High Speed Pickling Process for Improving Corrosion Resistance of Austenitic Stainless Cold Strip

摘要

The present invention relates to a method of pickling the surface of a steel plate at high speed when the austenitic cold-rolled stainless steel plate requiring surface quality is manufactured and more specifically, to a method of pickling a high-chrome austenitic cold-rolled stainless steel plate capable of pickling the austenitic cold-rolled stainless steel plate containing 16% or more of chrome. The method of pickling a high-chrome austenitic cold-rolled stainless steel plate at high speed comprises: a neutral salt electrolyzing step of electrolyzing and removing chrome-rich scale from the surface of the steel plate using an electrolyte solution which uses sodium sulfate as an electrolyte; a sulfuric acid electrolyzing step of electrolyzing and removing iron-rich scale using an electrolyte solution which uses sulfuric acid as the electrolyte; and a mixed acid dipping step of dipping the cold-rolled steel plate in a mixed acid solution containing sulfuric acid, hydrofluoric acid, and hydrogen peroxide; wherein the whole pickling process is completed within 45-240 seconds. When the austenitic cold-rolled stainless steel plate is pickled, the present invention does not use nitrogen; thereby reducing the installation burden of a de-NOx system. Furthermore, the present invention is appropriate to high-speed production because it can be easily controlled by controlling the pickling process depending on the concentration of the hydrogen peroxide and the hydrofluoric acid and can produce an austenitic cold-rolled stainless steel plate of high quality because the quality after the pickling process is improved more than the existing pickling process.