High-strength cold rolled steel sheet and method for manufacturing same
US11459647B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 2018 |
| Grant date | Oct 4, 2022 |
| Priority date | — |
| Expiry date | Dec 13, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided are a high-strength cold rolled steel sheet that has a tensile strength of 980 MPa or more, excellent ductility, and a low failure rate in a hole expanding test, and a method for manufacturing the same. A high-strength cold rolled steel sheet comprises a predetermined composition, wherein a total area ratio of ferrite and bainitic ferrite is 20% to 80%, an area ratio of retained austenite (RA) is more than 10% and 40% or less, an area ratio of tempered martensite is more than 0% and 50% or less, a ratio of RA with an aspect ratio of 0.5 or less is 75% or more, a ratio of RA with an aspect ratio of 0.5 or less in ferrite grain boundaries is 50% or more, and an average KAM value of bcc phase is 1° or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.