METHOD OF MAKING CURVED HOLLOW TUBE Russian patent published in 2016 - IPC B21D5/01 

FIELD: technological processes; metallurgy.

SUBSTANCE: invention relates to metal forming, particularly for making three-dimensionally bent pipe. At stage of rough forming in processed material formed extruded section and locking its cantilever sections. At stage of forming said two flanges bending curved section between propelling section and cantilever sections in opposite directions, preserving bent between cantilever sections and flanges. At stage of internal folding flanges are approach flanges to each other in section outside three-dimensionally curved section. At final stage performed connection flanges facing each other.

EFFECT: uniform thickness of the pipe.

4 cl, 30 dwg