Method for producing high-strength steel parts with improved ductility, and parts obtained by said method
US11473166B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2018 |
| Grant date | Oct 18, 2022 |
| Priority date | — |
| Expiry date | Nov 17, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A rolled steel sheet, for press hardening is provided, having a chemical composition where Ti/N>3.42, and the carbon, manganese, chromium and silicon contents satisfy: The sheet has a nickel content Nisurf at any point of the steel in the vicinity of the surface over a depth Δ, such that: Nisurf >Ninom, Ninom denoting the nominal nickel content of the steel, and such that, Nimax denoting the maximum nickel content within Δ: and such that: and the surface density of all of the particles Di and the surface density of the particles D(>2 μm) larger than 2 micrometers satisfy, at least to a depth of 100 micrometers in the vicinity of the surface of said sheet: Di+6.75 D(>2 μm) <270 Di and D(>2 μm) being expressed as number of particles per square millimeter, and said particles denoting all the oxides, sulfides, and nitrides, either pure or combined such as oxysulfides and carbonitrides, present in the steel matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.