Hammer peening technology-the past, present, and future

A number of surface modification processes have been developed over the past decades. Depending on the application in industry, different processes are selected to meet the needs. Shot peening is one of the widely adopted surface modification processes in various industries dedicated for improving the material properties. On the other hand, hammer peening is an emerging and promising surface modification process that can provide wide range of benefits, encompassing fatigue life enhancement, surface finish improvement and texturing, microstructural refinement, corrosion, and wear resistance. This technology has been extensively studied on its application as a post-welding treatment on metal alloys. However, there is limited information available for other applications such as additive manufacturing. This paper discusses how hammer peening has evolved into its current state today and the role it played in various industries. The variants of hammer peening technology and the standardized key process parameters are elucidated. In view of the rigorous research and development, the current state-of-the-art on different applications area also represented. Despite the proven capability by many studies, the gaps to the industrialization of this technology still exist which are identified in the final section of the paper.