Failure modes and measures of ball bearings - Overview of ball bearing life and failure
Approximately 10 billion bearings are produced worldwide each year. In fact, only a small portion of the bearings in use will fail, and the lifespan of most bearings (about 90%) is longer than the maintenance cycle of the equipment in which they are installed. For safety reasons (prevention), some bearings (9.5%) are replaced before they fail, and about 0.5% of bearings are only replaced after damage or failure. This means that approximately 50 million bearings are replaced each year due to damage and failure. The reasons for bearing damage or failure are usually as follows:
1/3 of failures are caused by fatigue;
1/3 of failures are caused by lubrication issues (inappropriate lubricant dosage, unreasonable lubrication interval);
1/6 of failures are caused by pollution (seal failure);
1/6 of failures are caused by other reasons (improper transportation and installation, loading greater than or different from expected values, incorrect or insufficient coordination).
The above data may vary in different industries or applications. For example, in the pulp and paper industry, the main causes of bearing failure are pollution and insufficient lubrication, rather than fatigue.
Each type of failure will result in a special damage imprint, which is called a "trace" (referred to as a "trail" in the raceway). Therefore, in most cases, the root cause of damage can be identified by carefully inspecting the damaged bearings. Based on the cause of the damage, corresponding corrective measures can be taken to prevent the problem from happening again.
Taking the application of seal failure as an example. After the pollution particles pass through the seal and enter the bearing, they will be crushed by the rolling elements and will form indentations on the raceway (see the figure below), and harder particles may form indentations with sharp edges. Afterwards, the area around the indentation will experience cyclic stress under normal rolling of the rolling element, resulting in surface fatigue, and this part of the metal begins to detach from the raceway. This phenomenon is called peeling, and once peeling occurs, the damage will further increase until the bearing cannot be used.
The development of damage：
Hard pollutants are crushed, forming indentations on the inner raceway of stainless steel deep groove ball bearings (a).
Surface fatigue occurs from the area behind the indentation, leading to peeling. After a period of time, the peeling becomes increasingly apparent (b, c).
If the equipment is not shut down in a timely manner, it may cause secondary damage to the components. The initial indentation becomes unrecognizable (d).
Thank you for following my article.
We are a manufacturer with over 20 years of experience in bearing production.
The main products include: deep groove ball bearings, injection molded pulley series, as well as OEM customization services for various deep groove ball bearings and injection molded pulleys.
If you would like to learn more details, please feel free to contact me at any time. Thanks again!
Best regards!
