Influence of laser-mechanical treatment on surface topography, erosive wear and contact stiffness

This paper presents the study of surface topography, erosive wear and contact stiffness after the new hybrid method has been applied for the modification of steel surface layer. A combination of laser alloying and the burnishing process, both performed in laser set up, was proposed in order to reduce surface roughness being formed during laser treatment, and to improve contact stiffness. The experiments were conducted on stainless steel, alloyed with Stellite 6, and simultaneously burnished in hot and cold conditions in one operation. The alloying process was performed with continuous laser CO2 at different parameters. The influence of hybrid treatment parameters on surface topography was examined. This hybrid treatment reconstructed the surface topography and caused an increase in surface smoothness compared to laser alloying. More than a threefold decrease in the average level of roughness, Sa, due to the burnishing process was stated. A good correlation between the parameters of hybrid treatment and roughness was demonstrated. The study shows that laser-mechanical treatment improves erosive wear and contact stiffness compared to laser alloyed and thermal sprayed Stellite 6 layers.

► The new surface treatment combining the laser alloying with the dynamic burnishing was studied.
► The application of the new head allowed for simultaneous hot and cold work and provided high intensity of the burnishing.
► The burnishing process decreased the heights of roughness.
► A good correlation between the parameters of hybrid treatment and surface roughness was stated.
► The hybrid treatment improved the erosive wear resistance and the contact stiffness.