HOT-BAND ANNEALING EQUIPMENT, HOT-BAND ANNEALING METHOD AND DESCALING METHOD FOR SI-CONTAINING HOT ROLLED STEEL SHEET

摘要

Provided is a hot-band annealing method comprising subjecting a Si-containing hot rolled steel sheet, having an oxidized scale formed on a surface of the steel sheet by hot rolling, to hot-band annealing with a hot-band annealing equipment provided with a heating zone, a soaking zone, a cooling zone, and a rapid heating device at an upstream side of the heating zone and/or in an inlet side of the heating zone, wherein the hot rolled steel sheet is heated by not lower than 50° C. at a heating rate of not less than 15° C./s by using the rapid heating device to improve a descaling property. Also, provided is a descaling method characterized by subjecting the Si-containing hot rolled steel sheet, after the hot-band annealing, to descaling only by pickling without requiring mechanical descaling or heating the steel sheet in the pickling process.