Electric resistance welded steel pipe having identifiable seam portion and method for manufacturing the same
US11045896B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 2019 |
| Grant date | Jun 29, 2021 |
| Priority date | — |
| Expiry date | Sep 25, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C22/12
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method for manufacturing an electric resistance welded steel pipe having an identifiable seam portion. The method includes electric resistance welding a steel pipe, cutting an inner surface bead and an outer surface bead of the steel pipe in such a manner so as to cut: (i) a whole the outer surface bead and a part of the inner surface bead to leave an uncut portion in the inner surface bead, or (ii) a whole of the inner surface bead and a part of the outer surface bead to leave an uncut portion in the outer surface bead, coating the steel pipe with zinc phosphate, and cold drawing the steel pipe using a plug and a die to make the seam portion of the steel pipe identifiable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.