Patent ID: 8038179
Filing Date: 2011-10-18
Classification: E21B,F16L

Abstract:
1. A threaded joint for steel pipes comprising a pin having a male thread, a sealing surface, and an end shoulder surface sequentially arranged from the rear towards the end of the pin, and a box having a female thread, a sealing surface, and a shoulder surface corresponding to the male thread, the sealing surface, and the shoulder surface of the pin, respectively, wherein the threads are tapered threads and the sealing surfaces are tapered surfaces, characterized in that the pin and the box each have a noncontacting region between the sealing surface and the shoulder surface where the peripheral surfaces of the pin and the box do not contact each other, and at least a portion of the noncontacting region of the pin adjoining the end of the pin is a tapered surface portion having substantially the same angle of slope as the sealing surface.