Research on surface integrity of ultrasonic vibration polishing for laser-clad 316L stainless steel

Abstract 316L stainless steel is widely valued for its excellent formability and good corrosion resistance, yet its relatively low yield strength limits its use in high-performance applications. While laser additive manufacturing (LAM) can enhance the mechanical properties of 316L stainless steel, facilitating its application in demanding sectors such as aerospace and energy, a significant challenge persists: LAM-produced parts inherently suffer from high surface roughness, necessitating effective secondary finishing. This study addresses this critical post-processing gap by introducing and systematically optimizing Ultrasonic Vibration Polishing (UVP) as a novel finishing solution specifically for additively manufactured 316L stainless steel. The research methodically investigates the individual and combined effects of key UVP parameters—including ultrasonic amplitude, abrasive particle size, spindle speed, and applied pressure—on final surface quality. The primary finding reveals that an optimized parameter set (ultrasonic amplitude of 6 μm, abrasive particle diameter of 0.5 μm, spindle speed of 5000 rpm, and initial pressure of 24 N) achieves a dramatic reduction in surface roughness, from an initial 1837 nm to below 42 nm. This represents a reduction by a factor of over 43, transforming the surface from an as-built state to a precision-machined quality. The practical significance of this work is substantial: it provides a validated and highly effective post-processing strategy that directly enables the integration of high-strength additively manufactured 316L stainless steel components into advanced, precision-critical products, thereby broadening its functional application scope beyond current limitations.