Engineering Materials Practice Set-3

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1. The unit cells

Contain the smallest number of atoms which when taken together have all the properties of the crystals of the particular metal

May be defined as the smallest parallelepiped which could be transposed in three coordinate directions to build up the space lattice

Have the same orientation and their similar faces are parallel

All of the above

2. The ability of a material to resist fracture due to high impact loads, is called

Strength

Brittleness

Toughness

Stiffness

3. Which is false statement about normalizing? Normalizing is done to

Induce stresses

Reduce segregation in casting

Improve mechanical properties

Refine grain structure

4. There are fourteen atoms in a unit cell of

None of these

Body centered cubic space lattice

Face centered cubic space lattice

Close packed hexagonal space lattice

5. Hematite iron ore contains iron about

70%

30%

55%

45%

6. If a refractory contains high content of silicon, it means refractory is

Neutral

Brittle

Acidic

Basic

7. Taps dies and drills contain carbon

Below 1%

Below 0.5%

Above 2.2%

Above 1%

8. The surface hardness of the following order is achieved by nitriding operation

1000 to 1100 VPN

600 VPN

1500 VPN

250 VPN

9. The coke in the charge of blast furnace

Acts as an iron bearing mineral

Forms a slag by combining with impurities

Controls the grade of pig iron

Supplies heat to reduce ore and melt the iron

10. According to Indian standard specifications, plain carbon steel designated by 40 C8 means that the carbon content is

0.04%

0.4 to 0.6%

0.35 to 0.45%

0.6 to 0.8%

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11. In low carbon steels, presence of small quantities of sulphur improves

Hardenability

Formability

Machinability

Weldability

12. The tensile strength of wrought iron is maximum

None of the above

Along the lines of slag distribution

Perpendicular to lines of slag distribution

Uniform in all directions

13. Which of the following represents the allotropic forms of iron?

Body centered cubic iron and face centered cubic iron

Alpha iron, beta iron and gamma iron

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

14. Tungsten in steel

Improves wear resistance, cutting ability and toughness

Improves cutting ability and reduces hardenability

Gives ductility, toughness, tensile strength and anti-corrosion properties

Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties

15. Which of the following property is desirable in parts subjected to shock and impact loads?

Stiffness

Brittleness

Toughness

Strength

16. The aluminium alloy made by melting aluminium with 2 to 10% magnesium and 1.75% copper is called

Duralumin

Hindalium

Magnalium

Y-alloy

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

Vanadium, chromium, tungsten

Chromium, titanium, vanadium

Tungsten, chromium, titanium

Tungsten, titanium, vanadium

18. The portion of the blast furnace below its widest cross-section is called

Hearth

Stack

Bosh

Throat

19. Large forgings, crank shafts, axles normally contain carbon up to

0.55 to 1.0%

0.05 to 0.20%

0.45 to 0.55%

0.20 to 0.45%

20. Ductility of a material can be defined as

Ability to recover its original form

Ability to undergo large permanent deformations in tension

Ability to undergo large permanent deformations in compression

All of the above

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21. In compression, a prism of brittle material will break

By shearing along oblique plane

By crushing into thousands of pieces

By forming a bulge

In direction perpendicular to application of load

22. A specimen of aluminium metal when observed under microscope shows

H.C.P. structure

B.C.C. crystalline structure

F.C.C. crystal structure

A complex cubic structure

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

Plasticity

Ductility

Brittleness

Malleability

24. Which of the following elements does not impart hardness to steel?

Chromium

Copper

Silicon

Nickel

25. Cementite consist of

13% ferrite and 87% cementite

13% carbon and 87% ferrite

13% cementite and 87% ferrite

6.67% carbon and 93.33% iron

26. Points of arrest for iron correspond to

Stages at which properties do not change with increase in temperature

There is nothing like points of arrest

Stages at which allotropic forms change

Stages at which further heating does not increase temperature for some time

27. Which of the following property is desirable for materials used in tools and machines?

Elasticity

Plasticity

Ductility

Malleability

28. Corundum contains more than 95%

Al₂O₃

MgO

Steel

SiO₂

29. Cobalt in steel

Improves cutting ability and reduce hardenability

Improves wear resistance, cutting ability and toughness

Gives ductility, toughness, tensile strength and anti corrosion property

Refines grain size and produces less tendency to carburisation, improve corrosion and heat resistant proper ties

30. Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio

30 : 20 : 30 : 20

50 : 20 : 10 : 20

50 : 20 : 20 : 10

40 : 30 : 20 : 10

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31. The defect which takes place due to imperfect packing of atoms during crystallization is known as

Point defect

Surface defect

None of these

Line defect

32. Brass contains

90% copper and 10% tin

70 - 75% copper and rest tin

70% copper and 30% zinc

85 - 92% copper and rest tin with little lead and nickel

33. Which of the following statement is incorrect about duralumin?

It is prone to age hardening

It is lighter than pure aluminium

It can be forged

It has good machining properties

34. The machinability of steel is improved by adding

Chromium

Nickel

Nickel and chromium

Sulphur, lead and phosphorus

35. Gamma-iron occurs between the temperature ranges of

400°C to 600°C

900°C to 1400°C

600°C to 900°C

1400°C to 1530°C

36. The hardness of steel primarily depends on

Heat treatment employed

Percentage of alloying elements

Percentage of carbon

Shape of carbides and their distribution in iron

37. The usual composition of a soldering alloy is

Tin and copper

Tin, lead and small percentage of antimony

Tin, lead and silver

Tin and lead

38. The metal suitable for bearings subjected to heavy loads, is

Monel metal

White metal

Silicon bronze

Phosphor bronze

39. The percentage of carbon in grey iron castings usually varies between

0.5 to 1%

1.2%

2.5 to 4.5%

5 to 7%

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

Brass

Admiralty metal

Cast steel

Cast iron

Engineering Materials Practice Set-3

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