Low yield ratio, high strength and high toughness steel plate and method for manufacturing the same
US8778096B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 2010 |
| Grant date | Jul 15, 2014 |
| Priority date | — |
| Expiry date | Sep 28, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided is a low yield ratio, high strength and high toughness steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. The steel plate has a metallographic microstructure that is a three-phase microstructure including bainite, M-A constituent, and quasi-polygonal ferrite, the area fraction of the bainite being 5% to 70%, the area fraction of the M-A constituent being 3% to 20%, the remainder being the quasi-polygonal ferrite, the equivalent circle diameter of the M-A constituent being 3.0 μm or less. The steel plate has a yield ratio of 85% or less and a Charpy impact test absorbed energy of 200 J or more at −30° C. before or after being subjected to strain ageing treatment at a temperature of 250° C. or lower for 30 minutes or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.