Apparatus for producing a bulge in thin metal material

摘要: A tube bulger for producing an enlarged ring-like bulge in the material around end portion of a metal includes upper and lower die sections. When sections are mated together, cylindrical hole is formed. The to be bulged extends into hole. ring-like, outwardly oriented enlargement forms cavity which moves as it being An elongated mandrel through opposite open tube. First second sealing rings disposed about on sides prevent leakage pressurized oil between mandrel. conducting channel has opening rings. high pressure source forces channel, out opening, thereby applying inner wall first rings, causing initial outward bulging cavity. shoulder abuts tube, moved inward toward recess, sliding extreme partially formed engages cavity, preventing side Additional then while continues applied. occurs, until fills up without excessive thinning materials bulge.