Investigating the effect of laser shock peening on the wear behaviour of selective laser melted 316L stainless steel

Selective Laser Melting (SLM) is an emerging additive manufacturing technology that produces metallic parts with high customization. The applications of stainless steel 316L have been restricted owing to their poor tribological performance, especially in the as-printed condition. In this study, SLM-made SS 316L is subjected to laser shock peening (LSP), one of the surface modification techniques, to improve its characteristic micro-structure, mechanical and wear behaviour. X-ray diffraction and residual stress analysis show that the laser shock peening promotes micro-level grain refinement and compressive residual stresses in the severely deformed layer, resulting in increased micro-hardness up to 22%. Pin on disk wear test is carried out, and the optimum condition is determined using the Taguchi method for the polished as-printed specimen. The wear rate of polished as -printed and laser shock peened specimens at optimized conditions were 2.4156 x 10-3 mm3 m-1 and 1.7871 x 10-3 mm3 m- 1, respectively. The laser shock peened specimen showed higher wear resistance with a 26% reduction in wear rate compared to the polished as-printed specimens.

Automated summary

Selective Laser Melting (SLM) is an emerging additive manufacturing technology that allows highly customized metallic parts. However, the poor tribological performance of stainless steel 316L in the as-printed condition limits its applications. This study applies laser shock peening (LSP), a surface modification technique, to SLM-made SS 316L to improve its micro-structure, mechanical properties, and wear behavior. Results show that LSP promotes micro-level grain refinement and compressive residual stresses, resulting in increased micro-hardness and enhanced wear resistance.