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IKO Bearing Failure Mode Explanation

Writer: Eric Bearing Limited

Bearing failure is a common problem during bearing operation. The common forms of bearing failure include fatigue failure, wear failure, corrosion failure, galvanic wear, plastic deformation and cracks. Today Eric Bearing Limited will explain IKO bearings to you Invalidation form, I hope to help everyone.

1. Fatigue failure

This kind of bearing fatigue failure is a form of failure surface, mainly manifested in the initiation, propagation and fracture process of fatigue cracks, and the long-term effects of load failures produced by the alternate metal. The main forms of fatigue failure are subsurface fatigue and initial surface fatigue.

The main forms of subsurface fatigue are: fatigue spalling phenomenon, edge partial load, indentation and impact.

The main forms of initial surface fatigue are: the process of wear caused by improper lubrication.

The causes of the cracks are in two aspects:

(1) On the surface, this is due to the effect of external load caused by the cyclical changes in the plastic deformation of the working surface and the contact stress of the strain-hardened surface, and finally small cracks develop from the inner surface, between the two The formation of surface cracks between the work surface, due to the penetration of lubricant on the work surface, the opening force, severely hit the wall, forcing the crack to advance;

(2) From the surface layer, under repeated pressure, the contact of the surface, the initial cracks at a certain depth of the exposed surface, and the angle along the surface direction, to a certain depth, from the surface of the contact surface, and Go beyond the surface, and eventually form an eclipse, leaving a horse pit.

On the surface, it is still from the cracks in the surface layer. These two goals (parts carburization, quenching and other surface heat treatment, afterwards, if there are uneven hardness, structure, and non-uniform internal stress and other disadvantages, then the contact stress is normal Under the influence of the opposite underground cracks, if the surface quality of the parts is poor, there is a defect (oxidation, decarburization), friction or lubrication is not good, from the surface cracks.

2. Wear 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 bearing parts, and eventually lead to loss of IKO bearing dimensional accuracy and other related problems. Wear may affect the shape change, the increase of the fit gap and the change of the working surface topography, which may affect the lubricant or make it contaminate to a certain degree, causing the lubrication function to be completely lost, thus causing the bearing to lose rotation accuracy and even fail to operate normally. Wear failure is one of the common failure modes of various bearings.   IKO TLA 4012 Z online , if you are looking for , pls contact us . 

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

Abrasive wear refers to the wear caused by foreign hard particles or hard foreign matter or metal surface wear debris between the working surfaces of the bearing and the relative movement of the contact surfaces. It often causes furrow-like scratches on the working surface of IKO bearings. Hard particles or foreign matter may come from the inside of the host or from other adjacent parts of the host system, which are sent into the bearing by the lubricating medium.

Viscous wear refers to the uneven force on the friction surface due to microscopic protrusions or foreign objects on the friction surface. When the lubrication conditions are severely deteriorated, the local friction generates heat, which can easily cause local deformation of the friction surface and friction microscopic welding. At this time, the surface metal may be partially melted, and the force on the contact surface tears the local friction welded point from the substrate and increases the plastic deformation. This adhesion-tear-sticky cycle process constitutes viscous wear. Generally speaking, slight viscous wear is called abrasion, and severe viscous wear is called bite.

Generally, the main reasons for IKO bearing wear failure are as follows:

(1) Poor installation quality: Poor adjustment of IKO bearing clearance and poor adjustment of the center of the rotating device can cause uneven force and wear of the bearing.

(2) Inadequate maintenance and insufficient lubrication. IKO bearings generate heat during dry grinding.

(3) Factors such as poor quality of lubricating oil or poor use conditions cause premature wear of IKO bearings.

(4) The selection of IKO bearings is unreasonable. Non-thrust bearings are used as thrust bearings or small bearings are subject to heavy objects.

(5) The working environment is bad, and foreign matter from the outside enters the IKO bearing to cause wear.

