METHOD FOR PICKLING HOT ROLLED STEEL SHEET HAVING ADVANCED HIGH STRENGTH

摘要

PURPOSE: A method for pickling a high-tension hot-rolled steel sheet is provided to prevent over-pickling generating damages in a base metal by limiting the including quantity of hydrochloric acid lower than 5wt.%. CONSTITUTION: A method for pickling a high-tension hot-rolled steel sheet(1) is as follows. A high-tension hot-rolled steel sheet passes through hydrochloric acid solution of acid tanks(2, 3, 4) for removing scales and the hot-rolled steel is rinsed in rinsing tanks(6, 7, 8). The high-tension hot-rolled steel sheet includes Si(Silicon) and Mn(Manganese). A mixed acid solution including 1 to 5wt.% hydrochloric acid and 2 to 10wt.% hydrofluoric acid and the residual Si and Mn compound that are not removed in an acid tanks is removed by the acid compound.