High-yield-ratio and high-strength thin steel sheet superior in weldability and ductility, high-yield-ratio high-strength hot-dip galvanized thin steel sheet, high-yield ratio high-strength hot-dip galvannealed thin steel sheet, and methods of production of same
US8084143B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2004 |
| Grant date | Dec 27, 2011 |
| Priority date | — |
| Expiry date | Dec 4, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12799
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
High yield ratio high-strength thin steel sheet superior in weldability and ductility characterized by: being comprised of steel containing, by mass %, C: over 0.030 to less than 0.10%, Si: 0.30 to 0.80%, Mn: 1.7 to 3.2%, P: 0.001 to 0.02%, S: 0.0001 to 0.006%, Al: 0.060% or less, N: 0.0001 to 0.0070%, containing further Ti: 0.01 to 0.055%, Nb: 0.012 to 0.055%, Mo: 0.07 to 0.55%, B: 0.0005 to 0.0040%, and simultaneously satisfying 1.1 ≦14×Ti(%)+20×Nb(%)+3×Mo(%)+300×B(%)≦3.7, the balance comprised or iron and unavoidable impurities, and having a yield ratio of 0.64 to less than 0.92, a TS×E11/2 of 3320 or more, an YR×TS×EL1/2 of 2320 or more, and a maximum tensile strength (TS) of 780 MPa or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.