High strength hot-rolled steel sheet having excellent ductility, stretch flangeability and uniformity and method of manufacturing the same
US9657380B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2012 |
| Grant date | May 23, 2017 |
| Priority date | — |
| Expiry date | Jan 12, 2033 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A slab has a steel composition including 0.020% to 0.065% of C, 0.1% or less of Si, 0.40% to less than 0.80% of Mn, 0.030% or less of P, 0.005% or less of S, 0.08% to 0.16% of Ti, 0.005% to 0.1% of Al, 0.005% or less of N, and the balance being Fe and incidental impurities, in which Ti*(=Ti−(48/14)×N) satisfies [Ti*≧0.08] and [0.300≦C/Ti*≦0.375], is subjected to hot rolling to obtain a hot-rolled steel sheet in which the steel microstructure includes, in terms of area fraction, 95% or more of a ferrite phase; the average ferrite grain size is 10 μm or less; the average grain size of Ti carbides precipitated in steel is 10 nm or less; and Ti in the amount of 80% or more of Ti* is precipitated as Ti carbides.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.