Method for manufacturing joint of carbon steel pipes suitable for expansion and expanding method
US6378760B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2000 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Aug 22, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2101/06
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Carbon steel pipes are joined to each other in a non-oxidizing atmosphere by using an insert constituted by a Ni-base alloy or a Fe-base alloy having a melting point which is lower than 1200° C. and a thickness of 80 mm or smaller under conditions that the surface roughness Rmax of the joined surfaces of the carbon steel pipes is 20 &mgr;m or smaller, the joining temperature is not lower than 1250° C. nor higher than 1330° C., duration at the joining temperature is 30 seconds or longer and the pressure is not lower than 2 MPa nor higher than 4 MPa. The expanding operation is performed such that the maximum difference in level of the joined portion is not larger than 25% of the carbon steel pipe and the expansion ratio is 25% or lower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.