Electrochemical polishing of selected stainless steels

The AISI 316Ti (EN 1.4571) austenitic stainless steel sample (50 × 30 × 1,5 mm) was used for the study. The main elements forming the steel are: chromium (16-18%), molybdenum (2.0-3.0%), nickel (10.0-14.0%), titanium (max 0.7%), and iron as the rest of the steel composition. The electrolytic polishing operations were performed at the current density of 50 A/dm2. The main elements of the electropolishing setup were a processing cell, a DC power supply RNG-3010, the electrodes and connecting wiring. The studies were carried out in the electrolyte of initial temperature of 50±5 °C. For the studies, as the electrolyte a mixture of two acids, i.e. H3PO4:H2SO4 equal to 60%:40%, was used. For surface characterization the 3D roughness parameters(Sa=0.744 μm, Sq=0.984; Sp=2.32, Sv=3.5, St=5.88; Ssk=–0.898; Sku=2.97) regarding ISO25178 were used.