Drill pipe with upset ends having constant wall thickness and method for making same
US6808210B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1997 |
| Grant date | Oct 26, 2004 |
| Priority date | — |
| Expiry date | Oct 26, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/00
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drill pipe with cold upset ends. The drill pipe includes an elongate tubular portion with a pin joint on one end and a box joint on the other end. Each of the ends of the tubular portion is expanded using a cold upsetting process to provide a transitional portion and a joint receiving portion. The ends of the tubular portion have an inner and outer diameter which is greater than the inner and outer diameter of the tubular portion. The wall thickness of the tubular portion is substantially the same throughout its entire length, including the transitional portions and the joint receiving portions. A drill pipe made in accordance with this invention is durable and less costly to manufacture.A cold upsetting method by which the drill pipe is made utilizes no external heat. An internal mandrel is first inserted hydraulically into the ends of a tubular steel shaft to enlarge the ends. Then, an external “wipe over” die is applied to conform the wall of the ends being expanded to the shape of the internal mandrel. The pipe thus produced has a substantially uniform wall thickness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.