DRILL PIPE WITH DOUBLE SHOULDER TOOL JOINTS

摘要

A drill pipe with double shoulder tool joints by which a stress concentration can be relaxed and provided with an excellent fatigue characteristic without largely changing a predetermined threaded portion shape is provided. A drill pipe (1) with a double shoulder tool joint includes a pin (3) including a male threaded portion (30) having a predetermined shape, and a box (2) including a female threaded portion (20) to be screwed with the male threaded portion (30), and a stabbing flank (41) of each of three or less consecutive proximal thread ridges on a larger-diameter side of the male threaded portion (30) and/or three or less consecutive proximal thread ridges on a smaller-diameter side of the female threaded portion (20) includes a round processed portion.