| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an Si-containing hot rolled steel sheet excellent in corrosion resistance after coating as well as chemical conversion treatment properties, to provide a method for advantageously manufacturing the same, and to provide an automobile member using the Si-containing hot-rolled steel sheet. <P>SOLUTION: A steel sheet after hot rolling, which includes 0.5-3.0 mass% of Si, preferably, which further includes C: 0.01-0.30 mass%, Mn: 1.0-7.5 mass%, P: 0.05 mass% or less, S: 0.01 mass% or less and Al: 0.06 mass% or less, is pickled to remove an Si-containing oxide layer on the surface of the steel sheet, and then re-pickled using a non-oxidizing acid, preferably, any acid of hydrochloric acid with concentration of 0.1-50 g/L, sulfuric acid with 0.1-150 g/L, and a mixture of hydrochloric acid with 0.1-20 g/L and sulfuric acid with 0.1-60 g/L to reduce the surface coverage of an iron-based oxide on the surface of the steel plate to 40% or less. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
