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# Test: Equilibrium Diagrams & Phase Changes - 3

## 30 Questions MCQ Test Engineering Materials | Test: Equilibrium Diagrams & Phase Changes - 3

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This mock test of Test: Equilibrium Diagrams & Phase Changes - 3 for Mechanical Engineering helps you for every Mechanical Engineering entrance exam. This contains 30 Multiple Choice Questions for Mechanical Engineering Test: Equilibrium Diagrams & Phase Changes - 3 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Equilibrium Diagrams & Phase Changes - 3 quiz give you a good mix of easy questions and tough questions. Mechanical Engineering students definitely take this Test: Equilibrium Diagrams & Phase Changes - 3 exercise for a better result in the exam. You can find other Test: Equilibrium Diagrams & Phase Changes - 3 extra questions, long questions & short questions for Mechanical Engineering on EduRev as well by searching above.
QUESTION: 1

### Free carbon in iron makes the iron

Solution:

Hyper eutectoid steel ⇒ 0.76 to 2.1 percent carbon.

QUESTION: 2

Solution:
QUESTION: 3

### The structure of austenite is

Solution:
QUESTION: 4

In a eutectic system, two elements are completely

Solution:
QUESTION: 5

During peritectic solidification, one liquid

Solution:

Eutectic system implies two solid completely soluble in liquid system and insoluble in solid state

QUESTION: 6

Increase of ferrite phase in steel increases

Solution:

Peritectic reaction

QUESTION: 7

The eutectoid of carbon in iron, above lower critical temperature, when cooled, result in

Solution:

The correct answer should be the second option - Ferrite and Cementite.

A eutectoid reaction is referred to the phase transformation or change of one solid into two other different solids.

Eutectoid reaction occurs at the eutectoid point of 727°C and 0.77% Carbon, which when cooled gives α-Ferrite and Cementite, also known as Pearlite. Below the critical temperature of 723°C, austenite is no more stable and it gets converted into pearlite.

QUESTION: 8

Pearlite  is a combination of

Solution:
QUESTION: 9

If a particular Fe-C alloy contains less than 0.83% carbon. It is called

Solution:

Plain carbon steels in which carbon percentage is less than 0.8% are called hypo-eutectoid steel.

QUESTION: 10

Hyper eutectoid steels have structure of

Solution:
QUESTION: 11

Austenite is a solid solution of carbon in

Solution:
QUESTION: 12

Cementite consists of

Solution:

Cementite consist of 6.67% carbon and 93.33% iron It has an orthorhombic crystal structure

QUESTION: 13

Delta iron occur between the temperature range of

Solution:
QUESTION: 14

A material is said to be allotropic. If it has

Solution:
QUESTION: 15

In iron-carbide diagram, pearlite is

Solution:
QUESTION: 16

Match List-I (Name of material) with List-II (% Carbon Range) and select the correct answer using the codes given below the lists:
List-I
A. Hypoeutectoid steel
B. Hypereutectoid steel
C. Hypoeutectic cast iron
D. Hypereutectic cast iron
List-II
1. 4.3 — 6.67
2. 2.0 — 43
3. 0.8 — 2.0
4. 0.008 — 0.8
Codes:
A B C D
(a) 4 3 2 1
(b) 1 3 4 2
(c) 4 1 2 3
(d) 1 2 3 4

Solution:
QUESTION: 17

For good weldability, the carbon equivalent (%) of steel should be in the range of

Solution:

Hypo eutectoid steel 0.008 - 0,76
Hyper eutectoid steel 0.76 - 2.1
Hypo eutectic steel 2.1 - 4.3
Hyper eutectic steel 4.3 - 6.64

QUESTION: 18

Match List-I (Fe - Fe3 C Phase Diagram characteristic) with List-II (Phase) and select the correct answer using the codes given below the lists:
List-I
A. Alpha (α) iron
B. Iron carbide having crystal lattice
C. BCC pure allotropy of iron is stable between 1388°C and its melting point at 1535°C.
List-II
1. δ iron
2. Eutectic with 3 iron and 1 carbon atom
3. Ferrite stable between 1388°C
4. Cementite
Codes
A B C
(a) 4 2 3
(b) 3 4 1
(c) 4 2 1
(d) 3 1 2

Solution:
QUESTION: 19

As per Gibb's phase rule, if number of components is equal to 2 then the number of phases will be

Solution:
QUESTION: 20

The eutectoid of carbon in iron, above lower critical temperature, when cooled, result in

Solution:

The correct answer should be the second option - Ferrite and Cementite.

A eutectoid reaction is referred to the phase transformation or change of one solid into two other different solids.

Eutectoid reaction occurs at the eutectoid point of 727°C and 0.77% Carbon, which when cooled gives α-Ferrite and Cementite, also known as Pearlite. Below the critical temperature of 723°C, austenite is no more stable and it gets converted into pearlite.

QUESTION: 21

Eutectic composition of iron-carbon alloy always corresponds to its

Solution:
QUESTION: 22

As the weight percentage of carbon increases in plain carbon steel, its

Solution:
QUESTION: 23

In peritectoid reaction on cooling, we get one solid phase from

Solution:
QUESTION: 24

Consider the following lead-tin phase diagram given below:

For which one of the following alloy compositions, the alloy wiil have the iowest melting point at 185°C?

Solution:
QUESTION: 25

Which one of the following sets of constituents is expected in equilibrium cooling of a hypereutectoid steel from austenitic state?

Solution:

Hypereutectoid steel when cooled in equilibrium will result in proeutectoid cementite and pearlite whereas hypoeutectoid steel when cooled in equilibrium will result in proeutectoid ferrite and pearlite.

QUESTION: 26

A given steel test specimen is studied under metallurgical microscope. Magnification used is 100 X. In that different phases are observed. One of them is Fe3C.

Solution:

Cementite has Fe3C composition, inter metallic compound.

QUESTION: 27

Which one of the following is the correct statements?

Solution:

The mechanical mixture of ferrite and cementite at room temperature is called pearlite, due to its pearly appearance under the optical microscope.

QUESTION: 28

Which one of the following elements is a ferritic stabilizer?

Solution:

Chromium, Tungsten and Molybdenum are ferritic stabilizer.

QUESTION: 29

Seasonal cracking is observed in

Solution:

Season cracking results from the combined effects of corrosion and internal stresses. The term seasonal cracking is usually applied to stress corrosion cracking of brass.

QUESTION: 30

Age hardening is employed for

Solution: