METHOD OF MANUFACTURING HIGH Si-CONTAINING HIGH TENSILE STRENGTH STEEL SHEET EXCELLENT IN CHEMICAL CONVERSION TREATMENT PROPERTY

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a high Si-containing high tensile strength steel sheet excellent in a chemical conversion treatment property.;SOLUTION: When manufacturing a high tensile strength steel sheet by executing cold rolling and continuous annealing to a steel sheet having a composition containing, by mass, 0.03% or more and 0.20% or less of C, 0.5% or more and 1.8% or less of Si, 1.5% or more and 3.5% or less of Mn, 0.01% or more and 0.04% or less of P, 0.001% or more and 0.01% or less of S, and the balance comprising Fe and inevitable impurities, brush grinding of a grinding amount equal to or larger than 0.5 g/m² and smaller than 1.0 g/m² is executed to the surface of the steel sheet after the continuous annealing, and then hydrochloric acid pickling is executed using hydrochloric acid whose concentration is over 1.0% and below 3.0%.;COPYRIGHT: (C)2012,JPO&INPIT