Steel material for highly deformable line pipes having superior strain aging resistance and superior HIC resistance, method for manufacturing same, and welded steel pipe
US10465261B2 · kind B2 · utility
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Key dates
| Filing date | Mar 26, 2015 |
| Grant date | Nov 5, 2019 |
| Priority date | — |
| Expiry date | Dec 25, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel material for highly deformable line pipes that has superior strain aging resistance, superior HIC resistance, and a metallographic structure including ferrite, bainite, and martensite-austenite constituent. The area fraction of the martensite-austenite constituent is 0.5 to 5.0%, and the difference in hardness between the ferrite and the bainite is 60 or more in terms of Vickers hardness. Additionally, the steel material has a uniform elongation of 9% or more and a yield ratio of 90% or less both before a strain aging treatment at a temperature of 300° C. or lower and after the strain aging treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.