CLAMP METHOD OF DIE FOR SUPERPLASTICITY FORMING

PROBLEM TO BE SOLVED: To provide a technology to preferably clamp a die for superplasticity forming. SOLUTION: In figure (a), in die clamping, the A pressing faces 39... and the B pressing faces 39... shown in black colored are set to high clamp force, the C pressing faces 39... and the D pressing faces 39... shown in void are set to low clamp force. A figure (b) shows setting of a clamp means when heating is progressed somewhat, a high pressure gas is blown between upper/ lower dies 11, 13 for blow forming and a die inside pressure is increased somewhat, that is, the clamp force at the C pressing faces 39... and the D pressing faces 39... apart from the center are increased, the whole A-D pressing faces 39 are strongly pressed. Thus, both of the suppression of generation of thermal stress and the sufficient increase of die clamp force are satisfied.