| 摘要 |
An oil well tubing joint coated with a carbide blast coating provides an elongated, hollow tubing section having an open ended continuous cylindrical internal bore and a continuous carbide coating over substantially all of the tubing section outer surface. An internally threaded connection portion of the bore at a first end of the tubing section is provided with an externally threaded connection member being positioned at the second end of the tool bore. The tubing section has a larger constant external diameter that extends over a majority of its length and three reduced external diameter portions that extend a distance from each end of the tubing, including one reduced diameter portion adjacent one end of the tubing joint and two of the reduced diameter portions being adjacent the second end of the tubing joint. The reduced diameter portions include preferably two portions having "flats" for providing power tightening surfaces that allow wrenches to grip and bite the tool body notwithstanding the carbide coating, and a third reduced external diameter section for slip relief.
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