To provide a hydraulic forming method and a hydraulic forming apparatus by which residual gas is surely discharged from the inside of a base stock even when the shape of a recessed part for forming is a shape which is liable to leave the gas and good hydraulic forming is performed.
This method is a hydraulic forming method by which a formed article matched to the shape of the forming recessed part is formed by charging the base stock 10 in a forming die 30 provided with forming recessed parts 33, 34 on which projecting parts 33a, 34a which are upward projected, clamping and applying liquid pressure in the base stock. Then, the gas 15 which is left in the projecting part 13 on the base-stock side which is formed on the base stock and projected upward is discharged by pulsating a liquid medium 21 for imparting the liquid pressure and, after that, the hydraulic forming is performed.
SAKURAI HIROSHI
Yasuo Nara
Etsuko Saito
Katsuyuki Utani
Toshifumi Fujii