Effect Of Laser Processing Parameters On Surface Texture Of Pin Shaft And Friction Reduction And Wear Resistance

Due to the complex Marine environment,Marine engine is in the harsh conditions of high humidity and high salinity for a long time,which seriously aggravates the friction and wear of engine chain,shortens its service life,and then affects the stability of engine.In most engineering cases,friction and wear of engine chain mainly occur on the contact surface of pin shaft and sleeve.At present,the solutions to the problems of chain and pin wear are mainly based on materials,structures,wear-resistant coatings and special hot and cold treatment processes,but these technologies have short aging and increase the production cost of chains to a certain extent.Studies have shown that the surface texture technology can play an excellent friction-reducing and wear-resisting effect on the surface of friction pairs.Inspired,in this paper for the first time the surface texture technology is applied to Marine engine chain pin shaft wear and tear,through a large number of experimental study and numerical simulation analysis,the engine chain pin shaft surface texture of the manufacturing process and research on the friction wear properties of system,in order to face for a long time in the field of engine chain wear problem provides a new solution and theoretical basis.Firstly,the influence of laser processing parameters on the temperature field of surface texture processing was studied.The simulation software COMSOL Multiphysics was used to study the laser machining mechanism of surface texture.The temperature field of two typical surface textures(pits and grooves)in nanosecond laser machining process was numerically simulated to explore the influence of laser processing parameters on the temperature field of surface texture machining.The results show that laser processing of materials is a highly nonlinear unsteady heat transfer process,and materials are melted,evaporated or sublimated under the action of high energy density laser beam,so as to achieve removal.During laser processing,the temperature decreases gradually along the direction of spot diameter and material thickness,and the ha Z is smaller in the direction of spot diameter and larger in the direction of material thickness.Secondly,the laser processing experiment of surface texture of Marine engine chain pin shaft was carried out to further study the laser processing mechanism of surface texture.Based on single factor theory,the effect of laser processing parameters on surface texture was investigated.The results show that the optimal pit texture laser processing parameters are as follows: pulse number 5000,repetition frequency 2000 k Hz;The optimal laser processing parameters of groove texture are as follows: laser power 50 W,scanning speed 150mm/s,scanning times 150 times and repetition frequency 2000 k Hz.Then,the friction-reducing and wear-resisting properties and mechanism of surface texture of Marine engine chain pin shaft are studied.Laser process parameters optimization based on surface texture,using nanosecond laser processing out of the square,sine,round three shapes of surface texture,on the basis of a large number of friction and wear experiments,the effects of texture shape on the surface of tribological performance,the results showed that sine texture shows the optimal anti-friction wearresisting performance.Furthermore,the effects of sinusoidal texture on surface tribological properties were systematically studied.Combined with the analysis of surface friction coefficient and wear morphology,the optimal texture parameters were determined as follows: 30% area,400μm width,15μm depth,90° inclination Angle.It is proved that the friction-reducing and wear-resisting mechanisms of surface texture mainly include "secondary lubrication" effect,"local hydrodynamic lubrication" and "storage pool" effect.Finally,the effect of local fluid dynamic pressure lubrication on textured surface and the friction-reducing and wear-resisting mechanism were studied.Based on fluid simulation technology of ANSYS Fluent,the pressure distribution of oil film on textured surface was simulated when local fluid dynamic pressure lubrication was produced.Based on the single factor theory,the influence of surface texture parameters on oil film pressure was explored,and the friction-reducing and wear-resisting mechanism of surface texture was analyzed.The results show that when the texture is sinusoidal texture,15%area occupied,400μm width,15μm depth and 30° inclination Angle,the dynamic lubrication effect of local fluid produced on the texture surface is the strongest,and the bearing capacity of oil film is the largest.Through the study in this paper,it is confirmed that the friction-reducing and wearresisting characteristics of surface texture are the result of synergistic effect of multiple factors,and the research results in this paper provide a theoretical basis for solving the engine chain wear problem by using surface texture technology.