Patent ID: 8052173

Claim:
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 ( 25 ) with friction properties lower than the friction properties of the non-metallic coating comprising the first layer is laid only on specific parts of the overall surface of the pin member or box member, 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.