3. Corrosion failure

The main cause of bearing corrosion:

(1) In the production process of IKO bearings, the rust-proof treatment of the bearing parts during the processing and the finished bearing products after assembly was not strictly carried out in accordance with the cleaning and rust-proof regulations and the requirements of the oil seal and rust-proof packaging. If the turnover time of the ferrule is too long in the turnover process, the outer circle of the outer ring is in contact with corrosive liquid or gas.

(2) The quality of anti-rust lubricating oil, cleaning kerosene and other products used in production does not meet the requirements of process technology, and special solvent-based hydrocarbon cleaning agents and lubricating oils must be used instead.

(3) The environmental conditions are poor, the content of harmful substances in the air is high, and the turnover space is too small to carry out effective anti-rust treatment. Coupled with the hot weather, there are also phenomena such as violations of anti-rust regulations by production workers.

(4) The turning allowance and grinding allowance of IKO bearing rings are too small, and the oxide scale and decarburization layer on the outer circle cannot be completely removed.

4. Electrical erosion

The electro-erosion of IKO bearings means that when current flows through the contact part of the rolling bearing race wheel and rolling elements, sparks are emitted through a thin lubricating oil film, and the surface thereof is locally melted and uneven.

Electric current is usually an unavoidable reality in bearing applications. When current passes through IKO rolling bearings, it has potentially destructive consequences. Damage mainly occurs on the contact surface between the ball or roller of the bearing and the raceway of the inner and outer rings.

In response to this long-standing electrical corrosion problem, a solution has been found: an insulated bearing protected from current damage, namely INSOCOAT, whose coating protects the bearing from damage caused by current. By examining all the components that constitute the electrical system of the rotating bearing, including lubrication, IKO believes that it can reduce the current in the bearing to a harmless level.

5. Plastic deformation

Plastic deformation of IKO bearings includes three types: plastic deformation generated during installation, bearing overload, and indentation caused by impurities.

(1) The main causes of plastic deformation of the bearing are:

a. Plastic deformation during installation

During the installation process of IKO bearings, steel hammers cannot be used directly, and the installation force of the bearings cannot be transmitted through the rolling elements, otherwise plastic deformation will occur and the bearings will be damaged. This kind of damage is mainly manifested in the change of the shape of the bearing parts, so the failure traces under different working conditions are different, and it needs to be analyzed in detail.

b. IKO bearing overload

When the IKO bearing is subjected to excessive static load, the rolling elements or raceways will undergo plastic deformation. From the knowledge of the load trajectory introduced above, it can be inferred that the bearing is subjected to a very large axial load, resulting in plastic deformation.

c. Indentation caused by impurities

If the lubricant inside the IKO bearing is contaminated by impurities, the contaminated particles will cause tiny indentations on the surface of the rolling element raceway, thereby destroying the surface morphology of the raceway or rolling element, generating heat or noise. People once mistakenly believed that due to the relatively high hardness of steel, some small pollution would not have an impact. In fact, those seemingly soft small pollution impurities would still microscopically change the surface finish of the raceway, destroy lubrication and cause heat. There is a special situation, in fact, more solid pollution particles are impurities in the electrical plant. Some of the damage traces of these impurities to the raceway can be directly identified with the naked eye, and some can be found only with the help of a microscope. To reduce the indentation damage caused by impurities to the bearing, it is necessary to pay special attention to the cleanliness of the bearing during installation and use, and to ensure that the bearing has a reasonable seal protection.

6. Cracks

The main cracks of IKO bearings are: cracks caused by violent beating, cracks caused by fatigue, and cracks caused by heat.

(1) Cracks caused by violence

There are two main reasons: the concentrated stress exceeds the tensile strength, impact and excessive stress.

(2) Cracks caused by fatigue

The main reason is: the fatigue strength is exceeded under the bending action, cracks begin to appear and spread, and finally cracks are formed.

(3) Cracks caused by heat

There are three main reasons: over lubrication or insufficient lubrication, high friction strength generates heat, and cracks appear in the correct angle of the sliding direction.