Abstract
Surface Cr‐depletion beneath the oxide scale in heat‐treated stainless steels plays a determining role in both functions of acid pickling which are: (i) scale detachment or descaling proper and (ii) restoration at the metal surface of the base Cr content, i.e. of the highest passivity properties. As the anodic behavior of the impoverished alloy is quite different from that of the base alloy, definite advantages may be obtained by potentiostatically polarizing the steel during pickling in a potential range where the anodic dissolution of the Cr‐depleted alloy is kinetically favored over that of the base alloy. Experimental evidence is given for AISI Type 304 steel in both 
and simple 
baths, showing the attractiveness of potentiostatic pickling in allowing the replacement of the usual nitric‐hydrofluoric acid pickles with less toxic and cheaper sulfuric baths.