The pressure required to maintain flow during indirect extrusion
P. decreases with decreasing rate of the billet
Q. Increases with increasing extrusion ratio
R. is independent of the length of the billet
S. is independent of the extrusion ratio

In a tensile test of ductile material, necking starts at

A. lower yield stress

B. upper yield stress

C. ultimate tensile strength

D. just before fracture

A metallic sheet 1 m wide and 10 mm thick is to be rolled under a front tension force of 100 KN. A specimen from the sheet, tested under tension, shows a yield stress of 100 MPa. Assume plain strain condition during rolling and ignore the friction. If yielding is assumed to start at a roll pressure of σ3 MPa, then the stress in the width direction (where strain is zero) is

A. $$2 + \frac{{\sigma 3}}{2}$$

B. $$4 + \frac{{\sigma 3}}{5}$$

C. $$5 + \frac{{\sigma 3}}{2}$$

D. $$5 + \frac{{\sigma 3}}{3}$$

Match the forming methods in Group 1 with the defects in Group 2.

A. P-1, Q-2, R-3

B. P-4, Q-3, R-1

C. P-3, Q-1, R-4

D. P-2, Q-1, R-3

The maximum axial compression stress during cold upsetting of a cylindrical rod of radius, 'r', occurs at

A. the outer edges of the rod

B. $$\frac{r}{3}$$ from the centre

C. $$\frac{r}{2}$$ from the centre

D. the centre