HIGH SPEED PICKLING METHOD FOR SURFACE IMPROVEMENT OF HIGH CHROMIUM FERRITIC STAINLESS COLD STEEL STRIP

摘要

The present invention relates to a method for pickling high chrome and ferrite-based stainless steel. More specifically provided is the method for pickling high chrome and ferrite-based stainless steel comprising: an electrolytic pickling step for neutral salt electrolytic pickling and sulfuric acid electrolytic pickling a high chrome and ferrite-based stainless cold-rolled steel plate containing 17-26 wt% of chrome; and a mixed-acid immersion step for immersing the cold-rolled steel plate on which the electrolytic pickling has been performed, in a mixed-acid solution containing sulfuric acid and hydrofluoric acid. The electrolytic pickling step is conducted by controlling an applied current amount according to the annealing temperature. The mixed-acid immersion step is processed by controlling the content amount of free hydrofluoric acid (Free HF) included in the mixed-acid solution according to grades of steel and controlling the oxidation-reduction potential (ORP).