| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem that there is a room for improving rigidity of a pin nose to secure sealing properties, in a steel pipe screw joint of a radial seal type. <P>SOLUTION: A nose part outer circumferential surface at a pin 3 side has a taper shape. A seal surface at a box 1 side has an outwardly convex curved surface shape. A sectional area of the pin in a seal point sp being a region on the nose part outer circumferential surface at the pin side that is first in contact with a box side seal surface during screw connection is 35% or more of the sectional area of an element pipe being a pin non-worked part. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
