Importance

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Abstract

A joint of drill pipe is disclosed that has a tube section with upset ends to increase the wall thickness of the tube at its ends and tool joints connected to each end of the tube. Each tool joint has a cylindrical section connected to a weld neck of diameter by a tapered section. The connection between the tapered section and the weld neck has a radius of curvature and the weld neck has a wall thickness equal to that of the upset end of the tube that is welded to the weld neck. An external, stress relief groove is located in the weld neck to increase the fatigue life of the tube section of the drill pipe when the drill pipe is subjected to varying stresses produced by rotating the drill pipe while bent. One end of the relief groove is arcuate and is an extension of the radius of curvature between the tapered section and the weld neck. The groove may be arcuate in cross-section or it may have arcuate end sections with a cylindrical section between the end sections.

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First Claim