High strength hot rolled steel plate excellent in enlargeability and ductility and method for producing thereof
US7615126B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2001 |
| Grant date | Nov 10, 2009 |
| Priority date | — |
| Expiry date | Mar 20, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
High strength, hot rolled steel plate providing high level of bore expandability and high level of ductility. Also, method of manufacturing same. In first aspect, steel plate comprises steel having, by mass, C:0.01-0.15%; Si:0.30-2.00%; Mn:0.50-3.00%; P≦0.03%; S≦0.005%; Ti:0.01-0.50%; and/or Ni:0.01-0.05%, with balance Fe and unavoidable impurities. In this steel, ≧80% of all grains have ratio of minor axis to major axis of ≧0.1. This steel plate has steel structure comprising ≧80% ferrite and balance bainite. In second aspect, steel plate has above composition, and ferrite-bainite duplex steel structure in which proportion of ferrite having grain diameter ≦2 μm is ≧80%. In third aspect, steel plate has above composition. wherein contents of C, Si, Mn, Ti, and Nb satisfy requirement represented by formula: 115 ≦(917−480[C %]+100[Si %]−100[Mn %])−(790×([Ti %]+[Nb %]/2)0.05)≦235. This steel plate has steel structure comprising ≧80% ferrite and balance bainite.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.