| US 7,494,159 B2 | ||
| Threaded joint for steel pipes | ||
| Masaaki Sugino, Nishinomiya (Japan); Miyuki Yamamoto, Otsu (Japan); Michihiko Iwamoto, Wakayama (Japan); and Shigeo Nagasaku, Nishihomiya (Japan) | ||
| Assigned to Sumitomo Metal Industries, Ltd., Osaka (Japan); and Vallourec Mannesmann Oil & Gas France, Aulnoye-Aymeries (France) | ||
| Filed on Feb. 23, 2007, as Appl. No. 11/710,060. | ||
| Application 11/710060 is a continuation of application No. PCT/JP2005/015828, filed on Aug. 24, 2005. | ||
| Claims priority of application No. 2004-248359 (JP), filed on Aug. 27, 2004. | ||
| Prior Publication US 2007/0236015 A1, Oct. 11, 2007 | ||
| Int. Cl. F16L 25/00 (2006.01) | ||
| U.S. Cl. 285—334 [285/333] | 14 Claims |
| 1. A threaded joint for a steel pipe having
a pin member having a tapered male thread, a metal seal-forming portion, and a torque shoulder-forming portion, and
a box member having a tapered female thread, a metal seal-forming portion, and a torque shoulder-forming portion corresponding
to those of the pin portion,
characterized in that the threads which constitute the tapered male thread and the tapered female thread have a first trapezoidal
thread portion which does not have simultaneous contact at the load flanks and the stabbing flanks, and a second trapezoidal
thread portion which has contact at the load flanks and stabbing flanks and which has gaps at the thread root surfaces and
the thread crest surfaces,
wherein the first trapezoidal thread portion has contact at the load flanks and the thread root surface, and gaps at the thread
crest surface and the stabbing flanks.
|