STEEL PIPE THREADED JOINT Russian patent published in 2015 - IPC F16L15/04 

FIELD: machine building.

SUBSTANCE: in a threaded joint when a pin and a box are coupled to each other by a threaded joint, the outer periphery surface of the front pin part and the inner periphery surface of the front box part contact each other metal-to-metal on the contact area, and the said contact area serves as a sealing area. The threaded area (where the area with external thread and the area with internal thread are connected by the threaded joint) has the negative angle α of the bearing surface, the thrust areas have the negative angle β for the application of torque, and the relation L/d0 of the front part length L and the outer pipe diameter d0 amounts to 0.08 or exceeds the said value.

EFFECT: threaded joint for steel pipes has high sealability even under bending load.

3 cl, 11 dwg