Threaded joint for oil well pipes

摘要

A threaded joint for an oil well pipe having (1) a tapered threaded having roughly the shape of a buttress thread, (2) a pin having a male thread and a box having a female thread, (3) a seal and a torque shoulder, characterized in that (i) the load flank angle of the threads is -20 DEG or greater and less than 0 DEG , the stab flank angle is greater than 30 DEG and at most 60 DEG (ii) there is a positive amount of interference between the male threads and the female threads, and (iii) during and at the completion of make-up, the load flanks and the stab flanks are contacting each other, and there is a gap between the crests and the roots.