‘Bearing down’ on the wear and tear of product failure …and why it might occur!

Chaoyang Runxing Heavy Machinery Manufacturing Plant was established in 2005. The business’ main products are babbitt bearings, bearing bushings and plain bearings – all used in construction and heavy machinery, and also  in industries such as electric power, metallurgy, mining and other machinery manufacturing enterprises. 

casting technologies 

Chaoyang Runxing Heavy Machinery markets successfully throughout China and also exports to Europe, Asia, Africa and the Americas. The company’s manufacturing plant has independent alloy casting  processing technologies backed by a reliable quality assurance systems and competitive pricing.

always informed 

The  company maintains its competitive pricing on its bearing products backed by the business’ responsive, always informed customer service. This latest IMD member company blogs below on aspects of common bearing failure and mechanisms for high temperature bearings….

early rotation failure

In the use of bearings, problems are often encountered, that is, the bearings are qualified after testing, but the bearings are stuck after installation or the early rotation failure during use fails. The main manifestations are the stagnation of rotation, severe peeling of the working surface, severe wear of the cage and even distortion and fracture.

Analysis of failure results shows that there are not many quality problems that belong to the bearings themselves, most of which are caused by improper installation and use. For this reason, high-temperature bearings make a superficial review of common bearing failure modes and mechanisms, in order to play a role of attracting a lot of attention. Bearing failure mechanisms:

Contact fatigue failure …..refers to the failure of the bearing working surface under the effect of alternating stress. Contact fatigue spalling occurs on the bearing working surface, which is often accompanied by fatigue cracks. It first occurs from the large alternating shear stress below the contact surface, and then expands to the surface to form different spalling shapes, such as pitting or pitting. Exfoliation into small pieces is called shallow exfoliation. Due to the gradual expansion of the exfoliation surface, it often expands to the deep layer, forming a deep exfoliation. Deep spalling is the fatigue source of contact fatigue failure.

Wear failure…… refers to the failure caused by the continuous wear of the metal on the working surface caused by the relative sliding friction between the surfaces. Continued wear and tear will cause gradual damage to the bearing parts, eventually leading to loss of bearing dimensional accuracy and other related problems. The wear may affect the shape change, the increase of the fit clearance and the change of the topography of the working surface, which may affect the lubricant or make it contaminated to a certain extent and cause the complete loss of the lubricating function, thus causing the bearing to lose its rotational accuracy and even fail to operate normally. Wear failure is one of the common failure modes of various types of bearings. 

Abrasive wear…..refers to the wear caused by the intrusion of hard particles or hard foreign objects or abrasive debris on the surface of the bearing between the working surfaces of the bearing and the relative movement of the contact surface, often causing furrow-like abrasions on the working surface of the bearing. Hard particles or foreign objects may come from the host or from other adjacent parts of the host system and are fed into the bearing by the lubricant. 

According to the form of wear, it can be divided into common abrasive wear and adhesive wear.

Adhesive wear…. refers to uneven friction on the friction surface due to micro-protrusions or foreign objects on the friction surface. When the lubrication conditions are seriously deteriorated, local friction generates heat due to local friction, which can easily cause local deformation of the friction surface and friction micro-welding. When the surface metal is partially melted, the force on the contact surface will tear the local friction welding point from the substrate and increase plastic deformation. This cycle of adhesion-tearing-adhesion constitutes adhesive wear. Generally speaking, slight adhesive wear is called abrasion, and severe adhesive wear is called bite.

Fracture failure…. The main reason for bearing failure is the two major factors of defect and overload. When the applied load exceeds the strength limit of the material and the part breaks, it is called overload fracture. The main reason for overload is sudden host failure or improper installation. Defects such as micro-cracks, shrinkage holes, air bubbles, large foreign objects, overheated tissues, and local burns of bearing parts can also cause fractures at the defects during shock overload or severe vibration. It should be noted that during the manufacturing process of the bearing, the original inspection of raw materials, forging and heat treatment quality control, and process control can be used to correctly analyse the existence of the above defects through instruments. In the future, control must be strengthened. But in general, the most common bearing fracture failures are overload failures.