Assumptions adopted in the analysis of open die forging are
1. Forging of friction is constant between work piece and die
2. Coefficient of friction is constant between work piece and die
3. Stress in the vertical (Y–direction) is zero.
(a) 1 and 2 only (b) 1 and 3 only
(c) 2 and 3 only (d) 1, 2 and 3