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Causes of fracture of imported bearing cages and factors affecting bearing performance
Bearings play an important role in social life. Bearings are composed of cages, outer rings, rolling elements, and inner rings. Different types of bearings, bearing components, and bearing bearing cages have different causes.
Creep phenomenon is also one of the causes of cage fracture. The so-called creeping multi-finger sliding phenomenon occurs when the mating amount of the mating surface is insufficient, the load point is moved in the direction of the circumference due to sliding, and the position of the ferrule relative to the shaft or housing in the circumferential direction is deviated. Once the creep occurs, the mating surface wears significantly, and the wear powder may enter the bearing interior, causing abnormal wear, raceway spalling, cage wear and additional load processes, which may cause the cage to break.
Holder abnormal load. If the installation is not in place, tilting, excessive interference, etc. can easily cause reduction in clearance, increase friction heat, surface softening, premature flaking, with the expansion of spalling, peeling foreign matter into the cage pocket, resulting in maintaining Block operation and additional load will increase the wear of the cage. With such a deteriorating cycle, the cage may break.
Defects in the cage material and riveting defects can cause the cage to break. Take countermeasures to strictly control the manufacturing process. The intrusion of foreign bodies is a common mode of failure of cages. Due to the intrusion of foreign hard foreign materials, the wear of the cage and the generation of abnormal additional loads are exacerbated, and the cage may also be broken. The
Poor lubrication refers mainly to bearing operation in a lean state, which tends to cause sticky wear and deterioration of the working surface. Tears generated by adhesive wear easily enter the cage, causing abnormal load on the cage, which may cause the cage to break.
Bearings play an important role in the field of machinery. Bearings feel to me that bearings can be used not only in machinery but also in some craft toys. Bearings have a major impact on our lives.
What are the factors affecting bearing performance? The following analysis is performed. The smelting quality and basic requirements of bearing steels The service life and reliability of rolling bearings are closely related to the quality of steel used in bearing steels. Bearing steel smelting requires much more stringent than general industrial steel.
High-precision size requirements Rolling bearing steels require high dimensional accuracy because most bearing parts are pressure-formed. In order to save material and increase labor productivity, most of the bearing rings are forged. The steel balls are cold-formed or hot-rolled. Small-sized rollers are also cold-formed. If the dimensional accuracy of the steel is not high, the size and weight of the blank can not be calculated accurately, and the product quality of the bearing parts cannot be guaranteed, and the equipment and the die can be easily damaged.
Particularly stringent carbide non-uniformity requires that in the case of bearing steels, if there is a serious non-uniform distribution of carbides, the unevenness of the structure and hardness is likely to be caused during the heat treatment process, and the non-uniformity of the steel against the contact fatigue strength. Have a greater impact. In addition, severe carbide inhomogeneity is also easy to cause cracks in the quenching of bearing parts, and the non-uniformity of carbides also leads to a reduction in bearing life. Therefore, in the standard of bearing materials, steels of different specifications are clearly defined. special requirement.
Strict chemical composition requirements General bearing steel is mainly high-carbon chromium bearing steel, that is about 1% of carbon content, adding about 1.5% of chromium, and contains a small amount of manganese, silicon, hypereutectoid steel. Chromium can improve the heat treatment performance, improve hardenability, organizational uniformity, tempering stability, but also can improve the rust resistance of steel and grinding performance. However, when the chromium content exceeds 1.65%, the retained austenite in the steel after quenching increases, the hardness and dimensional stability decrease, the non-uniformity of the carbide is increased, and the impact toughness and fatigue strength of the steel are reduced. For this reason, the chromium content in high-carbon chromium bearing steels is generally controlled below 1,65%. Only the strict control of the chemical composition of the bearing steel can obtain the structure and hardness that meets the bearing performance through the heat treatment process.
Particularly stringent surface defects and internal defects are required for bearing steels. Surface defects include cracks, slag inclusions, burrs, scabs, scales, etc. Internal defects include shrinkage, air bubbles, white spots, severe loosening, and segregation. These deficiencies have a great influence on bearing processing, bearing performance and life. It is clearly stated in the bearing material standards that these deficiencies are not allowed.