Laser Surface Texturing And The Study Of Friction And Wear Properties Of 304 Stainless Steel

Introducing specific textures on a tribological surface can contribute to friction reduction in sliding contacts.Laser surface texturing is a kind of efficient and controllable method for producing the texture of micro-pores. However, due to the high intensity of the laser beam pulse, surface area in close proximity to the dimple also undergoes melting and rapid resolidification. This collateral damage of the surface is unavoidable when using a high power laser surface processing, leading to an increased roughness around the holes. So far, however, little attention was paid to the bulges around the dimples rim and their influence on the friction and wear behavior, thus there are fewer studies on that. Therefore, it is crucial to investigate the effects of different laser parameters on the morphology and size of the micro-pores and understand the role of bulges in the tribological performance.The research status, development trend and numerical simulation of laser surface texturing techniques are introduced in this paper. At the same time, physical phenomena involved in the process and its impact on the morphology of the micro-pores are analysed. Furthermore, a numerical simulation of pulsed laser ablation crater are modeled and verified experimentally verified. The detaied research contonts are as follows:Firstly, the physical principle of laser surface texturing is explained detailedly. Effects of recoil pressure, surface tension, and the auxiliary gas on dynamics of molten metal are analyzed. Taking all the related factors into consideration, a simulation model of pulsed laser ablation crater of 304 stainless steel is built based on the physical principle. Much emphasis is placed on the effects of pulse numbers and pulse energy on the morphology and size of the crater.The experiment of laser surface texturing is conducted. Using the control variable method, the effects of pulse energy, pulse number, pulse frequency, and auxiliary gas on the topography and size respectively. Combining the role of recoil pressure with the role of surface tension in the Marangoni flow, the reasons for changes in morphology and size are described. And machining optimization of laser surface texturing can be achieved by such desings.Friction and wear experiment of 304 stainless steel samples processed by laser surface texuring is carried out. The tribological behavior of untexured sample, texured sample, and texured-lapped sample is investigated respectively under different working conditions.Much emphasis is put on the texured sample for further sduty and the role of bulges in the tribological performance is analysed. Furthermore, the wear observation is also conducted.Finally, the paper summarizes all the done work and views the study direction in the future.