Patent ID: 8052173
Filing Date: 2011-11-08
Classification: C10M,C10N,E21B,F16B,F16L

Abstract:
1. A dope-free threaded joint for pipes, the joint comprising a pin member ( 100 ) and a box member ( 200 ), the pin member having a thread adapted to match a thread of the box member, a thread form of each of the pin member and the box member being defined by a thread profile that lays on a cross-section containing a longitudinal axis (X) of the joint, wherein the surface of the pin member is provided with a non-metallic coating comprising a first layer ( 24 ) with high friction and anti-seize properties laid on the overall surface of the pin member ( 100 ), wherein a second layer ( wherein the specific parts are parts of the surface that produce reciprocal radial contact between the pin member and the box member during make-up until an abutment surface withstanding an axial contact pressure load abuts either one of the pin member or the box member, and wherein a friction coefficient between axial contact surfaces of the pin member and the box member is at least twice a friction coefficient between radial contact surfaces of the pin member and the box member.