METHOD OF CORROSION PROTECTION OF INTERNAL ZONE OF WELDED JOINTS WITH INTERNAL COATING Russian patent published in 2015 - IPC F16L58/08 F16L58/18 

FIELD: metallurgy.

SUBSTANCE: under the method in the end of the connected pipes an assembled bushing is installed, it comprises telescopic external nozzles and internal corrosion-resistant nozzles. The internal nozzles are made with ring collar at the end, and are equipped at the external surface with the sealing rings. Prior to assemblage the internal nozzles are rigidly and coaxially connected by ends, reverse ends with ring collars. The internal surface of pipes and external surface of the internal nozzle under the sealing rings are treated by the antifriction substances. The assembled bushing with ends having ring collars and sealing rings is partially inserted in the ends of the connected pipes. The sealing rings are pressed by force movement of the external nozzles to the appropriate ring collars with securing relatively to the internal nozzle and with space sealing between the appropriate pipe and internal nozzle. Then by force axial shear the end faces of pipes are connected, and welding is performed.

EFFECT: method reduces expenses for anti-corrosion protection and increases its reliability.

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