PICKLING METHOD FOR HIGH Si HIGH Mn-CONTAINING HOT ROLLED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a pickling method allowing for rapid removal of particle boundary oxidation layer generating just below a scale layer of a hot rolled steel sheet when winding a high Si high Mn-containing steel at high temperature of 550°C or more after hot rolling.;SOLUTION: There is provided the pickling method for a hot rolled steel sheet formed by hot rolling a steel containing Si:1.0% or more and Mn:1.5% or more by mass% and winding it at a temperature of 550°C or more, and the method has such a gist that the hot rolled steel sheet is subjected to pickling while a pickling condition is controlled so as to satisfy the following formula (1), then a particle boundary oxidation layer remaining on a surface of the hot rolled steel sheet is removed by adding physical force to the hot rolled steel sheet surface. (W-Ws)/(W0-Ws)≥0.3...(1), where W is pickling weight loss of the hot rolled steel sheet (g/m²), Ws is pickling weight loss of the hot rolled steel sheet needed for removing a scale layer (g/m²), W0 is pickling weight loss of the hot rolled steel sheet needed for removing the scale layer and the particle boundary oxidation layer (g/m²).;SELECTED DRAWING: Figure 3B;COPYRIGHT: (C)2017,JPO&INPIT