METHOD FOR MAKING HEAT EXCHANGE TUBES WITH SHAPED ENDS Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely processes for making thick wall tubes with shaped ends. SUBSTANCE: method comprises steps of forming outer annular protrusion on end of tube by successively performing operations of tube end expansion and crimping; then placing tube end into opening of detachable lower die while arranging outer annular protrusion opposite relative to annular groove of lower die; fixing tube by means of lower die at applying compression effort to surface of outer annular protrusion of tube; then applying to tube end axial compression effort and providing plastic yielding of tube material into annular groove of lower die; at applying axial effort calibrating outer annular protrusion of tube. EFFECT: possibility for making shaped ends of thick-wall tubes at applying relatively small deforming efforts. 5 dwg