prevent the coarsened core structure after forging.
2. Reduce the quenching water temperature of the bearing steel ball and increase the water temperature, which can significantly reduce and alleviate the quenching stress of the workpiece.
3. Add spheroidizing annealing before quenching, refine the structure, and make the workpiece quenched into fine needle-like (small sheet) martensite to prevent coarse structure after quenching.
4. Tempering in time after quenching, eliminating quenching stress, stabilizing the structure, and further removing the hidden danger of cracking of the workpiece.
5. After the above process is improved, the FAG bearing steel ball quenching cracking failure phenomenon is eliminated, the workpiece is excellent in heat treatment after heat treatment, and the production operation is good.