# Test: Plain Carbon Steel, Iron Carbon Equilibrium Diagram & Cast Iron - 2

## 30 Questions MCQ Test RRB JE for Mechanical Engineering | Test: Plain Carbon Steel, Iron Carbon Equilibrium Diagram & Cast Iron - 2

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Attempt Test: Plain Carbon Steel, Iron Carbon Equilibrium Diagram & Cast Iron - 2 | 30 questions in 90 minutes | Mock test for Mechanical Engineering preparation | Free important questions MCQ to study RRB JE for Mechanical Engineering for Mechanical Engineering Exam | Download free PDF with solutions
QUESTION: 1

### Consider the following statements about medium carbon steel:   1. It can be quench-hardened but not case-hardened. 2. It cannot be quench-hardened but case-hardening can be done. 3. It exhibits distinct yield point under tension test. Which of the following statements given above are correct?

Solution:

Ans. (c) Low carbon steels (less than 0.3%C) cannot be quench hardened but case hardening can be done.

QUESTION: 2

Solution:

Ans. (d)

QUESTION: 3

### In case of power screws, what is the combination of materials used for the screwand the nut? I

Solution:

Ans. (b)

QUESTION: 4

Hot cracks occur in the weld and fusion zone as the metal solidifies. Which of thefollowing are the causes for hot cracks?
1. Presence of sulphur and phosphorus in the base metal
2. High carbon or alloy content of the base metal
3. Moisture in the joint or electrode4. Joint restraint
Select the correct answer using the code given below:

Solution:

Ans. (d)

QUESTION: 5

Which of the following factors influence in a plain carbon steel?
1. Percentage carbon
2. Quenching media
3. Work size
Select the correct answer using the code given below:

Solution:
QUESTION: 6

Match the terms used in connection with heat-treatment of steel with the micro structural/physical characteristics:

Codes: A B C D                A B C D

Solution:
QUESTION: 7

A cast iron specimen in a torsion test gives a

Solution:

Ans. (b) cast iron brittle fracture.

QUESTION: 8

Which of the following metal shrinks most from molten state to solid state?

Solution:

Admiralty metal is an alloy of not less than 70 percent copper, about 1 percent tin, small amounts of other elements, and the balance zinc; tin brass.
Admiralty metal shrinks most from molten state to solid state

QUESTION: 9

Which of the following pairs are correctly matched?
1. Lead screw nut………… Phosphor bronze
2. Piston………….. Cast iron.
3. Cam ……………………..EN-31 steel
Select the correct answer using the codes given below:
Codes:

Solution:

Ans. (d)

QUESTION: 10

Addition of magnesium to cast iron increases its

Solution:

Ans. (b)

QUESTION: 11

Consider the following work materials:
1. Titanium
2. Mild steel
3. Stainless steel
4. Grey cast iron.
The correct sequence of these materials in terms of increasing order of difficulty inmachining is

Solution:

Ans. (a) Titanium high cost and need 10 times much energy than steel to produce.
Light weight, strong, corrosion resistant, properties between steel and aluminium.

QUESTION: 12

Assertion (A): Machine tool beds are generally made of grey cast iron.Reason (R): Cast iron possesses good self-lubricating properties.

Solution:

Ans. (a) Both A and R are true and R provides correct explanation for A.

QUESTION: 13

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

Solution:

Ans. (b)

QUESTION: 14

Assertion (A): The notch sensitivity of cast iron component is zero.Reason (R): Cast iron does not have a yield point.

Solution:

Ans. (a)

*Multiple options can be correct
QUESTION: 15

Cast iron is used for machine beds because of its high

Solution:
QUESTION: 16

Piston compression rings are made of which one of the following

Solution:

Ans.(a) They are subjected to wear, to minimize they are made of wear resisting material, high quality grey cast iron casting and coated with Nitride or Chrome by PVD.

QUESTION: 17

Which of the following pairs are correctly matched?
(Designation of Steel/Cast Iron)     (Description)
1. Fe E 250                                  : Minimum tensile strength of 250 N/mm2
2. 40 C 8                                      : Percentage of Manganese is 0.7% - 0.9%
3. FG 200                                    : Grey cast iron with ultimate tensile strength of200 N/mm2
Select the correct answer using the code given below:

Solution:

Ans. (c)

QUESTION: 18

Vibration damping in machinery is best achieved by means of base structuresmade of which one of the following materials?

Solution:

Ans. (c) Carbon is in a flake like shape as in grey cast iron; the graphite breaks up the
continuity of iron and greatly weakens it. But it also helps in absorbing vibrational energy,
as a result of which grey cast iron is normally used for the beds of machine tools.

QUESTION: 19

Which one of the following cast irons consists of carbon in rosette form?

Solution:

Ans. (d)

QUESTION: 20

The percentage of carbon in gray cast iron is in the range of

Solution:

Ans. (c)

QUESTION: 21

Which of the following materials is used in the manufacture of extrusion nozzles?

Solution:

Ans. (c)

QUESTION: 22

Martensite is a super-saturated solution of carbon in

Solution:

Ans. (a)

QUESTION: 23

Increase of ferrite phase in steel increases:

Solution:

Ans. (a)

QUESTION: 24

Martensite is a super-saturated solution of carbon in

Solution:

Ans. (a)

QUESTION: 25

A given steel test specimen is studied under metallurgical microscope.Magnification used is 100 X. In that different phases are observed. One of them isFe3C. The observed phase Fe3C is also known as

Solution:

Ans. (b)

QUESTION: 26

Which one of the following is the correct statement?
Pearlite in iron-carbon system is a

Solution:

Ans. (b) Since the chemical separation occurs entirely within crystalline solids, the
resultant structure is a five mechanical mixture of ferrite & cementite.
Pearlite is a eutectoid mixture of ferrite and cementite.

QUESTION: 27

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

Solution:

Ans. (b)

QUESTION: 28

In a eutectic system, two elements are completely

Solution:

Ans. (b) In eutectic system, two elements are completely soluble in liquid state.

QUESTION: 29

For the pipe fitting like elbow, tee, union etc. which of the following is preferred?

Solution:

Ans. (b)

QUESTION: 30

Presence of hydrogen in steel causes

Solution:

The result of hydrogen embrittlement is that components crack and fracture at stresses less than the yield strength of the metal.

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