METHOD FOR MAKING SEMIHOLLOW ROD-SHAPED STEPPED PARTS Russian patent published in 2001 - IPC

FIELD: plastic metal working, possibly manufacture of semihollow rod-shaped stepped parts such as rivets, bodies of tenon, shafts, axles and pins in cold upsetting automatic machines. SUBSTANCE: method comprises steps of cutting measured-length blank; successively sizing it at pressing out marking; performing forward extrusion for making dead cavity in one end of rod; reducing it in lower die with cone deforming portion and outlet sizing portion for making stepped semifinished product having dead cavity on end of less step and finally forming head in other end; combining reducing in lower die with swaging of wall of dead cavity on sizing mandrel arranged at side of end of less step outside of cone deforming portion of lower die. Axial yielding of metal of wall of dead cavity and its shape are set due to contact friction or due to configuration of outlet sizing portion of lower die at next relation of sizes of dead cavity: S/Dp is less than 0.2, where S is thickness of wall of dead cavity of part; Dp is outer diameter of wall of dead cavity of part. EFFECT: enhanced quality of parts, improved strength of tools. 1 dwg, 1 ex