Seal 1 shows an axial half cross section for steel tube comprising a device for a section at the level of the threads

摘要

The invention concerns a steel tube threaded joint particularly useful in the petroleum industry of the type in which the male element (3) and female element (1) are combined by threading (2, 4) wherein a portion of the surface of each thread is forcefully applied to the status of screwing to the thread of the outer element. A first element (1) of the joint has a composite structure and has on at least a certain length of its thread a lining of synthetic material whose volume and shape correspond exactly to the volume and shape of the existing clearance of the screwing status between the metal part and composite element (1) and the second element (3) having dimensions at the limit of the machining tolerances which allow the greatest possible clearance in the assembled state of the joint.