Electropolishing of 316L Stainless Steel Small-Diameter Tubes: Reduced Surface Roughness and Enhanced Corrosion Resistance

Semiconductor, pharmaceutical, and food processing industries require highly clean and corrosion-resistant 316L stainless steel pipelines to prevent product contamination and ensure durability. This study employs an optimized electropolishing technique for small-diameter 316L stainless steel tubes, aimed at significantly reducing surface roughness and enhancing corrosion resistance to meet stringent industry standards. A comprehensive examination of the effects of electropolishing parameters—polishing time, current density, and temperature—on surface roughness and morphology was conducted. Optimal conditions were determined to be 105 seconds of polishing time, a current density of 50 A·dm^-2, and a temperature of 60 °C. Under these conditions, the tube achieves a mirror-like finish with a surface roughness of 0.063 μm. Corrosion resistance was characterized using electrochemical testing and x-ray photoelectron spectroscopy. The electropolished tube exhibits superior corrosion resistance compared to the mechanically polished tube, which is attributed to its increased thickness and chromium-rich passive film.