61. The flow stress (σ) of an alloy varies with strain rate $$\left( \in \right)$$ as σ = 100 $${\left( \in \right)^{0.1}}$$ MPa. When the alloy is hot extruded from 10cm diameter to 5 cm diameter at a speed of 2 cm/s, the flow stress is
62. For successful rolling, the condition required is
63. A metal powder with an apparent density of 2.5 g/cm3 was compacted in a cylindrical die to a green density of 5.5 g/cm3, If the height of the green sample was 12 mm, then the fill height of powder (in mm) would have been
64. Tungsten filament wire for lamp industry is commonly produced by
65. Match the following:
Group 1
Group 2
P. Direct extrusion
1. Motion of ram and work piece in the same direction
Q. Impact extrusion
2. Motion of ram and work pieces in the opposite direction
R. Tube drawing
3. No containerwall friction
S. Hydrostatic extrusion
4. Use of mandrel
| Group 1 | Group 2 |
| P. Direct extrusion | 1. Motion of ram and work piece in the same direction |
| Q. Impact extrusion | 2. Motion of ram and work pieces in the opposite direction |
| R. Tube drawing | 3. No containerwall friction |
| S. Hydrostatic extrusion | 4. Use of mandrel |
66. A planetary mill is used for
67. An aluminium billet of 300 mm diameter is extruded with an extrusion ratio of 16. What is the diameter of the final product?
68. Match the process with the property required.
P. Cold rolling
1. Wettability
Q. Milling
2. Ductility
R. Brazing
3. Comparability
S. Powder metallurgy
4. Machinability
| P. Cold rolling | 1. Wettability |
| Q. Milling | 2. Ductility |
| R. Brazing | 3. Comparability |
| S. Powder metallurgy | 4. Machinability |
69. Match the phenomenon with typically observed features
P. Fatigue fracture
1. Earing
Q. Yield point phenomenon
2. Dimple structure
R. Ductile fracture
3. Beach marks
S. Deep drawing of a sheet
4. Luder's band
| P. Fatigue fracture | 1. Earing |
| Q. Yield point phenomenon | 2. Dimple structure |
| R. Ductile fracture | 3. Beach marks |
| S. Deep drawing of a sheet | 4. Luder's band |
70. The strain hardening behaviour of an annealed rod during cold rolling is given by σ = 700 $${\left( \in \right)^{0.2}}$$ MPa. where σ is the flow stress at strain $$ \in $$.
Flow stress after 50% reduction in area of the annealed rod on cold rolling is approximately
Flow stress after 50% reduction in area of the annealed rod on cold rolling is approximately