| 摘要 |
A tubular body made of a first metal and having a box end and a connection end, the box end having an internally threaded portion and an internal cylindrical thread-free portion axially outward of the threaded portion, the tool joint further including an anti-fretting section, preferably in the form of a sleeve of a second metal that is snugly received in a counterbore formed in the box end, the sleeve having an internal cylindrical surface having a diameter substantially the same as the internal diameter of the cylindrical thread-free portion of the box end, the second metal having a modulus of elasticity less than the modulus of elasticity of the first metal, the invention further including a drill pipe made by affixing first and second tool joints as described above to first and second opposed ends, respectively, of an elongate pipe body, the pipe body being affixed to the tool joints by a threaded shrink-grip connection, the first tool joint forming a box connection, the second tool joint forming a pin connection.
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