High-strength steel sheet and method for manufacturing same
US10711333B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2015 |
| Grant date | Jul 14, 2020 |
| Priority date | — |
| Expiry date | Jun 15, 2037 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB32B2255/205
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed is a steel sheet having a predetermined chemical composition and a steel microstructure that contains, in area ratio, 15% or more and 55% or less of polygonal ferrite and 15% or more and 30% or less of martensite, and that contains, in volume fraction, 12% or more of retained austenite, in which the polygonal ferrite, the martensite, and the retained austenite have a mean grain size of 4 μm or less, 2 μm or less, and 2 μm or less, respectively, and each have a mean grain aspect ratio of 2.0 or less, and in which a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.