মেটালার্জি MCQ
21. Pick up the wrong statement –
aluminium in steel results in excessive grain growth
manganese in steel induces hardness
nickel and chromiam in steel help in raising the elastic limit and improve the resilience and ductility
tungsten in steels improves magnetic properties and hardenability
22. Lead is poured into the joint between two pipes. These pipes may be made of--
cast iron
asbestos cement
vitrified clay
concrete
23. Which of the following material has maximum ductility?
Mild steel
Nickel
Copper
Aluminum
24. The percentage of carbon in grey iron castings usually varies between-
0.5 to 1%
2.5 to 4.5%
1 to 2%
5 to 7%
25. Copper when alloyed with zinc is known as--
Brass
Babbits
Bronze
All of the above
26. Recrystallisation temperature can belowered by--
purification of metal
grain refinement
working at lower temperature
all of the above
27. The percentage of carbon in pig iron varies from--
0.1 to 12%
2.5 to 4.5%
1.5 to 2.5%
4 to 4.5%
28. The following types of materials are usually the most ductile--
face-centred cubic lattice
body-centred cubic lattice
hexagonal close-packed lattice
all of the above
29. Amorphous material is one--
in which atoms align themselves in a geometric pattern upon solidification
in which there is no definite atomic structure and atoms exist in a random pattern just as in a liquid
which is not attacked by phosphorous
which is not attacked by phosphorous
30. The machinability of steel is increased by--
silicon and sulphur
phosphorous, lead and sulphur
sulphur, graphite and aluminium
phosphorous and aluminium
31. Vanadium in high speed steels--
promotes decarburisation
provides high hot hardness
forms very hard carbides and thus increases wear resistance
promotes retention of austenite
32. Pearlite is a combination of--
ferrite and cementite
cementite and gamma iron
ferrite and austenite
ferrite and iron graphite
33. Discontinous chips are formed during machining of--
brittle metal
hard metal
ductile metal
soft metal
34. Which of the following element results in presence of free graphite in CI--
carbon
silicon
sulphur
manganese
35. Which of the following iron exists 910°C?
∝-iron
δ -iron
β-iron
γ-iron
36. Iron-carbon alloys containing carbon........... 4.3% are known as hyper eutectic cast irons--
equal to
leas than
more than
none
37. The toughness of a material --when it is heated.
increases
remain same
decrease
none
38. Railway rails are normally made of –
mild steel
alloy steel
high carbon
tungsten steel
39. In which forging is possible without any problem?
alloy steel
low carbon
high carbon
cast
40. The lower critical point for all steels is—
600°C
700°C
723°C
913°C