Direction: In a multi-pass operation, a round bar of 10 mm diameter and 100 mm length is reduced in crosssection by drawing it successively through a series of seven dies of decreasing exit diameter. During each of these drawing operations, the reduction in crosssection area is 35%. The yield strength of the material is 200 MPa. Ignore strain hardening.
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Neglecting friction and redundant work, the force (in KN) required for drawing the bar though the first die, is
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- 15.71
- 10.21
- 6.77
- 4.39
Correct Option: D
Fd = K ln (R) σ Af
| × d²f1 = 0.65 | ×(10)² | 4 | 4 |
Fd = 4.39 KN
