How are bearing balls made? Private1 month ago - Real estate - Battambang - 15 views
The importance of steel ball crushing load test
As an important part of ball bearings, steel balls have a great influence on the life, accuracy, vibration and running characteristics of ball bearings. When the bearing works, the contact surface of the steel ball and the raceway is actively small, and the compressive stress per unit area is large, generally up to 150-500 kg/mm2.
The points on the contact trajectory of the steel ball to the raceway are cyclically stressed. Under normal circumstances, the number of cycles per minute is more than tens of thousands of times. Under the repeated action of cyclic stress, the high carbon steel ball is prone to fatigue damage. This phenomenon is called contact fatigue, which is one of the main features of the normal damage of the steel ball in the bearing. When contact fatigue reaches a certain level, it will lose its ability to work.
The crushing load of the carbon steel ball refers to the pressure value of the steel ball when it is broken. It is an important indicator of the comprehensive performance of the steel ball. There are many factors in the processing of the steel ball affecting the crushing load value of the steel ball, such as the original metallographic structure of the steel ball, the microstructure of the heat treatment and different processing methods, the geometric precision of the stainless steel ball surface and the processing time of the steel ball. And test methods for measuring the crushing load of steel balls. The crushing load inspection of steel balls is a very important task in the quality inspection of steel balls, which also plays a significant role in the life and dynamic performance of the bearings.
How are bearing balls made?
Bearing balls are the component of a ball bearing that permit smooth, friction-free rotary motion. They are typically manufactured out of steel, but can also be made from other materials such as silicon nitride ceramic, plastic or even glass.
Steel bearing balls, such as low carbon steel ball, are easily the most common ball material, with tens of millions produced annually. They are near-perfectly round and are polished with a mirror-like finish to provide precision rotary motion in machines, power tools, motors, power transmission and hundreds of other applications.
After heat treating, the balls are discolored and covered with oxide deposits. To remove these deposits, the balls are put through a process called descaling. Descaling involves using a chemical agent, usually an acidic compound, to remove the build-up on the balls.
Now that the grinding ball are hardened and relatively round, they are nearing the end of the manufacturing process. The next step is to grind the balls to size them and improve roundness geometry. The process is similar to the soft grinding process used earlier — the balls are rolled between a steel plate and a fine-grit grinding wheel.
Finished steel balls, including middle carbon steel ball.The last step in the process is to lap the balls. Lapping is a superfinishing process that improves the surface finish or geometry and removes small amounts of material so that the balls attain the tight, required tolerances.
The balls are rolled between two hardened steel plates, with one fixed and one rotating at a low speed. The balls are now perfectly round and have a mirror-like finish.
Washing and sizing
Now that the manufacturing process is complete, they are washed to remove any leftover residue. Lastly, the clean balls are inspected for scratches and sized. Even though the balls all have the same nominal outside diameter, small variances still occur. The ball grade defines the geometric tolerances of the bearing. The lower the grade number, the tighter the tolerances. The number of the grade is related to the sphericity and diameter variation of the balls. The tolerances are extremely tight and the variation between balls is quite small.