| 摘要 |
The present invention provides high burring, high strength steel sheet excellent in softening resistance of the weld heat affected zone and a method of production of the same, that is, high burring, high strength steel sheet excellent in softening resistance of the weld heat affected zone containing, by wt%, C: 0.01 to 0.1%, Si: 0.01 to 2%, Mn: 0.05 to 3%, P<=0.1%, S<=0.03%, Al: 0.005 to 1%, N: 0.0005 to 0.005%, and Ti: 0.05 to 0.5% and further containing C, S, N, Ti, Cr, and Mo in ranges satisfying 0% < C-(12/48Ti-12/14N-12/32S) <=0.05%, Mo+Cr>=0.2%, Cr:50.<=%, and Mo<=0.5%, the balance being Fe and unavoidable impurities, wherein the microstructure comprises ferrite or ferrite and bainite.
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