Assertion: a : During hardening of steel, the component to be heat treated is strongly agitated in the quenching medium.
Reason : r : The agitation breaks down the vapour barrier allowing the quench to proceed at a more rapid rate.
A. Both 'a' and 'r' are correct but 'r' is not correct reason of 'a'
B. Both 'a' and 'r' are false
C. 'a' is true but 'r' is false
D. Both 'a' and 'r' are correct and 'r' is the correct reason for 'a'
Answer: Option B
This Question Belongs to Metallurgical Engineering >> Physical Metallurgy
A plastically deformed metal crystal at low temperature exhibits wavy slip line pattern due to
A. Dislocation pile-up
B. Large number of slip systems
C. Low stacking faultenergy
D. Dislocation climb
Which of the following microstructures of the eutectic is not observed in binary alloys?
A. Lamellar
B. Widmanstatten
C. Acicular
D. Nodular
Upon addition of sodium oxide to molten silicate slag, the viscosity of the slag
A. decreases because the oxygen ions supplied by the sodium oxide break the chain structure of the silicate slag
B. increases because the oxygen ion supplied by the sodium oxide further add to the oxygen network in the slag
C. remains unaffected because fundamentally one can not distinguish between the oxygen ions supplied by the sodium oxide and those already present in the slag
D. remains unaffected because the oxygen ions fill up the holes and vacancies present in the liquid slag
A. P-4, Q-3, R-2, S-1
B. P-1, Q-2, R-3, S-4
C. P-2, Q-4, R-1, S-3
D. P-2, Q-4, R-3, S-1
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