How to investigate Bearing failure - Unveil the root clause

Posted by Bruce Clark on March 26th, 2021

Rolling bearings are the essence of most vehicles and machines. When the bearings fail, the machine or car stops. We can say the bearing is often the victim and not the root problem. Therefore, it is vital to investigate the performance of bearing failure analysis. And find the source of the failure problem and prevent it from recurring.

As a bearing manufacturing company, you should do a proper investigation and know what type of clues to look for. This investigation begins with the simple inspection of the bearing's surfaces. During the operation, you change the difference in bearing look and will occur over time. These changes are called a pattern, and it provides information about the condition of bearings' life.

Here we discussed how to learn to solve the mystery of bearings failure.

1. Cracks and spalling

Small cracks or micro-spalling are the results of material fatigue. It can occur on the surface or subsurface. The subsurface-initiated fatigue is created by cyclic stress underneath the raceway surface. Results in the decay of the material. Cracks are initiated underneath the surface, and when they come to the surface, spalling occurs.

On the other hand, surface-initiated fatigue results from inadequate lubricant conditions. When the incorrect coherence or metal to metal occurs, the surface peaks shear over each other and shear stresses at the surface. The bearings and bushings surface is shiny at the initial stage, and the roughness is minor. But the continued process of the surface becomes dull and breaks more and more.

2. Abnormally dull

Corrosion is determined; two circumstances may be preventable wear: abrasive and adhesive.

Abrasive wear: The lubricant impurity particles and the abrasive particles carry out the raceways' surfaces and rolling elements. The result is that surfaces become dull. However, the abrasive particles are very hard, cement dust, and a polishing effect might occur.

Adhesive wear: This corrosion occurs in the contact surfaces when subjected to light loads, insufficient lubrication or difference in speed. The rolling bearing from the unloaded zone into the loaded area. And early-stage adhesive corrosion appears in shiny surfaces. But it quickly turns into dull surfaces with less covered material.

3. Black etching

Black etching in the rolling elements is more corrosion. There are two common reasons for the corrosion, bearing exposure to moisture or fretting.

Moisture corrosion: It occurs when the water is present, corrosive liquid or moisture, the reasons for the bearing failure. In contrast, the other damages and corrosion can fast and penetrate deep into the material.

Fretting corrosion: It occurs between two loaded surfaces, the bearing outside diameter and the bearing bore and shaft. Bearings don't fail, but the problem of observation indicates inadequate fitting, shaft bending, or imperfection in the contact surfaces. The black etching marks are also visible, and they can develop material growth and high stresses. 

4. Discoloration

The rolling elements reveal the color changes; the bearing can be overheating due to insufficient lubricant or a variety of other culprits.

Overheating: The result can be discoloration of the rings, balls, and cages. The result of loss in hardness reduces the capacity of bearing and causing early failure. In some cases, balls and rings will deform. The common accused are heavy electrical loads, inadequate heat path, insufficient lubricant or cooling, or the loads and excessive speeds.

5. Deformation

Dents and deformation are characterized by the damage to the raceway's geometry at the dent's location. And often associated with disruption of lubrication. The debris results of the different particles have gained the entry level of the bearings and rolled into the raceways by the rolling elements. The volume and shape of the dents, it depends on the type of the particles.

85% bearing failures are preventable

To solve the failure with in-depth investigations, it requires decoding the physical proof left on the bearing's surface. This will ultimately reveal the role of bearings as the victim and uncover the large culprit, which is the reason for the failure. Taking the proper action, you can reduce the source's issue and minimize the future bearing loss.

In summary:

The Hi-bond Bearings Pvt. Ltd. maintenance technology department uses state-of-the-art diagnostic equipment. Analyze the dynamic machine and performance, identifying misalignment and the imbalance issues. These are the reasons for vibration and excess wear and tear on the rotating equipment.