Manufacturing of high-precision surface micro-structures on stainless steel by ultrasonic impact peening

Ultrasonic impact peening (UIP) is not only a mature technique of surface treatment, but also a promising method of surface texturing for promoting performance and functionalities of components and devices. In the present work, we demonstrate the feasibility of applying UIP in the manufacturing of high precision surface micro-structures on 316L stainless steel using a YG6 cemented carbide tool. Specifically, analytical investigation of material deformation map under UIP is carried out, which is validated by corresponding finite element simulations based on a combined nonlinear isotropic/kinematic hardening model, as well as experiments performed on home-made UIP apparatus. Finally, surface micro-structures of aligned grooves with a depth of 2 μm and a periodicity of 240 μm are fabricated by using UIP, and are subsequently subjected to linear reciprocating ball-disk sliding tests. Corresponding experimental results show that the micro-structures fabricated by UIP possess comparable accuracy of groove morphology and frictional properties with that fabricated by using ultrasonic elliptical vibration cutting using a single crystal diamond tool. The present work sheds lights on the fabrication of high precision surface micro-structures on ferrous metals by mature UIP technique.