Engineering Materials Practice Set-3

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

Formability

Machinability

Hardenability

Weldability

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

Brittleness

Malleability

Plasticity

Ductility

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

Hearth

Stack

Throat

Bosh

4. Corundum contains more than 95%

Steel

SiO₂

MgO

Al₂O₃

5. Tungsten in steel

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

Improves cutting ability and reduces hardenability

Improves wear resistance, cutting ability and toughness

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

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

Y-alloy

Magnalium

Duralumin

Hindalium

7. Ductility of a material can be defined as

All of the above

Ability to undergo large permanent deformations in tension

Ability to undergo large permanent deformations in compression

Ability to recover its original form

8. The usual composition of a soldering alloy is

Tin and lead

Tin, lead and small percentage of antimony

Tin, lead and silver

Tin and copper

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

Brittleness

Strength

Stiffness

Toughness

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

Brittleness

Stiffness

Toughness

Strength

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11. 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

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

5 to 7%

0.5 to 1%

2.5 to 4.5%

1.2%

13. Brass contains

70 - 75% copper and rest tin

90% copper and 10% tin

70% copper and 30% zinc

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

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

Acidic

Basic

Neutral

Brittle

15. Taps dies and drills contain carbon

Above 2.2%

Below 1%

Above 1%

Below 0.5%

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

By crushing into thousands of pieces

By shearing along oblique plane

By forming a bulge

In direction perpendicular to application of load

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

Elasticity

Plasticity

Malleability

Ductility

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

Refine grain structure

Reduce segregation in casting

Induce stresses

Improve mechanical properties

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

0.05 to 0.20%

0.20 to 0.45%

0.55 to 1.0%

0.45 to 0.55%

20. 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

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

Body centered cubic iron and face centered cubic iron

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

Alpha iron, beta iron and gamma iron

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

Vanadium, chromium, tungsten

Tungsten, titanium, vanadium

Tungsten, chromium, titanium

Chromium, titanium, vanadium

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

Cast steel

Brass

Cast iron

Admiralty metal

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

F.C.C. crystal structure

B.C.C. crystalline structure

A complex cubic structure

H.C.P. structure

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

Phosphor bronze

Monel metal

Silicon bronze

White metal

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

Nickel

Copper

Silicon

Chromium

27. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Nickel

Nickel and chromium

Chromium

28. Hematite iron ore contains iron about

45%

70%

55%

30%

29. Points of arrest for iron correspond to

Stages at which allotropic forms change

Stages at which properties do not change with increase in temperature

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

There is nothing like points of arrest

30. The hardness of steel primarily depends on

Shape of carbides and their distribution in iron

Percentage of alloying elements

Heat treatment employed

Percentage of carbon

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

0.35 to 0.45%

0.6 to 0.8%

0.04%

0.4 to 0.6%

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

50 : 20 : 10 : 20

50 : 20 : 20 : 10

40 : 30 : 20 : 10

30 : 20 : 30 : 20

33. Cobalt in steel

Improves wear resistance, cutting ability and toughness

Gives ductility, toughness, tensile strength and anti corrosion property

Improves cutting ability and reduce hardenability

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

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

600 VPN

250 VPN

1000 to 1100 VPN

1500 VPN

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

Surface defect

Point defect

None of these

Line defect

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

It has good machining properties

It is prone to age hardening

It is lighter than pure aluminium

It can be forged

37. 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

38. The tensile strength of wrought iron is maximum

Along the lines of slag distribution

Perpendicular to lines of slag distribution

Uniform in all directions

None of the above

39. Gamma-iron occurs between the temperature ranges of

900°C to 1400°C

600°C to 900°C

400°C to 600°C

1400°C to 1530°C

40. 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

All of the above

Have the same orientation and their similar faces are parallel

Engineering Materials Practice Set-3

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