METHOD OF CLEAN ACID CLEANSING OF FERRITE STAINLESS STEEL

摘要

PURPOSE: A clean acid cleansing method of ferrite stainless steel is provided to clean a ferrite stainless steel by using only a sulfuric acid tub without using a mixed acid tub causing environmental pollution due to generation of NOx. CONSTITUTION: A portion of scales on a steel sheet passing through an annealing blaster or a shot blaster is removed mechanically by using a device(18) such as a grinding brush. To eliminate generation of NOx due to use of a mixed acid tub originally, 15-25g/l of Fe(NO3)3*9H2O is added to perform as a mixed acid tub in a sulfuric acid tub(4) and to secure the speed of a general acid cleansing. The acid cleansing is performed under the condition of the temperature of the sulfuric acid tub is 90-100°C and the concentration is 150-200g/l. By performing acid cleansing by using only the sulfuric acid tub, the concentration is set up higher than a general cleansing method. The amount of metal molten in a solution is reduced and the use amount of acid is reduced thereby.