Machine Design Questions and Answers - Ceramics & Plastics

1. Is it possible to completely relieve the residual stresses in a cast steel product?
a) True
b) False

Answer: b
Explanation: Solidification results in great amount of residual stresses.

2. Poor fluidity and contraction are compulsory to be taken into consideration while designing a cast steel product.
a) True
b) False

Answer: a
Explanation: Contraction affects to quite a extent in cast steel.

3. In alloy 4450, 2nd digit represents?
a) average percentage of major alloying elements, halved and rounded off
b) average percentage of major alloying elements
c) average percentage of minor alloying elements, halved and doubled
d) average percentage of minor alloying elements

Answer: a
Explanation: Second digit is used to represent major alloying element.

4. In alloy 4450, 4 represents?
a) Silicon
b) Aluminium
c) Manganese
d) Zinc

Answer: a
Explanation: In alloy nomenclature,1=Al;2=Cu;3=Mn;4=Si;5=Mg

5. An aluminium alloy casting with 9.8% Cu, 1.0% Fe and 0.25% Mg
a) Alloy 2585
b) Alloy 3586
c) Alloy 2686
d) Alloy 3584

Answer: a
Explanation: 1st digit=2(Copper) ; 2nd digit=9.8/2=5 ;3rd digit=8(Iron); 4th digit=5(Magnesium).

6. Ceramics consist of
a) ionic & covalent bonding
b) covalent bonding
c) hydrogen bonding
d) none of the mentioned

Answer: a
Explanation: Ceramics consists of ionic and covalent bonds only.There is no hydrogen compound so no case of H boding.

7. All ceramics contain clay.
a) True
b) False

Answer: b
Explanation: No this may sound convincing but all ceramics don’t contain clay.

8. The densities of ceramics are low.
a) True
b) False

Answer: a
Explanation: In ceramics, different oxides and carbides are not compactly bonded.

9. There are small voids in ceramics structure.
a) True
b) False

Answer: a
Explanation: Compounds are less compactly bonded and hence voids are formed.

10. Which of the following properties are true for ceramics.
a) light weight construction with low inertia force
b) excellent wear
c) lower friction loss
d) all of the mentioned

Answer: d
Explanation: Properties of ceramics.