| 摘要 |
As a result of a case in which contact occurs at a stabbing flank surface (31B) being assumed in the prior art, it is not possible to reduce the action of a high concentrated load when the high concentrated load acts on a load flank surface (30P) of a threaded section on a pin pipe end side. Provided is a thread joint for an oil well pipe comprising a premium joint wherein a female thread pitch (20B) has the same value as a male thread pitch (20P) from a thread end section of the end side of a box (1) to a pitch change position (PCP) that is more to the central side of the box than a position that is one half the total length of the threaded section. The pitch changes at the pitch change position (PCP) to a value that is less than the male thread pitch so that a thread gap (10) gradually decreases from the pitch change position (PCP) to the thread end section of the central side of the box. As a result of the pitch change, the thread gap (10) reaches a final value of 0.2-0.8 times the value thereof prior to said pitch change. |
