Study Of Stress Corrosion Resistance Of CSS-42L Bearing Steel Based On Jet-intensified Grinding Process

This paper discusses the problem of stress corrosion failure of steel materials used in essential core components used in high-end equipment in complex environments.Taking the third-generation bearing steel（CSS-42L bearing steel）as the research object,focusing on its dual influence by external loads and corrosive media,the stress corrosion failure characteristics of this steel are comprehensively investigated by using theoretical analysis,simulation,and experimental validation in conjunction with the actual situation,and the intrinsic mechanism of jet intensified grinding processing on improving the stress corrosion resistance of CSS-42L bearing steel is elaborated.The main elements of this study are as follows:（1）A multi-field coupled solid mechanics-electrochemical three-dimensional finite element simulation model was established for analyzing the effect of external load on the corrosion process of the material metal and the law of action.The results show that the material’s original electrochemical corrosion-dissolution reaction equilibrium state will be out of balance due to external load,resulting in lower corrosion potential and higher corrosion current density.Compared with the external load,when the material is subjected to stress exceeding its yield strength and plastic deformation,the corrosion potential at the crack decreases by 7.04%,and the corrosion current density increases by 110.3%,indicating that the corrosion dissolution reaction rate of the metal is accelerated.（2）A jet intensification grinding test was conducted on CSS-42L bearing steel at different processing times,followed by a grain size erosion test on the processed specimens to observe the change in grain size of each group of specimens.The results showed that the grain size of the processed specimens was refined and showed a pattern of decreasing and increasing with the increase of processing time.Compared with the unprocessed specimens,the highest degree of grain refinement was observed when the injection time was 15 min,and the grain refinement was 65.97%.（3）Electrochemical corrosion tests were conducted on CSS-42L bearing steel after different jet-intensified grinding processing times,and the self-corrosion potential and self-corrosion circuit density were obtained for each group of specimens.The test results showed that the self-corrosion potential of the processed material increased,and the self-corrosion current density decreased relative to that of the unprocessed material.Among them,the specimen of the A4 group processed by jet intensified grinding for 15 min has the most significant change;compared with the specimen of the A1 group,its self-corrosion potential increased by 25.6%;self-corrosion current density decreased by 58.3%.（4）The slow strain rate tensile test method was applied to CSS-42L bearing steel to analyze its stress corrosion behavior.Meanwhile,the mechanism of the effect of jet-intensified grinding processing technology on the stress corrosion performance of CSS-42L bearing steel was investigated.The experimental results showed that the stress corrosion susceptibility of CSS-42L bearing steel material was 66.22%for I_RM,84.38%for I_A,93.39%for I_F,and 86.82%for I_swhen the specimens were subjected to 15 minutes of intensive grinding by injection.The minimum stress corrosion susceptibility coefficient was38.96%for I_RM,60.94%for I_A,85.34%for I_F,and 83.87%for I_swhen the specimens were processed by jet intensification for 15 minutes.Compared with the blank control group B1,the stress corrosion susceptibility results decreased by 27.26%,23.44%,8.05%,and 2.95%,respectively;combined with the analysis of the jet intensified grinding specimens and electrochemical test results,it can be seen that the jet intensified grinding process can significantly improve the surface tissue denseness of the specimens and refine the grains,thus reducing the possibility of local stress concentration phenomenon.Grain refinement and the increase in the number of grain boundaries make it more difficult for harmful external media to invade the surface of the material and complicate the expansion path of internal corrosion cracks,which successfully controls the formation and expansion of stress corrosion cracks and slows down the effect of external loads on the material to promote the occurrence of corrosion dissolution;at the same time,the surface corrosion products on the specimen are reduced after the jet intensified grinding process,and the surface enrichment of Cr elements occurs,which further improves The stress corrosion resistance of CSS-42L bearing steel was improved by the combined effect of mechanical strengthening and microstructural strengthening of the jet-reinforced grinding process.