11. | Machinability of hard alloys and tool steels is improved by |
a. | spherodising |
b. | annealing |
c. | tempering |
d. | normalising |
View Answer Report Discuss 50-50! |
Answer: (b).annealing
|
12. | Transformation range for ferrous material is the temperature interval during which __________ is formed during its heating. |
a. | cementite |
b. | austenite |
c. | martensite |
d. | pearlite |
View Answer Report Discuss 50-50! |
Answer: (b).austenite
|
13. | Powder metallurgy process does not make metal powder by |
a. | atomisation |
b. | grinding/milling |
c. | hammering |
d. | electrolytic deposition |
View Answer Report Discuss 50-50! |
Answer: (c).hammering
|
14. | In the blast furnace, incorporation of water vapour in the blast gives the following effect. |
a. | Increases the reducing potential of the gas. |
b. | Increases the flame temperature. |
c. | No significant change occurs. |
d. | Increases the hydrogen content in the metal. |
View Answer Report Discuss 50-50! |
Answer: (a).Increases the reducing potential of the gas.
|
15. | Pick out the wrong statement. |
a. | A ferromagnetic material becomes paramagnetic above the 'Curie temperature'. |
b. | Permanent magnets are made of hard materials, whereas electromagnets require soft magnetic materials. |
c. | Soft magnetic materials (e.g., pure iron) have higher permeability and low hysterisis loss and coercive forces. |
d. | Tungsten steel and alnico are not hard magnetic materials. |
View Answer Report Discuss 50-50! |
Answer: (d).Tungsten steel and alnico are not hard magnetic materials.
|