THREADED JOINT FOR STEEL PIPES

摘要

A threaded joint is constructed of a pin and a box. The pin includes, in order from an end thereof, a shoulder surface, a nose portion, a first sealing surface, a first male threaded portion, an annular portion, a second sealing surface, and a second male threaded portion. The box includes a shoulder surface, a recessed portion, a first sealing surface, a first female threaded portion, an annular portion, a second sealing surface, and a second female threaded portion. In the threaded joint, in a fastened state, the shoulder surfaces are in contact with each other, the first sealing surfaces are in contact with each other, the second sealing surfaces are in contact with each other, a clearance is provided between the nose portion and the recessed portion, a clearance is provided between the annular portions.

主权项

1. A threaded joint for steel pipes, comprising: a tubular pin and a tubular box, the pin and the box being fastened by screwing the pin onto the box,
the pin comprising: in order from an end thereof, a shoulder surface; a first sealing surface; a tapered first male threaded portion; a second sealing surface; and a tapered second male threaded portion, the box comprising: a shoulder surface; a first sealing surface; a tapered first female threaded portion; a second sealing surface; and a tapered second female threaded portion, corresponding to the shoulder surface, the first sealing surface, the first male threaded portion, the second sealing surface, and the second male threaded portion, of the pin, respectively, wherein, the pin further includes: a nose portion disposed between the shoulder surface and the first sealing surface, the nose portion being continuous with the first sealing surface; and an annular portion disposed between the first male threaded portion and the second sealing surface, the annular portion being continuous with the second sealing surface, the box further includes: a recessed portion corresponding to the nose portion of the pin; and an annular portion corresponding to the annular portion of the pin, and in a fastened state: the shoulder surfaces are in contact with each other; the first sealing surfaces are in contact with each other; the second sealing surfaces are in contact with each other; a clearance is provided between the nose portion of the pin and the recessed portion of the box; a clearance is provided between the annular portion of the pin and the annular portion of the box; the first male threaded portion engages with the first female threaded portion; and the second male threaded portion engages with the second female threaded portion.