Research On Metal Flowline Evolution And Process Optimization Of Bearing Ring For High-speed Rail

As a key component of the high-speed rail transmission system,the bearing ring is subjected to much larger radial force and axial force in a single direction in the working environment,therefore,it is required high load-bearing capacity and high reliability.For small and medium-sized bearing rings,the traditional forging process is roughly upsetting,shaping,piercing with flattening end faces,ring rolling.The process is too long and the forming parameters are numerous,so it is hard to controll the manufacturing quality of the bearing ring.Moreover,the main failure mode of the bearing ring is fatigue spalling,and the metal flowline has an important influence on it.Most of the current works focus on the design of the ring blank and the ring rolling process,and the research on the metal flow lines of the bearing ring is less.Therefore,with theoretical analysis,finite element simulation and forming experiment method,the metal flow line evolution law and control optimization method in the bearing ring forming process are studied by this thesis.Based on the plastic processing theory,the design method on blank size of rectangular bearing ring is studied,and the formula for calculating the size of rectangular ring blank is deduced.According to different blank design principles,three kinds of ring blanks for special-shaped bearing rings are given.The design method of the external single-cone ring blank is verified by finite element simulation and forming experiment.the finite element model of the forming process of the rectangular bearing ring is established,and the reliability of the model is verified by an experiment.Based on the reliable finite element model,the evolution law of metal flow lines and the formation mechanism of the defects of the metal flowlines are revealed.The influence of blank size and forming parameters on the metal flow lines of rectangular bearing rings is discussed.Finally,the forming process is optimized based on the metal flowlines.Based on the above research,the finite element model of the forming process of the special-shaped bearing ring is established.According to analysis on the simulation results,the evolution law of the metal flow line and the formation mechanism of the defects of the metal flowlines are revealed.The influence of the shape and size of the blank and the forming parameters on the metal flow lines of the special-shaped bearing ring are discussed,and then the forming process is optimized based on the metal flowlines.