Thick-walled high-strength hot rolled steel sheet having excellent hydrogen induced cracking resistance and manufacturing method thereof
US9809869B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 2016 |
| Grant date | Nov 7, 2017 |
| Priority date | — |
| Expiry date | Dec 12, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/002
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A thick-walled high-strength hot rolled steel sheet having excellent hydrogen induced cracking resistance which is preferably used as a raw material for a high-strength welded steel pipe of X65 grade or more and a method of manufacturing the thick-walled high-strength hot rolled steel sheet are provided. The composition of the thick-walled high-strength hot rolled steel sheet contains by mass % 0.02 to 0.08% C, 0.50 to 1.85% Mn, 0.02 to 0.10% Nb, 0.001 to 0.05% Ti, 0.0005% or less B in such a manner that (Ti+Nb/2)/C<4 is satisfied or also contains one or two kinds or more of 0.010% or less Ca, 0.02% or less REM, and Fe and unavoidable impurities as a balance. The steel sheet has the structure formed of a bainitic ferrite phase or a bainite phase. Surface layer hardness is 230HV or less in terms of Vickers hardness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.