METHOD TO PRODUCE HEAT EXCHANGE TUBES WITH SHAPED TIPS Russian patent published in 2010 - IPC B21D53/08 B21D41/00 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and can be used in producing heat exchange tubes exploiting, to this end, the effect of localized directed plastic deformation of tube material. Tube processed, that is, straightened, cut to required extent and its outer surface ground, its end is sized by rigid die. Sized section is subjected to stepwise radial reduction by segments of composite die. Said die has finishing and preliminary engravings and radial work belt arranged there between. Radial squeeze is performed with tube edge thrusting against die tip fitted in the die finishing plate. Note here that sized tube end is subjected to re-sizing to maximum and minimum reduction sections with a taper transition there between. Tube inner space of subjected to mandrelling on maximum reduction section on tube end. This forces tube material out from work belt of the composite die in axial direction to partially fill the composite die plate and form compensation element in the form of a bulge on the tube maximum reduction end section.

EFFECT: expanded processing performances.

6 dwg