250+ TOP MCQs on Transformation in Steel and Answers

Casting, Forming and Welding Multiple Choice Questions on “Transformation in Steel”.

1. Which of the following processes is called as quenching?
a) Slow cooling
b) Slow heating
c) Rapid cooling
d) Rapid heating

Answer: c
Clarification: Among the following, that is, slow cooling, slow heating, rapid cooling and rapid heating, quenching is the name given to the process of rapid cooling.

2. On martensite formation, what is the percentage increase in the volume of the steel?
a) 3%
b) 13%
c) 23%
d) 33%

Answer: a
Clarification: It has been observed that whenever there is a formation of martensite, there is some amount of increase in the volume accompanied by it. This increase in the volume is about 3%.

3. How much is the Brinell hardness of sorbite?
a) 250
b) 350
c) 450
d) 550

Answer: b
Clarification: The cementite in sorbite is known to be very finely divided. The material sorbite is not one of the hardest materials known in casting. The Brinell hardness of sorbite is 350.

4. How much is the Brinell hardness of troostite?
a) 250
b) 350
c) 450
d) 550

Answer: c
Clarification: The cementite in the troostite is very finely divided. The material troostite is not one of the hardest materials known in casting. The Brinell hardness of sorbite is 450.

5. What is the chemical formula of cementite?
a) Fe₃O₄
b) Fe₂O₃
c) Fe₃C
d) FeSO₄

Answer: c
Clarification: None.

6. What is the crystal structure of cementite?
a) Orthogonal
b) Pyramidal
c) Trapeziodal
d) Orthorhombic

Answer: d
Clarification: The crystal structure of the compound cementite or iron carbide is not orthogonal or pyramidal or trapezoidal, but it is orthorhombic.

7. What is the curie temperature of cementite?
a) 480K
b) 500K
c) 520K
d) 540K

Answer: a
Clarification: The compound cementite is also called as Iron Carbide. The chemical formula of the compound cementite is Fe3C. The curie temperature of the compound cementite is approximately about 480K.

8. What is the percentage weight of iron in cementite?
a) 93.3%
b) 94.3%
c) 95.3%
d) 96.3%

Answer: a
Clarification: In the compound iron carbide or cementite, the percentage weight of iron is 93.3% and the rest of the space in the lattice is occupied by carbon. By weight, carbon is present in about 6.67% in the mixture.

9. What is the percentage weight of carbon in cementite?
a) 5.53%
b) 6.67%
c) 7.23%
d) 8.39%

Answer: b
Clarification: None.

10. Cementite is a brittle material.
a) True
b) False

Answer: a
Clarification: Cementite, when in its purest form, is used as a ceramic. Cementite or iron carbide is considered to be a brittle material.