Material factors affecting bearing life and its control
Core Tips: 1. Material Factors Affecting Bearing Life The early failure modes of rolling bearings mainly include cracking, plastic deformation, wear, corrosion and fatigue. Under normal conditions, they are mainly contact fatigue. axis
1. Material factors affecting bearing life
The early failure modes of rolling bearings mainly include cracking, plastic deformation, wear, corrosion and fatigue. Under normal conditions, they are mainly contact fatigue. In addition to the service conditions, the failure of bearing parts is mainly limited by the hardness, strength, toughness, wear resistance, corrosion resistance and internal stress state of the steel. The main intrinsic factors that affect these performance and status are as follows.
1.1 Martensite in hardened steel
When the original structure of high carbon chromium steel is granular pearlite, the carbon content of quenching martensite under quenching and low temperature tempering obviously affects the mechanical properties of steel. The strength and toughness are about 0.5%, the contact fatigue life is about 0.55%, and the crush resistance is about 0.42%. When the carbon content of the quenched martensite of GCr15 steel is 0.5% to 0.56%, the anti-failure ability is the strongest. Comprehensive mechanical properties.
It should be noted that the martensite obtained in this case is cryptocrystalline martensite, and the measured carbon content is the average carbon content. In fact, the carbon content in the martensite is not uniform in the micro-region, and the carbon concentration around the carbide is higher than that away from the original ferrite portion of the carbide, so that the temperature at which they begin to undergo martensite transformation is different. Thereby, the growth of the martensite grains and the display of the microscopic morphology are suppressed to become cryptocrystalline martensite. It can avoid the microcracks that are prone to occur in the quenching of high carbon steel, and its substructure is dislocation-type lath martensite with high strength and toughness. Therefore, only when the medium carbon cryptocrystalline martensite is obtained when the high carbon steel is quenched, the bearing parts can obtain the substrate with the best failure resistance.
