METHOD FOR RECONSTRUCTING OUTSIDE AND INNER SURFACES OF STEEL PIPES WITHOUT INSIDE INSULATION Russian patent published in 2018 - IPC B08B9/00 B21D3/00 

FIELD: technological processes.

SUBSTANCE: invention concerns the restoration of outer and inner surfaces of steel pipes that do not have internal insulation and are dismantled from main pipelines (steam, gas, oil, water). Method includes cleaning both surfaces of pipes using gas-air flow heating and mechanical cleaning, restoration of the geometry of pipes, as well as mechanical preparation of the edges of pipes for welding. Gas-air flow with a temperature of 150–600 °C is fed into the pipes for simultaneous heating of the inner and outer surfaces of the pipe. Then, the coating residues from the outer surface of the pipe are removed using a mechanical tool. Outer and inner surfaces of the pipe are treated by feeding a gas-air flow saturated with dry sand. Then mechanically restore the geometry of the pipes and prepare the edges of the pipes for welding with the formation of chamfers from the outside of the edge at an angle of 30–40° and the inner chamfer at an angle of 5–20° with respect to the vertical axis of the pipe.

EFFECT: higher quality of reclaimed pipes.

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