METHOD FOR MAKING ANNULAR FORGINGS WITHOUT SLOPES Russian patent published in 2000 - IPC

FIELD: plastic metal working, namely manufacture of annular forgings without slopes by die forging in universal forming equipment. SUBSTANCE: method comprises steps of forming in forging die set annular blank with inclined walls, with bridge for piercing opening in the form of truncated dome arranged on end of small base of forging. Formed blank is placed onto piercing die in such a way that its bridge is turned upwards. At acting upon outer end of dome-like bridge by means of piercing punch, bridge is straightened. Radial displacement of bridge metal provides expansion of upper end of annular blank. At further motion of punch opening is pierced. Then blank is rotated by 180 deg. and it is placed into trimming die. Trimming punch has calibrating protrusion. When trimming punch is descended blank is calibrated along inner diameter and then burr is trimmed. At reverse stroke of press slide blank is stripped from calibrating protrusion by back side of trimming die. EFFECT: enhanced quality of forgings, reduced metal consumption. 2 dwg, 1 ex