Engineering Materials MCQ Questions & Answers

11

In grey cast iron, carbon is present in the form of

A) Cementite B) Free carbon C) Flakes D) Spheroids

Discuss

Answer & Solution

Answer: Option C

Solution:

In grey cast iron, carbon is present in the form of Flakes

12

In malleable iron, carbon is present in the form of

A) Cementite B) Free carbon C) Flakes D) Nodular aggregates of graphite

Discuss

Answer & Solution

Answer: Option D

Solution:

In malleable iron, carbon is present in the form of Nodular aggregates of graphite

13

Nodular iron has

A) High machinability B) Low melting point C) High tensile strength D) All of the above

Discuss

Answer & Solution

Answer: Option D

Solution:

nodular iron, obtains its special properties through the addition of magnesium into the alloy.
The presence of magnesium causes the graphite to form in a spheroid shape as opposed to the flakes of gray iron.
Composition control is very important in the manufacturing process. Small amounts of impurities such as sulfur and oxygen react with the magnesium, affecting the shape of the graphite molecules.
Different grades of ductile iron are formed by manipulating the microcrystalline structure around the graphite spheroid.
This is achieved through the casting process, or through heat treatment, as a downstream processing step.

14

Nickel in steel

A) Improves wear resistance, cutting ability and toughness B) Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties C) Improves cutting ability and reduces hardenability D) Gives ductility, toughness, tensile strength and anti-corrosion properties

Discuss

Answer & Solution

Answer: Option D

Solution:

Nickel in steel Gives ductility, toughness, tensile strength and anti-corrosion properties.

15

Dislocations in materials refer to the following type of defect

A) Point defect B) Line defect C) Plane defect D) Volumetric defect

Discuss

Answer & Solution

Answer: Option B

Solution:

Dislocations in materials refer to Line defect.
Line defects are lines along which whole rows of atoms in a solid are arranged anomalously.
The resulting irregularity in spacing is most severe along a line called the line of dislocation.
Line defects can weaken or strengthen solids.

16

The main alloying elements high speed steel in order of increasing proportion are

A) Vanadium, chromium, tungsten B) Tungsten, titanium, vanadium C) Chromium, titanium, vanadium D) Tungsten, chromium, titanium

Discuss

Answer & Solution

Answer: Option A

Solution:

: High-speed steel (HSS) is an alloy known for its high hardness and resistance to abrasion, making it ideal for cutting tools. The main alloying elements are added in specific proportions to achieve these properties.

Vanadium is present in the smallest proportion among the three listed elements, followed by chromium, and then tungsten in the highest proportion.

Vanadium improves the wear resistance and hardness.

Chromium enhances the toughness and corrosion resistance.

Tungsten increases the hardness, hot hardness, and wear resistance of the steel.

17

Induction hardening is basically a

A) Carburising process B) Surface hardening process C) Core hardening process D) None of these

Discuss

Answer & Solution

Answer: Option B

Solution:

Induction hardening is a type of surface hardening in which a metal part is induction-heated and then quenched.
The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part.

18

Which of the following is not the correct method of increasing fatigue limit?

A) Shot peening B) Nitriding of surface C) Cold working D) Surface decarburisation

Discuss

Answer & Solution

Answer: Option D

Solution:

Decarburization is a surface degradation phenomenon in the forging and heat treating of steels.

19

The property of a material which enables it to retain the deformation permanently, is called

A) Brittleness B) Ductility C) Malleability D) Plasticity

Discuss

Answer & Solution

Answer: Option D

Solution:

plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces.

20

The brown smoke during the operation of a Bessemer converter indicates that the

A) Air is burning out silicon and manganese B) Silicon and manganese has burnt and carbon has started oxidizing C) The converter must be titled to remove the contents of the converter D) The brown smoke does not occur during the operation of a Bessemer converter

Discuss

Answer & Solution

Answer: Option A

Solution:

The brown smoke during the operation of a Bessemer converter indicates that the Air is burning out silicon and manganese

Engineering Materials MCQ Questions & Answers | Mechanical Engineering