Failure Case of Thrust Ball Bearings in Pumps!

During the operation of a horizontal multistage pump in a chemical enterprise, the thrust ball bearings suddenly experienced wear and failure. The pump model is KSB-200, with a flow rate of 150m³/h, head of 200m, and speed of 2950r/min. At the time of the failure, the bearings were in normal condition without any abnormal noise or vibration, but the bearing temperature abnormally increased, ultimately leading to bearing wear and failure. They sought our assistance to resolve this issue!

We provided the following analysis of the bearing failure causes:

1.Material Issue of Bearings

The material of the thrust ball bearings used in the pump is GCr15SiMn steel, which is a high-carbon, high-alloy steel. During the manufacturing process, improper heat treatment, uneven quenching, inadequate tempering, etc., may lead to uneven internal structure of the bearings, resulting in residual stress, embrittlement of grain boundaries, martensite, and other defects. These defects gradually expand during bearing operation, ultimately leading to bearing wear and failure.

2.Bearing Fit Issue

Both too loose or too tight fit between the inner ring of the bearing and the shaft can lead to bearing wear and failure. When the fit is too loose, there is relative motion between the inner ring of the bearing and the shaft, resulting in frictional wear. When the fit is too tight, the inner ring of the bearing is subjected to excessive compressive stress, leading to fatigue wear.

3.Excessive Bearing Load

The thrust ball bearings in the pump are subjected to excessive loads, which can easily cause bearing wear. Excessive load may be caused by factors such as unreasonable pump design, manufacturing errors, improper installation, etc. In these cases, the bearings bear excessive radial and axial loads, leading to accelerated bearing wear.

4.Poor Lubrication

Poor lubrication of the bearings is also one of the reasons for wear and failure. During the operation of the pump, if lubricating oil is not added or replaced in a timely manner, the bearing friction surfaces may lack lubrication, accelerating bearing wear.

So, what preventive measures should be taken?

1.Improve Bearing Manufacturing Quality

Adopt advanced manufacturing processes and equipment to improve bearing manufacturing quality. Strict control of processes such as heat treatment, quenching, and tempering of bearings to ensure uniform internal structure and defect-free bearings.

2.Proper Selection of Bearing Materials

Select appropriate bearing materials according to the pump's operating environment and conditions. For example, for high-temperature, high-speed, heavy-load conditions, high-strength, and wear-resistant carburized steel or alloy steel can be chosen.

3.Improve Installation Quality

Strictly follow the bearing installation requirements to ensure proper fit between the inner ring of the bearing and the shaft. Regularly inspect and maintain the pump, and promptly deal with any abnormal situations.

4.Strengthen Lubrication Management

Regularly inspect the lubrication system to ensure the quality and adequacy of lubricating oil. According to the pump's operating requirements, regularly replace the lubricating oil to ensure sufficient lubrication of the bearing friction surfaces.

5.Install Monitoring Devices

Install vibration monitoring devices and temperature monitoring devices during pump operation to monitor the operating status of the bearings in real time and promptly detect any abnormal conditions

In summary, to prevent thrust ball bearing wear and failure in pumps, preventive measures need to be comprehensively considered from aspects such as manufacturing quality, installation quality, operating conditions, and lubrication management. By strengthening quality management, selecting appropriate materials, and enhancing maintenance measures, the service life and reliability of bearings can be improved, and failures can be reduced.

38 years of professional production of thrust ball bearings for pumps!

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