METHOD OF TRIMMING LONG HEAT EXCHANGE TUBE ENDS Russian patent published in 2012 - IPC B21C37/30 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used for production of heat exchangers. Heat exchange tube is fitted in cavity of hydraulic press clamping mechanism so that its end extends beyond mechanism face surface. Tube is fixed to trim extending end inner and outer diametres, to form end bulge and to condition trimmed outer surface. For this, tube end is expanded to make outer diametre exceeding that of end bulge. Then, tube end is arranged in cavity of split female die with combined bed and gage. Said bed is located at the distance from gage equal to end bulge width. Tube end is radially reduced to diametre equal to end bulge outer diametre. Then, mandrel is fitted inside reduced tube end to shape it to required accuracy. Then, axial contraction force is applied to tube end by mandrel larger section to gage outer diametre. Surface layer excess is extruded into bed. At final stage of gaging, excess is removed from tube end.

EFFECT: higher quality of finished products.

6 dwg