Martensitic stainless steels for seamless steel pipe
US5939018A · kind A · utility
4Cited by
5References
4Claims
0Family size
Assignee
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Key dates
| Filing date | Nov 29, 1996 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Nov 29, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D8/105
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Martensitic stainless steels that enable the fabrication of high-strength seamless steel pipe suited for use in oil-well pipe and pipeline tubing by means of a Mannesmann plug mill or Mannesmann mandrel mill process, without the formation of defects during production. The heat workability of these steels, which contain no more than 0.30% by weight of carbon and from 11 to 14% by weight of chromium, and have a ferrite content of at least 40% at 1200.degree. C., has been vastly improved by holding the phosphorus and sulfur levels therein to no more than 0.020% and 0.003% by weight, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.