THREADED CONNECTION FOR STEEL PIPE Russian patent published in 2019 - IPC F16L15/04 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to a threaded joint for a steel pipe. Nipple (10) includes, in the order from free end of nipple (10): shoulder surface (11), first sealing surface (12), first section (13) with external thread, second sealing surface (14) and second section (15) with external thread. Coupling (20) includes shoulder surface (21), first sealing surface (22), first section (23) with internal thread, second sealing surface (24) and second section (25) with internal thread. Angles of inclination of loaded sides (13d and 23d) of first section (13) with external thread and first section (23) with internal thread make less than 0°. First section (13) with external thread consists, in the order from the place near the second sealing surface (14), from: section (31b) of incomplete thread and section (31a) of full thread. Section (31b) of incomplete thread has length at least equal to triple value of its thread pitch, and has thread height smaller than thread height of section (31a) of full thread. Section (31b) of incomplete thread is provided with gaps between flanges (13a and 23a) and cavities (23b and 13b).

EFFECT: invention improves threaded connection reliability.

6 cl, 4 dwg, 1 tbl