| 摘要 |
PROBLEM TO BE SOLVED: To provide a joint for an oil well steel pipe having excellent sealability even under a severer working environment at low manufacturing cost only by performing a simple devise to a known joint. SOLUTION: Sealability of the joint for the oil well steel pipe is improved, which comprises a male member (a pin) having an annular outer circumferential surface and a male screw on a tip side of the steel pipe and a female member (a box) having a cavity to store the male member inside thereof, and has a female screw to be screwed in the male screw and an annular inner circumferential surface to be brought into contact with and butted to the annular outer circumferential surface of the male member in the cavity. More specifically, when the male member is connected to the female member, the annular outer circumferential surface of the male member and the annular inner circumferential surface of the female member are brought into contact with each other in an elastically deformable range to form a seal surface. COPYRIGHT: (C)2006,JPO&NCIPI
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