Consider the following in case of high energy forming processes:
1. The evacuation between die and blank in explosive forming is done by a vacuum jump
2. The pressure waves produced in water in explosive forming deform the blank to the die shape
3. The electrohydraulic forming makes use of discharge of large amount of electrical energy used in a capacitor bank
4. In petrogorge, the piston is moved by combustion of fuel moving at the rate of 150-200 m/s.
Which of the above are correct?
(a) 1,2,3 and 4 (b) 1,2 and 3 only
(c) 3 and 4 only (d) 1,2 and 4 only