This set of Metal Forming Multiple Choice Questions & Answers (MCQs) focuses on “Cooling Curve for Pure Iron”.
1. What is the melting point of pure iron?
a) 1500°C
b) 1535°C
c) 1570°C
d) 1605°C
View Answer
Explanation: Iron exists in many allotropic forms, and every such allotropic form has a different melting, boiling and solidifying point. But, for pure iron, the melting point is 1535°C.
2. Which iron is formed when the melt is frozen?
a) Alpha
b) Beta
c) Gamma
d) Delta
View Answer
Explanation: Alpha irons, beta irons or gamma irons cannot be formed when the metal is in the frozen form. When the molten metal is frozen, delta iron is formed.
3. What is the kind of lattice in a delta iron?
a) Face centered cubic
b) Body centered cubic
c) Hexagonal closely packed
d) Tetragonal closely packed
View Answer
Explanation: The delta form of solid state of iron, which is formed on cooling the melt, has a body centered cubic lattice structure.
4. What is the kind of lattice in a gamma iron?
a) Face centered cubic
b) Body centered cubic
c) Hexagonal closely packed
d) Tetragonal closely packed
View Answer
Explanation: The gamma form of solid state of iron, which is formed on cooling the melt, has a face centered cubic lattice structure.
5. In transformation in steel, hypo eutectoid steel are heated up to what temperature?
a) 677°C
b) 700°C
c) 723°C
d) 746°C
View Answer
Explanation: In transformation in steel, the hypo eutectoid steels are heated up to a very high amount of temperature. The temperature to which they are taken is 723°C.
6. What is the Brinell hardness of pearlite?
a) 150
b) 180
c) 210
d) 240
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Explanation: Pearlite is not the hardest form. The Brinell hardness of pearlite is only 180. There is a harder material than pearlite, called as martensite, which has Brinell hardness ranging from 650-700.
7. The alpha iron is highly non-magnetic.
a) True
b) False
View Answer
Explanation: It is one of the properties of alpha irons that alpha irons are highly magnetic and they are found to exist only at room temperature. The alpha iron is the fourth retardation of iron.
8. How much is the Brinell hardness of martensite?
a) 600-650
b) 650-700
c) 750-800
d) 800-850
View Answer
Explanation: Martensite is a ferro-magnetic substance in nature, and it is known to have Brinell hardness ranging from 650-700.
9. What is the value of ‘a’ in a delta iron lattice?
a) 2.00 Å
b) 2.93 Å
c) 4.00 Å
d) 4.93 Å
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Explanation: The value of a, which is the distance between two consecutive atoms in the lattice, in delta iron lattice is calculated to be 2.93 Å, which is around 2.93 x 10-10 meters.
10. Alpha iron exists only in high temperature and pressure conditions.
a) True
b) False
View Answer
Explanation: It is one of the properties of alpha irons that alpha irons are highly magnetic and they are found to exist only at room temperature.
Sanfoundry Global Education & Learning Series – Metal Casting, Forming and Welding.
To practice all areas of Casting, Forming and Welding, here is complete set of 1000+ Multiple Choice Questions and Answers.
