METHOD OF PRESSURE-RAM-FORMING METAL CONTAINERS AND THE LIKE

摘要

A method of forming a bottle-shaped or other contoured metal container by subjecting a hollow metal preform having a closed end to internal fluid pressure to cause the preform to expand against the wall of a die cavity (10 ) defining the desired shape, and advancing a punch (12) into the die cavity (10) to displace and deform the closed end of the preform either before or after expansion begins but before it is complete. The pressure-subjecting st ep is performed by simultaneously subjecting the preform in the die cavity to independently controllable internal and external positive fluid pressures an d varying the difference between them to control strain rate.