Pickle Passivation of Stainless Steel. Pickling is the removal of any type of high temperature related scale such as heat treatment or weld burn. Wherever stainless steel has been heated by welding, heat treating or any other means to the point where a multi colored oxide layer can be seen on the surface of the stainless, there is a chromium depleted layer on the surface of the stainless steel below the oxide layer. The lower chromium content of course gives lower corrosion resistance. Pickle Passivation is the answer to restore the best corrosion resistive performance. In order to do this the damaged metal layer must be removed, exposing the fully alloyed stainless surface.If you choose to mechanically remove this layer it may leave abrasives or other foreign particles imbedded in the surface of the stainless material. Chemical removal is the best solution to this problem. Central Electropolishing can help you decide the best means of removal of this infective discoloration, whether it be employing a Nitric Acid Bath or use of a specially formulated pickling paste. The bottom line is we are ready and able to help you with this unsightly potentially corrosive situation.