Pulse Electrochemical Polishing of 304 Stainless Steel: Interactive Effects of Bath Temperature, Pulse Duty Ratio, Polishing Time, and Current Density on Surface Reflectivity and Morphology

Abstract

304 stainless steel is deemed an indispensable material in the industry. In many instances, the surface of the production equipment needs to be treated for low-corrosion passivation, lower surface roughness, good degree of finish and cleanliness. The process characteristics of pulse electrochemical polishing meet these requirements well. The current study investigates the effects of the major processing parameters on the surface reflectivity and the surface metallography. The electrolyte with 29.4% water content and a ratio between H2SO4and H3PO4of 2 and 4 has been proven to be successful, showing no corrosion pitting points on the specimen surface. The electrolyte temperature of 50~55°C, the pulse duty ratio of 33~50% and the electrical current density of 50 to 55A/dm2are found to be optimal. The addition of 2.4% glycerin and 2.2% glucose provides a very fine surface, surface reflectivity of stainless steel from 18% improve 89%.