Factor analysis in determining the quality of KOYO bearing problem

Bearing materials of metallurgical quality were the main factors influencing the KOYO bearing early failure. As metallurgy technology, For example, the bearing steel vacuum degassing, etc. ) Progress, raw material quality is improved. Raw material quality factor in the bearing failure analysis share has declined obviously, but it is still one of the main influence factors of bearing failure. Select material adequacy is still bearing failure analysis factors must be considered. Bearing manufacturing generally go through forging, heat treatment, cutting, grinding and assembly, and multi-channel processing operations. The rationality of the processing technology, advanced, stability will also affect the service life of bearing. Which affects the quality of finished products bearing heat treatment and grinding process, tend to have a more direct relationship with bearing failure. In recent years the study of metamorphic layer of bearings working surface show that the grinding process and is close to the surface quality of the bearing. The main task of the bearing service life analysis, is based on a lot of background material, analysis data and failure forms, find out the main factors of bearing failure, so that the improvement measures are put forward, prolonging bearing, avoid premature failure of the bearing of the sudden. 1, the wear failure wear failure refers to the relative sliding friction between the surface of lead to constant wear and tear of the working surface of metal. Continuous wear will cause bearing parts damaged gradually, and ultimately result in the loss bearing dimensional accuracy and other related issues. Wear may affect the shape change, the increase of fit clearance and working surface morphology change, may affect the lubricant or make its pollution to a certain degree of lubrication function is lost, so that loss of bearing rotating accuracy and will not operate properly. Wear failure is one of the common failure modes of all kinds of bearings, according to the wear and tear is usually divided into one of the most common form of abrasive wear and adhesive wear. 2, contact fatigue failure of contact fatigue failure refers to the KOYO bearing working surface under the role of alternating stress and failure. Contact fatigue spalling occurred in bearing working surface, often accompanied by fatigue crack, first of all, from the maximum cyclic shear stress under contact surface, and then extended to form a different flake shape, such as dot to pitting corrosion or pitting spalling, peel into small sheet according to the shallow flaking. Due to spalling surface expands gradually, and often to deep extension, forming deep spalling. Deep spalling is contact fatigue failure of fatigue source. 3. Fracture failure KOYO bearing failure of the main reason is that defects and overload two factors. When the loads more than material strength limit fracture caused by parts called overload fracture. Overload reason mainly is the main engine failure or improper installation. Bearing parts of micro crack, shrinkage cavity, bubbles and large foreign impurities, overheating organizations and local burns and other defects during the impact overload or violent vibration will cause fracture in defect, known as defect fracture. It should be pointed out that the bearing in the process of manufacturing, for raw materials into the factory reinspection, forging and heat treatment quality control, process control through instrument analysis of the existence of the above defects and correct still must strengthen control in the future. But in general, usually bearing fracture failure of most for overload failure. 4. KOYO bearing clearance change failure at work, because of the influence of the external or internal factors, change the original fit clearance, lower accuracy, and the change of 'killed' called clearance failure. , large amount of the external factors such as interference of installation does not reach the designated position, temperature rise caused by the expansion, instantaneous overload, etc. , internal factors such as residual austenite and the residual stress in a state of flux and so on all is the main reason for the failure caused by clearance changes.