Machine Design Questions and Answers -Fits & Hot and Cold Working of Metals and Answers

Machine Design Interview Questions & Answers on “Fits & Hot and Cold Working of Metals”.

1. Which of the following is not a classification of fit?
a) Clearance
b) Transition
c) Interference
d) Enjoining
Answer: d
Clarification: Simple classification of fits is down in 3 categories.

2. Which of the following always provides a positive clearance between the hole and the shaft over the entire range of tolerances?
a) Clearance
b) Transition
c) Interference
d) None of the mentioned
Answer: a
Clarification: Clearance positive imparts a positive clearance.

3. In this case, tolerance zone of hole is entirely below that of the shaft.
a) Clearance
b) Interference
c) Enjoining
d) Non of the mentioned
Answer: b
Clarification: Interference fit provides a positive clearance and hence tolerance zone of hole is below that of shaft.

4. Which of the following are true for system of tolerances to the shaft and the hole?
a) In hole-basis system, various shafts are associated with a single hole
b) In hole-basis system as well as shaft-basis system, various shafts are associated with multiple holes
c) In shaft-basis system, various shafts are associated with a single hole
d) None of the mentioned
Answer: a
Clarification: As per the standards.

5. The description of tolerances consists of two parts namely?
a) Fundamental deviation and magnitude of tolerance
b) Magnitude of deviation and magnitude of tolerance
c) Mean deviation and magnitude of tolerance
d) Fundamental deviation and tolerance
Answer: a
Clarification: Fundamental deviation and magnitude of tolerance are decrypted in the tolerance.

6. Which of the following are true for fundamental deviation?
a) Gives location of tolerance zone
b) Capital letter is used for both holes and shafts
c) Small letter is used for both holes and shaft
d) None of the mentioned
Answer: a
Clarification: Tolerance zone is depicted by deviation while magnitude is depicted by grade.

7. How many grades of tolerances are there according to BIS system fits and tolerances?
a) 12
b) 14
c) 16
d) 18
Answer: d
Clarification: As per the standard.

8. Tolerance for a shaft of 50mm diameter as the basic size, with the fundamental deviation denoted by g and tolerance of grade 7 is represented as?
a) g50,7
b) 50g7
c) 7g50
d) None of the mentioned
Answer: b
Clarification: First fundamental deviation is written followed by diameter and grade.

9. The temperature at which new stress free grains are formed in the metal is called the ______ temperature.
a) Recrystallization
b) Crystallization
c) Solidification
d) None of the mentioned
Answer: a
Clarification: Definition of recrystallization temperature.

10. Hot working or cold working, which reduces strain hardening and residual stresses.
a) Hot working
b) Cold working
c) Both have equal effect
d) Impossible to detect
Answer: a
Clarification: In hot working grains are re arranges as per requirement and no residual stresses.

11. Hot rolled components have better toughness and ductility.
a) True
b) False
Answer: a
Clarification: Hot working refines grain structure an hence improves ductility and toughness.

12. Hot rolled components have better surface finish than cold rolled components.
a) True
b) False
Answer: b
Clarification: Cold working gives better surface finish.

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