Hot-stamped steel, cold-rolled steel sheet and method for producing hot-stamped steel
US10544475B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2014 |
| Grant date | Jan 28, 2020 |
| Priority date | — |
| Expiry date | Jan 13, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A hot-stamped steel according to the present invention has a predetermined chemical composition, satisfies (5×[Si]+[Mn])/[C]>10 when [C] is the amount of C by mass %, [Si] is the amount of Si by mass %, and [Mn] is the amount of Mn by mass %, includes 40% to 95% ferrite and 5% to 60% martensite in area fraction, and optionally further includes 10% or less pearlite in area fraction, 5% or less retained austenite in volume fraction, and less than 40% bainite in area fraction. The total of the area fraction of ferrite and the area fraction of martensite is 60% or more, the hardness of martensite measured with a nanoindenter satisfies H2/H1<1.10 and σHM<20, and TS×λ which is product of tensile strength TS and hole expansion ratio λ is 50000 MPa·% or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.