| 摘要 |
This threaded fitting has, on the surface of a male thread (11), a solid coating (30) that exhibits fluidity when applied and is subjected to a hardening treatment after application. When fastening is complete, the crests (12) of the male thread (11) and the roots of a female thread, which face each other, are flat, and gaps are formed between those flat surfaces. A helical groove (40) that coincides with the helix angle of the threads is provided in advance in the crests (12) of the male thread (11). The maximum depth of said groove (40) is between 30 µm and 1/5th of the thread depth, inclusive. This threaded fitting prevents abnormal fastening torque and seizure during fastening without compromising strength performance. |
