Steel balls are mainly used in industry. Many products are involved in it, since it is a basic building block and it can be said that it exists where most of the rotations are. The steel ball is a very small part, but there are many parts that cannot be separated from it. There are many branches of steel balls, of which carbon steel balls, steel balls and bearing steel balls are three categories.
With the development of society and the continuous improvement of the market's quality requirements for steel balls, the group using steel balls has higher and higher quality requirements for steel balls, which used to meet the use requirements at a lower level, but now, most customers upgrade and require quality, and the higher the quality of steel balls, the more popular they are.
The changes that occur after heat treatment of bearing steel balls, from the analysis of heat treatment process, bearing steel balls are not spheroidized annealed due to the quenching of residual heat after forging, so the grains are coarse and have a band structure; At the same time, quenched martensite has a high carbon content and enters quenching after forging. The high temperature increases the quenching stress of the steel ball
In addition, the bearing steel ball water quenching cooling capacity is strong, the internal layered structure of the workpiece is thick, and there is a harder structure close to the core, so that the toughness of the workpiece core is poor, and there is a risk of hidden cracking. The workpiece is not tempered in time after quenching in production, and the stress after quenching is very high, and it is not eliminated and released, resulting in cracking and damage of the steel ball.