THREADED JOINT

WIPO Patent Application WO/2018/135536

A1

A threaded joint capable of ensuring a high level of sealing performance is provided. A threaded joint (10) is provided with a pin (1) and a box (2). An inner male threaded section (13) of the pin (1) includes a parallel section (131). The parallel section (131) is positioned at an end part of a pin inner seal surface (11) side of the inner male threaded section (13), and thread root surfaces are formed in parallel to a pipe axis. An inner female threaded section (23) of the box (2) includes a tapered section (231). The thread height of the tapered section (231) is taller than the thread height of the parallel section (131). In a vertical cross-section of the pin (1) and box (2) in a non-fastened state, Da