Study On The Corrosion Resistance Of GCr15 Bearing Steel After Strengthened Grinding In Neutral Salt Spray Environment

GCr15 bearing steel is one of the most commonly used high chromium bearing steel in industry,which can be used to manufacture bearings and other mechanical parts.As a key component of high-end equipment,the corrosion resistance of GCr15 bearing steel needs to be improved in marine environment,and it is easy to be corroded by chloride ion,which results in bearing failure,the concentrations of chloride ions in the automobile industry,Electric Power Industry,transportation industry,marine engineering equipment and aerospace equipment in the coastal areas are higher than those in the inland areas,the corrosion resistance of bearings directly affects the performance of mechanical equipment.Therefore,in this paper,theoretical analysis,numerical simulation and experimental study are combined to explore the mechanism of strengthened grinding to improve corrosion resistance,the corrosion resistance of GCr15,Cronidur30 and CSS42L bearing steels was investigated and compared,and the results were as follows:（1）Based on the velocity field of COMSOL horizontal transport equation to calculate the dissolution rate of iron and the deposition rate of corrosion products,a physical model for numerical simulation of salt spray corrosion morphology was established to simulate the evolution of corrosion morphology of bearing steel in atmospheric environment,according to the corrosion depth and corrosion evaluation mechanism,the flow of electrolyte will produce IR drop.（2）The corrosion model of bearing steel was established,and the mechanism of corrosion evaluation of interface layer was put forward,and the variation law of corrosion crack,corrosion hole and corrosion product accumulation of GCr15 bearing steel under different intensities of grinding and spraying angle was explored,the dislocation density,grain size and SEM corrosion morphology were used to analyze the corrosion mechanism.With the increase of the spray angle,the dislocation density increased,the grain refinement results in the formation of dense surface structure,the formation of dense rust layer in the surface layer under corrosive environment leads to Cl^-,H⁺,Fe²⁺,O deficiency,the pearlite will dissolve,the matrix structure of pearlite ferrite,Fe₃C will form corrosion couple,the main corrosion products areα-Feoo H,δ-Feoo H,γ-Feoo H,Fe₂O₃,Fe（OH）₃,Fe₃O₄.The rust layer of the strengthened grinding sample has protective effect on the matrix material,the corrosion resistance of bearing steel can reach 4 grades after strengthened grinding.（3）Tracing the Tafel curve and electrochemical impedance spectroscopy（Eis）to quantify the corrosion rate,with the increase of the injection angle,the EIS capacitive arc increases gradually,the R_ctvalue of the equivalent circuit increases gradually,the self-corrosion potential increases and the self-corrosion current density decreases,in the process of strengthened grinding,the surface structure of the Matrix is highly dislocated,forming dense surface structure,which results in the formation of dense corrosion product layer in the corrosion stage and effectively blocks Cl^-corrosion.