This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Cast Irons”.
1. Which of the following can be carbon composition of cast iron?
a) 1%
b) 1.5%
c) 0.5%
d) 2.5%
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Explanation: The carbon composition in cast iron is more than 2% and hence only 2.5% can be correct answer as all the answer lie outside the range.
2. Cast iron tends to be brittle.
a) True
b) False
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Explanation: The above statement is correct. Cast iron tends to be brittle because of the presence of a high amount of carbon in it.
3. At what temperature does pure iron turn into FCC structure?
a) 800 °C
b) 900 °C
c) 910 °C
d) 810 °C
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Explanation: Pure iron turns into its FCC structure at a temperature of 910 °C. This structure is called gamma iron or γ-iron.
4. Which of the following alloying element forces the carbon out of the solution?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Explanation: Silicon is used in a cast iron to bring out the carbon from the solution. If a large amount silicon is added grey cast iron is formed.
5. Which of the following alloying element increase hardness?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Explanation: The presence of sulfur increase the hardness of the alloy by reacting with iron to form iron sulphide.
6. Which of the following alloying element refines pearlite structure?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Explanation: Nickel is the most common alloying element in cast iron. It helps in refining the pearlite and graphite structure.
7. Which of the following alloying element is added as a degasser?
a) Silicon
b) Sulphur
c) Nickel
d) Titanium
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Explanation: Titanium is added as a degasser and it increases the fluidity of the alloy and it also acts as a deoxidiser.
8. Due to the presence of which of the following does white cast iron appear white?
a) Pearlite
b) Ledeburite
c) Martensite
d) Cementite
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Explanation: In white cast iron, it appears as a broken white surface due to the presence of cementite which is a metastable phase.
9. In malleable cast iron, the graphite turns into spheroidal particles.
a) True
b) False
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Explanation: The above statement is true. In malleable cast iron, the graphite turns into spheroidal particles rather than forming flakes.
10. What is the form graphite structure in ductile cast iron?
a) Spheroidal
b) Nodular
c) Flakes
d) Layers
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Explanation: The graphite structure of a ductile cast iron is nodular form and it is seen as tiny nodules with graphite in layers forming the nodules.
Sanfoundry Global Education & Learning Series – Materials Science.
To practice all areas of Materials Science, here is complete set of 1000+ Multiple Choice Questions and Answers.