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

FIELD: plastic metal working, namely processes for making heat exchange tubes with profiled outer end portions. SUBSTANCE: method comprises steps of expanding end of tube; forming calibrated portion and reducing it along length less than initial one in order to make transition cone portion; placing end portion of tube into detachable die in such a way that cone transition portion is arranged in front of annular recess of die; fixing tube against its possible motion by bending calibrated portion of tube in radial direction by means of die protrusion at introducing material of transition cone portion in annular recess of die; then forming annular outer protrusion on tube by applying to its end axial compression effort for providing plastic yielding of tube material to annular recess of die. EFFECT: lowered tube deforming efforts. 5 dwg