Threaded joint for pipes
US6957834B2 · kind B2 · utility
Assignees
Inventor
Key dates
| Filing date | Jul 25, 2003 |
| Grant date | Oct 25, 2005 |
| Priority date | — |
| Expiry date | Mar 9, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S285/917
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A threaded joint which economically imparts effective sealing properties to a metal-to-metal seal portion and which can prevent seizing at the time of make-up comprises a steel pipe 1 having at its tip a male thread 1b and an unthreaded sealing surface 1a, and a coupling 2 having on its inner surface a female thread 2b and an unthreaded sealing surface 2a. With the yield pressure of the inner surface of the pipe being Py, (1) the average pressure Pm of the annular contact portion satisfies Pm/Py≧3, and the width in the axial direction of the portion which receives a pressure Ps which satisfies Ps/Py≧1 in the annular contact portion is at least 1 mm (or at least 2 mm), and the surface roughness Ry of both unthreaded sealing surfaces is at most 25 μm (or at most 30 μm), or (2) the relationship between the average pressure Pm of the annular contact portion and the surface roughness Ry (μm) of the unthreaded sealing surface satisfies Pm/Py≧0.0032×Ry2+1.0, and the width in the axial direction of the portion which receives a pressure Ps which satisfies Ps/Py≧1 in the annular contact portion is at least 1 mm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.