Study On Diffusion Process And Microstructure And Properties Of FeS Coating On 40Cr Surface

Gear transmission is one of the most important transmission methods in mechanical transmission,but there is friction and wear on the meshing surface during gear transmission.In order to improve the performance and life of gear materials,the traditional methods are to increase the surface hardness of the material and use lubricants.Measures are not always effective in all cases.Increasing the surface hardness of the material will reduce the surface toughness of the ma terial,reduce the fatigue resistance and accelerate the wear on the abrasive parts,and the lubricant will lose its lubricating effect under extreme working conditions.Therefore,how to improve the self-lubricating performance of gear materials and reduce material loss and energy consumption is of great significance.The results show that:?1?The simulation analysis found that under the same load condition,the contact pressure was mainly affected by the thickness of the outermost layer.When carburizing of low carbon steel,the sensitivity of carburizing layer thickness to contact pressure is positively correlated;when carburizing and chromizing of low carbon steel,the sensitivity of chromizing layer thickness to contact pressure is positively correlated;when carburizing and chromizing and sulfurizing of low carbon steel,the sensitivity of FeS layer thickness to contact pressure is negatively correlated.By analyzing the fatigue life of the rollers,it was found that under the same load conditions,the low carbon steels have undergone yield failure;the carburizing of low carbon steels has increased the material life to 95009times;the carburizing and chromizing of low carbon steels Compared with low-carbon steel,the service life is increased by 1.5 times when compared with low-carbon steel;when carburizing and chromizing and sulfurizing of low carbon steel,the life is increased by 6 times compared with that of low carbon steel carburizing.?2?The optimal salt solution temperature for chemical bath deposition sulfurizing is 50?,because the coating is mainly composed of Fe_xS_y(FeS,FeS₂ and Fe_1-x-x S)and the highest FeS content in this temperature range,and the FeS coa ting is chrysanthemum,Composed of FeS crystals.The chrysanthemum-like particles began to nucleate at about 40?,grew rapidly at 50⁷0?and reached a peak thickness,disappeared at 90?and were replaced by disorderly thick petals.After chemical bath deposition and sulfurizing treatment,the wear resistance of steel is significantly improved.This is because the coating after sulfurization can provide better lubrication in long-term friction tests and improve the wear resistance of steel.?3?The optimum temperature for low temperature ion sulfurizing is 190?,because at this temperature,the film is mainly composed of FeS and FeS₂,and the ratio of FeS/FeS₂ is the largest,and the FeS content is the largest.The surface of the lubricating film is composed of nano-spherical particle bump.The main components of nano-spherical particle bump are FeS and FeS₂.The nano-spherical particle bump continue to grow as the temperature increases,and the growth rate reaches 210?to230?maximum.After low temperature ion sulfurizing treatment,the wear resistance of steel is significantly improved,because the film formed after sulfurized can provide better lubrication and improve the wear resistance of steel.In this article,chemical bath deposition sulfurizing is to immerse the workpiece in the liquid,which has no requirements on the size and shape of the workpiece,and the chemical bath deposition sulfurization speed is fast,the quality of the infiltration layer is good,the thickness is moderate,pollution-free and cheap.When double-layer glow low-temperature ion sulfurization,the dual-power supply is used to control the workpiece temperature and the sulfur tank temperature respectively,which solves the disadvantage that the workpiece and the sulfur tank can only use the same power source to control the temperature during traditional low-temperature ion sulfurization.