Tubular threaded joint with trapezoid threads having convex bulged thread surface

摘要

A threaded tubular connection comprises two elements, male and female, made up one into the other to a given torque in which, prior to making up, at least one thread face under contact pressure (125) has a convexly rounded shape that is continuous over its width with a radius of curvature in the range 2 to 60 mm and is in point contact with the corresponding face (26) of the mating element. Such a threaded connection has an increased resistance to breakout or to overtorquing. In one embodiment, the convexly rounded face (125) is a male or female thread flank and one of the male or female threads comprises a groove (31) opening into the thread crest (29) to render flexible either the convexly rounded flank (125) or the corresponding flank. Such a geometry can accommodate variations in contact between the flanks.