Galvannealed steel sheet and production method thereof
US10815553B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2016 |
| Grant date | Oct 27, 2020 |
| Priority date | — |
| Expiry date | Jun 30, 2037 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12965
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided is a galvannealed steel sheet having high strength and excellent deep drawability, and being further excellent in slab cracking resistance and secondary working embrittlement resistance. A base metal steel sheet of the galvannealed steel sheet has a chemical composition containing, in mass %: C: 0.0080% or less; Si: 0.7% or less; Mn: 1.0 to 2.5%; P: more than 0.030 to 0.048%; S: 0.025% or less; Al: 0.005 to 0.20%; N: 0.010% or less; Ti: 0.005 to 0.040%; Nb: 0.005 to 0.060%; and B: 0.0005 to 0.0030%, with the balance being Fe and impurities, satisfying Formula (1) to (4). A galvannealed layer contains 7 to 15 mass % of Fe. 25×P+4×Si≤3.6 (1)B−X1≥0.0005 (2)C−(12/93)×Nb−X2≥−0.0035 (3)110×Si+48×Mn+550×P≥120 (4)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.