Analyzed the INA whole eccentric bearing life and material quality requirements

When the original organization of fine carbide hours, because the carbide is easy to dissolve in austenite, thus make the hardness after quenching peaks move to low temperature and occur in a relatively short austenitizing time in order to make the material factors affecting the service life of INA bearings in the best state, you first need to control of the original organization before quenching steel, can take technical measures are: high temperature ( 1050℃) Austenitizing rapid cooling to 630 ℃ isothermal normalizing get false eutectoid pearlitic structure, or cold to 420 ℃ isothermal treatment, obtain bainite structure can be used also forged heat rapid annealing, obtain fine granular pearlite structure, to ensure that the carbide steel small and evenly distributed in this state of the original organization when austenitizing quench heating, in addition to into the austenite carbides, not soluble carbide will gather into fine granular whole eccentric bearing to tensile, compression, bending, shear, alternating under complex stress state and high stress value, such as high speed, work over a long period of time. Therefore in the process of production, the quality of bearing steel to control inspection items, control and narrow, strict production process, complex, and requires a certain tooling equipment, testing means and a certain level of technology of villain. In order to ensure that the service life of bearing has good performance and high, the quality requirements for bearing steel is as follows: ( 1) Chemical composition: the chemical composition is the most essential factors of the bearing steel. Steel of physics, chemistry, mechanical properties and microstructure are determined by the chemical composition, change the chemical composition, changed the basic properties of the steel. Therefore, the chemical composition of bearing steel must conform to the standards stipulated by the permissible range. ( 2) Internal quality: can be divided into macro and micro quality. Macro quality: the interior of the bearing steel is not allowed to have white spots, shrinkage, slag inclusion, metals, defects such as crack, burnt, subcutaneous bubbles. Overall eccentric bearing steel internal segregation, the loose control within a certain range. All in all, the interior of the bearing steel to dense, there is no visible defects between steel substrate. ( 3) Surface quality: INA bearing parts molding method, there are forging, turning and cold punching etc. According to the different processing methods have different levels of requirements for steel quality. In general, the bearing steel surface can not have crack, folding, cracking, scarring and slag. To cold with cold drawn steel, in addition to not allow the above defects, the surface to clean, can not have defects such as rust, MaAo. Bearing steel surface can not have serious decarburization phenomenon, according to the different requirements of the eccentric bearing parts molding process, in the standard, on steel surface decarburization layer depth in different varieties have different restrictions. To sum up, GCrl5 steel after quenching not dissolve carbide at about 7%, the residual austenite is around 9%, Cryptocrystalline martensite average carbon content in 0. About 55%) As the best groups and, when the original organization carbide in small, uniform distribution, the reliable control of the level of the microstructure, to obtain high comprehensive mechanical properties, which have high service life should be pointed out that a fine carbide dispersion distribution of the original tissue, quenching heat insulation, not dissolve tiny carbides would gather to grow up, make its coarsening, therefore, to have the original organization INA bearing parts quenching heating time shoulds not be too long, the rapid heating austenitizing quenching process, will can obtain higher comprehensive mechanical properties