| 摘要 |
PROBLEM TO BE SOLVED: To shorten the time required for replacing an acid pickling solution on changing a steel type, and to reduce an amount of the waste water containing hazardous chromium, when acid pickling both common steel and stainless steel with hydrochloric acid using one pickling facility. SOLUTION: A method for acid pickling a stainless steel sheet by using a continuous acid pickling facility for both common steel and stainless steel, which arranges several pickling tanks in series, includes acid pickling by using a pickling solution of hydrochloric acid with concentration of 60 g/l or less, at a solution temperature of 40 deg.C or more and less than 65 deg.C, in at least one of the pickling tanks in upstream of the above continuous pickling facility, and by using the pickling solution of hydrochloric acid with concentration satisfying the expression -(10/4)T+300<=C<=-(10/4)T+475 (wherein T is the solution temperature ( deg.C) and C is the concentration of hydrochloric acid (g/l).), at the solution temperature of 65 deg.C or more and 90 deg.C or less, in the rest of the other pickling tanks in downstream side.
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