Fatigue resistant drill pipe
US5853199A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 18, 1995 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Sep 18, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D1/18
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A tubular drill pipe section to be used in a well bore is disclosed. The drill pipe section includes upper and lower tool joints, a main steel tubular portion extending upwardly from the lower joint and terminating near the upper tool joint, and an elongated steel protector tube extending downwardly from the upper tool joint and secured to the upper end of the main portion. The main portion has a much lesser wall thickness throughout substantially its entire length than the protector tube. The protector tube is made of AISI 4100 series chrome-molly steel that is quenched and tempered to give it high strength and high hardness (30-38 HR.sub.c) with a Martensite small, close knit, grain size. This hard material reduces the penetration of the slip teeth into the wall of the pipe section and increases the fatigue life of the protector to beyond that of the main steel tubular portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.