1) In mottled cast iron, slow cooling rate is used to obtain ______
a. white cast iron
b. gray cast iron
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: gray cast iron
Explanation:
No explanation is available for this question!
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2) The gray cast iron has ____
a. high melting point
b. high thermal conductivity
c. low compressive strength
d. all of the above
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Answer
Explanation
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ANSWER: high thermal conductivity
Explanation:
No explanation is available for this question!
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3) What is the effect of silicon on the structure of cast iron?
1. Blowholes are present in the castings
2. Increases fluidity
3. Influences the solidification of liquid alloys
4. Reacts with iron to form iron sulphide
a. 1 and 2
b. 2 and 3
c. 3 and 4
d. All of the above
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Answer
Explanation
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ANSWER: 2 and 3
Explanation:
No explanation is available for this question!
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4) Nodules of graphite are observed in the microstructure of _______
a. white cast iron
b. malleable cast iron
c. spheroidal cast iron
d. all of the above
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Answer
Explanation
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ANSWER: spheroidal cast iron
Explanation:
No explanation is available for this question!
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5) Which of the following parameters is/are false for steel?
a. High carbon content
b. High melting point
c. Low damping capacity
d. None of the above
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Answer
Explanation
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ANSWER: High carbon content
Explanation:
No explanation is available for this question!
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6) What is the effect of increased carbon content on chilled cast iron?
a. Chilling depth increases
b. Hardness of chilled zone increases
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: Hardness of chilled zone increases
Explanation:
No explanation is available for this question!
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7) Which of the following elements increase/s chilled depth for chilled cast irons?
a. Silicon
b. Manganese
c. Manganese sulphide
d. All of the above
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Answer
Explanation
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ANSWER: Manganese sulphide
Explanation:
No explanation is available for this question!
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8) Rosettes of tempered carbon in the matrix of ferrite are observed in the microstructure of _____
a. gray cast iron
b. spheroidal cast iron
c. malleable cast iron
d. none of the above
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Answer
Explanation
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ANSWER: malleable cast iron
Explanation:
No explanation is available for this question!
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9) Which desulphurising agent is used to remove sulphur from iron during melting?
a. Calcium carbide
b. Sodium carbonate
c. Soda ash
d. All of the above
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Answer
Explanation
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ANSWER: All of the above
Explanation:
No explanation is available for this question!
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10) Why is gray cast iron annealed?
a. Graphitize carbide
b. Decrease ductility
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: Graphitize carbide
Explanation:
No explanation is available for this question!
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