Steel tube alloy
US5226978A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1991 |
| Grant date | Jul 13, 1993 |
| Priority date | — |
| Expiry date | Aug 28, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/909
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Seamless steel tubes suitable for use as grades of casing and line pipe having yield strengths in excess of 70,000 psi, without being heat treated, are made of an alloy comprising, by weight, about 0.10% to 0.18% carbon, about 1.0% to 2.0% manganese, about 0.10% to 0.16% vanadium, about 0.008% to 0.012% titanium and about 150 parts per million to 220 parts per million nitrogen, the balance comprising iron and incidental impurities. Strains are applied to the shell in a stretch reducing mill below the T.sub.nr of the steel and above the A.sub.r3 to provoke dynamic recrystallization. The nitrogen and vanadium are preferably introduced to the steel during alloying in the form of a VN alloying agent. The vanadium, titanium and nitrogen are predominantly present as vanadium nitride and titanium nitride. The steel may also comprise 0.03% to 0.05% aluminum by weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.