1. Thisset of MaterialsScience Multiple Choice Questions&Answers(MCQs) focuseson“CastIrons”.
1. Which of the followingcanbe carboncompositionof castiron?
a) 1%
b) 1.5%
c) 0.5%
d) 2.5%
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Answer:d
Explanation:The carboncomposition incastironismore than 2% and hence only2.5% can be
correct answeras all the answerlie outside the range.
2. Cast iron tendstobe brittle.
a) True
b) False
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Answer:a
Explanation:The above statementiscorrect.Castiron tendstobe brittle because of the presence of
a highamountof carbon init.
3. At what temperature doespure ironturnintoFCCstructure?
a) 800 °C
b) 900 °C
c) 910 °C
d) 810 °C
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Answer:c
Explanation:Pure ironturnsintoitsFCCstructure at a temperature of 910 °C. This structure iscalled
gamma ironor γ-iron.
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2. 4. Which of the followingalloyingelementforcesthe carbonoutof the solution?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Answer:a
Explanation:Siliconisusedin acast iron to bringoutthe carbonfrom the solution.If alarge amount
siliconisaddedgreycastiron isformed.
5. Which of the followingalloyingelementincrease hardness?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Answer:b
Explanation:The presence of sulfurincrease the hardnessof the alloybyreactingwithirontoform
ironsulphide.
6. Which of the followingalloyingelementrefinespearlitestructure?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Answer:c
Explanation:Nickel isthe mostcommonalloyingelementincastiron.It helpsinrefiningthe pearlite
and graphite structure.
7. Which of the followingalloyingelementisaddedasa degasser?
a) Silicon
3. b) Sulphur
c) Nickel
d) Titanium
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Answer:d
Explanation:Titaniumisaddedasadegasserandit increasesthe fluidityof the alloyanditalsoacts
as a deoxidiser.
8. Due to the presence of whichof the followingdoeswhitecastironappearwhite?
a) Pearlite
b) Ledeburite
c) Martensite
d) Cementite
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Answer:d
Explanation:Inwhite castiron,itappearsas a brokenwhite surface due tothe presence of
cementite whichisametastable phase.
9. In malleable castiron,the graphite turnsintospheroidal particles.
a) True
b) False
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Answer:a
Explanation:The above statementistrue.Inmalleablecastiron,the graphite turnsintospheroidal
particlesratherthanformingflakes.
10. What isthe formgraphite structure inductile castiron?
a) Spheroidal
b) Nodular
c) Flakes
d) Layers
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