Title:
PIPE THREAD JOINT
Document Type and Number:
WIPO Patent Application WO/2003/006867
Kind Code:
A1
Abstract:
A thread joint capable of economically imparting effective sealability to a metal surface contact seal section and preventing seizure during fastening is composed by fastening a steel pipe (1) having a male thread (1b) at an end and a non−threaded seal surface (1a) to a coupling (2) having a female thread (2b) in the inner peripheral surface and a non−threaded seal surface (2a). In this thread joint, letting Py be the inner surface yield pressure of the pipe, either (1) the mean surface pressure Pm of the annular contact portion satisfies Pm&sol Py ≥ 3, the axial width of the portion receiving the surface pressure Ps that satisfies Ps&sol Py ≥ 1 in the annular contact portion is not less than 1 mm (or not less than 2 mm), and the surface roughness (Ry) of the non−threaded seal surface is not more than 25 μm (or not more than 30 μm) or (2) the relationship between the mean surface pressure Pm of the annular contact portion and the surface roughness (Ry) (μm) of the non−threaded seal surface satisfies Pm&sol Py ≥ 0.0032 × Ry2 &plus 1.0, and in the annular contact portion, the axial width of the portion receiving the surface pressure Ps that satisfies Ps&sol Py ≥ 1 is not less than 1 mm.
Inventors:
MAEDA JUN (JP)
Application Number:
PCT/JP2002/007053
Publication Date:
January 23, 2003
Filing Date:
July 11, 2002
Export Citation:
Assignee:
SUMITOMO METAL IND (JP)
MAEDA JUN (JP)
MAEDA JUN (JP)
International Classes:
F16L15/04; F16L15/00; (IPC1-7): F16L15/00
Domestic Patent References:
| WO2001048411A1 | 2001-07-05 |
Foreign References:
| JPS639794A | 1988-01-16 | |||
| US4623173A | 1986-11-18 | |||
| US4692988A | 1987-09-15 | |||
| JPS61124792A | 1986-06-12 | |||
| JPH0610154A | 1994-01-18 | |||
| JPH0972467A | 1997-03-18 | |||
| JP2001065752A | 2001-03-16 | |||
| US4732416A | 1988-03-22 | |||
| US4623173A | 1986-11-18 | |||
| US5137310A | 1992-08-11 | |||
| US5423579A | 1995-06-13 | |||
| JPS61124792A | 1986-06-12 | |||
| JPH0610154A | 1994-01-18 | |||
| JPH07217777A | 1995-08-15 | |||
| JPH08145248A | 1996-06-07 |
Other References:
See also references of EP 1408269A4
Attorney, Agent or Firm:
Hirose, Shoichi (4-2 Nihonbashi Honcho 4-chom, Chuo-ku Tokyo, JP)
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