Weathering steel
US10174398B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 2016 |
| Grant date | Jan 8, 2019 |
| Priority date | — |
| Expiry date | Dec 17, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/58
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of making weathering steel by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, <0.6% silicon, 0.2%-2.0% manganese, <0.03% phosphorus, <0.01% sulfur, <0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, <0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip ≤4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Ar3 to between 10% and 50% reduction, cooled at above 20° C./s and coiled below 700° C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.