Electropolishing attacks and removes oxides and the corrosion prone chromium depleted layer. During the process, electropolishing can also leave a smoother surface, further improving corrosion resistance. The selective cleaning and reduced roughness leaves optimal corrosion resistance.
Electropolishing can be accomplished through a dip process on small parts, or through local cleaning on large parts called acid washing. Because most large welded parts are too large to fit into an electropolishing tank, local cleaning of welded areas is often used. This fully repairs the welded areas, but doesn't decontaminate the entire surface of the product.