Influence Of Magnetic Field On Tribological Performance Of Laser Dimples Textured Surface

The tribological performances of laser dimple textured surface can be improved.More and more friction pairs are used in magnetic field with the extensive engineering application of magnetic technology.Therefore,it is necessary to explore the influence of magnetic field on the tribological properties of ferromagnetic materials.In this paper,laser welding machine is used to process laser dimple textured surface on the 45~#steel sample.The dry friction and wear tests of the laser dimples texture specimens were carried out under three experimental conditions,common,degaussing and additional magnetic conditions respectively.The coefficient of friction,wear and hardness of dimple edge were measured.The worn surfaces of laser dimple textures were observed,and element contents of wear debris were analyzed.Wear debris within laser textured dimples was observed at regular intervals to analyze trapping processes.An anti-leakage device under oil-rich lubricating experimental conditions was designed,and the Strebeck curve of the surface of the test piece under normal conditions and applied magnetic field conditions was drawn.The change of the viscosity value of the lubricating oil before and after wear was measured,and the fluid dynamic pressure was analyzed.The phenomenon of wear debris limiting dislocation migration,reducing plastic deformation and protecting the substrate.Under the dry friction and wear test conditions,the applied magnetic field and degaussing conditions,the friction coefficients and the wear mass loss on the textured surface are lower than common conditions.Before the value of the applied magnetic field strength reaches the saturation value,with the increase of magnetic field strength,the friction coefficient and wear mass loss on the textured surfaces,and when the magnetic field strength exceeds the saturation value,the decrease range decreases.The experimental results show that both degaussing and additional magnetic conditions can reduce abrasive wear of laser textured surface,and the coefficient of friction and wear are decreased.With additional magnetic condition,the uniform debris attachment to inner walls of laser textured dimples occurs.The distributions of magnetic domains within specimens have influence on the trapping processes of wear debris during wear experiments.There exist phenomena of hardness improvement of dimple edge,oxidation of wear debris and coverage of wear debris on worn surface under additional magnetic condition.Under the experimental conditions of oil-rich lubrication and wear,the friction coefficient of the dimple textured surface under the condition of applied magnetic field is significantly lower than that of common conditions.The test results show that:The applied magnetic field and dimple textured surface can help reduce the friction coefficient of the worn surface and improve the wear performance of specimen;the synergy of the two has a good anti-friction effect.The existence of the dimples textured surface can produce an asymmetrical oil pressure distribution,which generates additional fluid dynamic pressure effect,which promotes the friction pair to enter the fluid lubrication state in advance.The condition of applied magnetic field makes the abrasive debris particles dispersed in the lubricating oil,which increases the viscosity of the lubricating oil and expands the fluid dynamic pressure lubrication area.