| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a high-tensile cold rolled steel strip containing high Si which has tension strength 590 MPa or more and is excellent in a chemical conversion treatment property. <P>SOLUTION: Steel material having a composition containing 0.03-0.20% of C, 0.5-1.8% of Si, 1.5-3.5% of Mn, 0.1% or less of P, 0.01% or less of S, 0.02-0.1% of Al, 0.005% or less of N by mass%, is subjected to a hot-rolling process wherein the steel material is hot-rolled including rough-rolling and finish-rolling, and is wound at 540-640°C. Then, the steel material is subjected to a pickling process of pickling with an amount of resolution 80-200 g/m<SP POS="POST">2</SP>. Furthermore, a cold rolling process, an annealing process, and a pickling process after the annealing process are sequentially conducted. Through these processes, a grain-boundary corrosion layer on a surface and an oxide thickened layer are removed, and the high-tensile cold rolled steel strip containing high Si which is excellent in a cold-rolling property, and excellent in the chemical conversion treatment property and coating adhesiveness, can be easily and stably manufactured. <P>COPYRIGHT: (C)2013,JPO&INPIT |
