METHOD OF PRODUCING HEAT EXCHANGE PIPES WITH PROFILED EDGES Russian patent published in 2010 - IPC B21D53/08 B21D41/00 F28F1/00 

FIELD: metallurgy.

SUBSTANCE: pipe prepared, its end is fitted in split die cavity. Die has finish and preliminary cavity surfaces, outer and inner cylindrical belts and end face collar. Pipe end is arranged in die cavity so that it gets in contact with end face collar. Pipe locked, mandrel with working and forming teeth is inserted into die cavity. Working tooth is arranged to stay in contact with pipe bore edge. Forming tooth outer edge is arranged opposite die cylindrical inner belt outer edge. Pipe end is radially squeezed by split die segments on mandrels. Squeezing force is produced on pipe section between working and forming teeth. Said force provides for preliminary filling die finish shape with pipe material. Then mandrelling of squeezed pipe section is performed. Note here that rest volume of die finish shape is filled with pipe material and this material is extruded into preliminary die shape to produce pipe end bulge.

EFFECT: higher quality.

4 dwg