HIGH-STRENGTH STEEL THIN SHEET SUPERIOR IN HOLE-EXPANDABILITY AND DUCTILITY,申请号JP20030357280-传众专利搜索

HIGH-STRENGTH STEEL THIN SHEET SUPERIOR IN HOLE-EXPANDABILITY AND DUCTILITY

申请公布号：JP2005120437(A)

申请号：JP20030357280

申请日期：2003.10.17

申请公布日期：2005.05.12

申请人：

NIPPON STEEL CORP

发明人：OKAMOTO TSUTOMU;TANIGUCHI YUICHI;FUKUDA SHUJI

分类号：C22C38/00;C22C38/14;C22C38/58;(IPC1-7):C22C38/00

主分类号：C22C38/00

摘要：PROBLEM TO BE SOLVED: To provide a high-strength steel sheet superior in hole-expandability and ductility with a tensile strength of 980 N/mm<SP>2</SP>or higher. SOLUTION: The high-strength steel sheet superior in hole-expandability and ductility comprises, by mass%, 0.01-0.20% C, 1.5% or less Si, 1.5% or less Al, 0.5-3.5% Mn, 0.2% or less P, 0.0005-0.009% S, 0.009% or less N, 0.0006-0.01% Mg, 0.005% or less O, one or two of 0.01-0.20% Ti and 0.01-0.10% Nb, and the balance iron with unavoidable impurities, and satisfies all of the following three expressions: [Mg%]≥([O%]/16×0.8)×24 --- (1), [S%]≤([Mg%]/24-[O%]/16×0.8+0.00012)×32 --- (2), and [S%]≤0.0075/[Mn%] --- (3); and has a metallographic structure consisting mainly of a bainite phase. COPYRIGHT: (C)2005,JPO&NCIPI