ENVIRONMENTAL-FRIENDLY AND HIGH SPEED PICKLING PROCESS FOR FERRITIC STAINLESS COLD STRIP WITH GOOD SURFACE QUALITY

摘要

PURPOSE: An environment-friendly high speed pickling process for manufacturing a low chrome ferrite-based stainless cold rolled steel plate with a superior surface quality is provided to reduce installation costs for a NOx removal facility and denitrification equipment and not to discharge the NOx and nitrate nitrogen because a nitric acid is not included in a mixed solution. CONSTITUTION: An environment-friendly high speed pickling process for manufacturing a low chrome ferrite-based stainless cold rolled steel plate comprises next steps. A cold rooled plate is dipped in the mixed solution containing a hydrogen peroxide so that a pickling process is performed. The mixed solution contains a sulfuric acid 70~200g/l and a free hydrofluoric acid 1~10g/l. An initial mixed acid solution comprises the hydrogen peroxide concentration 7g/l or greater. The mixed acid solution has a pickling speed of 3 to 15g/m^2min The sillicon oxide is eliminated from a low chrome ferrite-based stainless cold rolled steel plate containing the chrome below 14% by using the mixed solution in which a nitric acid is not included.