Two-steps electrochemical polishing of laser powder bed fusion 316l stainless steel

Laser Powder Bed Fusion fabricated 316L stainless steel test components were electrochemically polished in a non-aqueous electrolytic solution consisting of 1M sodium chloride, ethylene glycol, and 10% ethanol, and in an aqueous commercial electrolyte A2. The influence of the high current densities ranging between 250 and 2000 mA/cm2 on the surface roughness (Psa, Wsa and Ssa), materials removal weight and thickness reduction with various morphological characteristics were investigated. It is confirmed that polishing at the tranpassive region was feasible in non-aqueous electrolytes where little pitting occurred. A two-step electrochemical process was proposed based on the characterisations to enhance the polishing effect, which consisted of two processes with different electrolytes and current densities. The experimental results indicated that the surface roughness of two-step polished steels with 1500 and 250 mA/cm2 current densities was reduced by 11.25% than the optimum result of the one-step EP with the non-aqueous electrolyte solution. The weight and thickness reduction were reduced by 3.39% and 9.02%, respectively, more than the optimum results of the one-step EP with the aqueous commercial electrolyte.