Engineering Materials Practice Set-5

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1. Delta iron occurs at temperature of

Room temperature

Above melting point

Between 910°C and 1400°C

Between 1400°C and 1539°C

2. Closed packed hexagonal space lattice is found in

None of the above

Zinc, magnesium, cobalt, cadmium, antimony and bismuth

Gamma-iron, aluminium, copper, lead, silver and nickel

Alpha-iron, tungsten, chromium and molybdenum

3. In full annealing, the hypo eutectoid steel is heated from 30°C to 50°C above the upper critical temperature and then cooled

Any one of these

Slowly in the furnace

In still air

Suddenly in a suitable cooling medium

4. The molecules in a solid move

In circular motion

In a haphazard way

Back and forth like tiny pendulums

In a random manner

5. Slow plastic deformation of metals under a constant stress is known as

Plastic deformation

Creep

Fatigue

Endurance

6. Lead is poured into the joint between two pipes. These pipes may be made of

Vitrified clay

Concrete

Cast iron

Asbestos cement

7. Foundry crucible is made of

Lead

Mild steel

Graphite

German silver

8. Tin base white metals are used where the bearings are subjected to

Light load and pressure

Large surface wear

High pressure and load

Elevated temperatures

9. Malleability of a material can be defined as

Ability to undergo large permanent deformations in tension

Ability to undergo large permanent deformations in compression

All of the above

Ability to recover its original form

10. Neutral solution is one which has pH value

Less than 7

Equal to 7

pH value has nothing to do with neutral solution

Greater than 7

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11. Which of the following display properties similar to that of steel?

(A) Blackheart cast iron

(D) None of these

(B) Whiteheart cast iron

(C) Both (A) and (B)

12. Materials after cold working are subjected to following process to relieve stresses

Hot working

Normalizing

Tempering

Annealing

13. White cast iron has

High compressive strength

Carbon in the form of carbide

Low tensile strength

All of these

14. Iron-carbon alloys containing 1.7 to 4.3% carbon are known as

Hypereutectic cast irons

None of these

Hypoeutectic cast irons

Eutectic cast irons

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

Shot peening

Cold working

Nitriding of surface

Surface decarburisation

16. The ultimate tensile strength of low carbon steel by working at a high strain rate will

Remain constant

Decrease

Increase

First increase and then decrease

17. The charge is fed into the blast furnace through the

Throat

Stack

Bosh

Tyres

18. Which of the following metal is used in making electrical resistance wire for electric furnaces and heating elements?

Nichrome

Phosphor bronze

Monel metal

Babbitt metal

19. Balls for ball bearings are made of

Stainless steel

Cast iron

Mild steel

Carbon-chrome steel

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

Silicon and manganese has burnt and carbon has started oxidizing

Air is burning out silicon and manganese

The brown smoke does not occur during the operation of a Bessemer converter

The converter must be titled to remove the contents of the converter

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21. The ability of a material to resist softening at high temperature is known as

Creep

Hot tempering

Fatigue

Hot hardness

22. The steel widely used for motor car crankshafts is

Silicon steel

Chrome steel

Nickel steel

Nickel-chrome steel

23. The coordination number of a face centered cubic space lattice is

Twelve

Twenty

Eighteen

Six

24. Following elements have face-centered cubic structure

A iron (below 910°C and between 1400 to 1539°C), W

Gamma iron (910° to 1400°C), Cu, Ag, Au, Al, Ni, Pb, Pt

All of the above

Mg, Zn, Ti, Zr, Br, Cd

25. Mild steel belongs to the following category

High carbon steel

Low carbon steel

Alloy steel

Medium carbon steel

26. The property of a material essential for spring materials is

Resilience

Ductility

Plasticity

Stiffness

27. When elements like nickel, chromium, copper and molybdenum are added to the molten cast iron, it produces

White cast iron

Alloy cast iron

Nodular cast iron

Malleable cast iron

28. The type of space lattice found in alpha-iron is

Close packed hexagonal space lattice

None of these

Face centered cubic space lattice

Body centered cubic space lattice

29. The elastic stress strain behavior of rubber is

Plastic

Linear

No fixed relationship

Nonlinear

30. Which is false statement about case hardening? Case hardening is done by

Electroplating

Induction hardening

Cyaniding

Nitriding

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31. The percentage of carbon in low carbon steel is

0.5%

0.3%

0.05%

0.15%

32. Recrystallization temperature is one

At which change of allotropic form takes place

At which crystals grow bigger in size

At which crystals first start forming from molten metal when it is cooled

At which new spherical crystals first begin to form from the old deformed one when a strained metal is heated

33. A small percentage of boron is added to steel in order to

Increase wear resistance

Increase hardenability

Reduce machinability

Increase endurance strength

34. Which is false statement about properties of aluminium?

Modulus of elasticity is fairly low

Wear resistance is very good

Creep strength limits its use to fairly low temperatures

Fatigue strength is not high

35. Isotropic materials are those which have the same

Electric and magnetic properties in all directions

Thermal properties in all directions

Elastic properties in all directions

Stresses induced in all directions

36. Brass is an alloy of

Copper and tin

Copper, tin and zinc

None of these

Copper and zinc

37. A material is known as allotropic or polymorphic if it

Has a fixed structure under all conditions

Exists in several crystal forms at different temperatures

Has its atoms distributed in a random pattern

Responds to heat treatment

38. When low carbon steel is heated up to lower critical temperature

The grain size first increases and then decreases very rapidly

The average grain size is a minimum

There is no change in grain size

The grain size increases very rapidly

39. Which of the following constituents of steels is softest and least strong?

Pearlite

Cementite

Austenite

Ferrite

40. The stiffness is the ability of a material to resist

Fracture due to high impact loads

Deformation under stress

None of the above

Externally applied forces with breakdown or yielding

Engineering Materials Practice Set-5

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