Research On Simulation Technology And Process Of Carburizing Heat Treatment For Bearing Rings Of High-speed Rail

In order to meet the service performance requirements of high-speed railway bearing rings,the carburizing heat treatment are generally performed on the surface layer.There is a gap between domestic carburizing heat treatment process of high-speed railway bearing rings and foreign advanced processes.The service life of the ring is short and its process stability is poor.It is necessary to combine the specific ring material to optimize the carburizing process.This article focuses on testing of the specific bearing ring material and its performance,establishes the constitutive equation of the carburizing heat treatment analysis of rings,and carries out research on the carburizing heat treatment process using the method of combining simulation and experiment.discusses the effects of carburizing temperature,carbon concentration and carburizing time on the heat treatment results,which provids a scientific basis for the improvement of carburizing heat treatment process parameters.The main achievements of the paper are as follows:The chemical composition,carbon content,microstructure and hardness of the R70 bearing ring material of Japan NSK Company were determined by testing.The bearing ring material is G20 Cr Ni2Mo A bearing steel.Carry out the research on the constitutive relationship of G20 Cr Ni2Mo A bearing steel and constructed a carburizing simulation model.And through the experimental research on the carburizing heat treatment sample,the effectiveness of the simulation model was proved.The effects of three process parameters of carburizing temperature,carbon concentration and carburizing time on the heat treatment results are discussed in depth.The results showed that as the carburizing temperature increases,the carbon content of the carburized surface of the bearing ring increases,the depth of the carburized layer increases,the speed of carburizing process becomes faster,the hardness of the surface increases,and both the carbon content and hardness gradient of the carburized layer from the surface to the center tend to be gentle;as the carbon concentration in the carburizing environment increases,the carbon content of the carburized surface increases,the depth of the carburized layer increases,the speed of carburizing process becomes faster first,and then changes slower,the hardness of the surface increases,and both the carbon content and hardness gradient of the carburized layer from the surface to the center tend to be steeper;as the carburizing time increases,the carbon content of the carburized surface of the bearing ring increases,and the depth of the carburized layer increases,the speed of carburizing process does not change,the hardness of the surface increases,both the carbon content and hardness gradient of the carburized layer from the surface to the center tend to be gentle.According to the influence law,the heat treatment process of the bearing ring was adjusted.While the heat treatment production efficiency is improved,the heat treatment results are also more ideal.In summary,the simulation method of the carburizing heat treatment process constructed in this paper can provide scientific guidance and technical support for the improvement of the carburizing heat treatment process.The proposed carburizing heat treatment process improvement scheme combined with the simulation results is feasible and has certain engineering Value.