METHOD FOR MAKING SEMIHOLLOW ROD TYPE STEPPED PARTS Russian patent published in 2004 - IPC

FIELD: plastic metal working, possibly manufacture of parts such as rivets, bodies of tenons, shafts, axles and pins in cold upsetting automatic machines. SUBSTANCE: method comprises steps of cutting off measured-length blank; successively calibrating it and stamping on it outline; performing forward extrusion for forming dead cavity in one end of rod type blank; making stepped semifinished product by reducing blank in die and squeezing wall of dead cavity; calibrating dead cavity onto calibration mandrel; finally shaping head on other end of rod; realizing reduction of wall of dead cavity onto calibration mandrel arranged in such a way that it floats in zone of reduction deformation according to condition providing (at next calibration stage) friction forces acting between mandrel and wall of dead cavity in order to hold mandrel entrapped by blank while not preventing axial yield of metal of wall of dead cavity. EFFECT: enhanced strength of tool, improved quality of parts. 2 dwg