Method of forming seamed metal tube
US5915421A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1997 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Jul 10, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49986
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The method of forming a seamed metal tube having a metal coating of this invention includes applying a metal coating to the upper face of a metal strip prior to welding. The strip is then formed into an open seam tube and welded, preferably in a non-oxidizing atmosphere with the seam preferably located in the lower portion of the tube. Finally, at least a lower portion of said tube is reheated with the seam located in the lower portion of the tube, thereby causing the metal coating to flow downwardly over the seam, coating the seam. In one embodiment, the strip is preformed into an arcuate shape and coated, wherein the metal coating increases in thickness toward the lateral strip edges, such that the coating will flow over the seam following welding. The inside coated seamed tube may also be immersed in a galvanizing or metal coating bath to coat the outside of the tube. In a preferred embodiment, the inside and outside coatings comprise substantially the same metal and a single galvanizing bath apparatus is used to coat the inside and outside surfaces of the seamed tube. In another embodiment, the coating on the inner surface of the seamed tube has a melting temperature substantia…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.