Resistance spot welded joint and a process for producing a resistance spot welded joint
US12428692B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2022 |
| Grant date | Sep 30, 2025 |
| Priority date | — |
| Expiry date | Dec 5, 2043 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/32
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A cold-rolled and heat-treated steel sheet, having a composition comprising, by weight percent: 0.10%≤C≤0.40%, 3.5%≤Mn≤8.0%, 0.5%≤Si≤2.5%, 0.003%≤Al≤3.0%, with Si+Al≥0.8%, 0.001%≤Mo≤0.5%, S≤0.010%, P≤0.020%, N≤0.008%, and optionally one or more elements selected from amongst Cr, Ti, Nb, V and B, such that: 0.01%≤Cr≤2.0%, 0.010%≤Ti≤0.080%, 0.010%≤Nb≤0.080%, 0.010%≤V≤0.30%, 0.0005%≤B≤0.003%, A remainder of the composition being iron and unavoidable impurities resulting from the smelting. The microstructure consists of, in surface fraction, between 10% and 50% of retained austenite, at most 8% of fresh martensite, and tempered martensite. The retained austenite comprises Mn-enriched austenite, having a Mn content higher than 1.3*Mn %, Mn % designating the Mn content of the steel sheet, the surface fraction of said Mn-enriched austenite with respect to the whole microstructure being comprised between 2% and 12%; and Mn-poor austenite, having a Mn content comprised between 0.5*Mn % and 1.3*Mn %.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.