| 摘要 |
PURPOSE:To efficiently pickle a hot-rolled steel by descaling the steel with a high-temp. pickling soln., and then releasing the formed smut with a low-temp. pickling soln. CONSTITUTION:When a hot-rolled steel (hot-rolled high-Mn steel, etc.) is descaled by pickling, the steel is pickled with a pickling soln. heated at >=30 deg.C until smut is formed on the steel surface. H2SO4 is preferably used as the acid at this time, and the temp. is appropriately controlled to about 60-80 deg.C and the concn. to about 0.1-0.6 N. The steel is then washed with water, and dried. The smut is released in a pickling soln. held at a temp. (0-30 deg.C) lower than 30 deg.C and >=10 deg.C lower than the primary pickling temp. By this method, descaling and smut removal can be performed without any mechanical means, and a hot-dipped steel is economically produced. |
