Engineering Materials Practice Set-3

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

Y-alloy

Hindalium

Duralumin

Magnalium

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

Brittleness

Malleability

Ductility

Plasticity

3. The coke in the charge of blast furnace

Forms a slag by combining with impurities

Acts as an iron bearing mineral

Controls the grade of pig iron

Supplies heat to reduce ore and melt the iron

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

Reduce segregation in casting

Induce stresses

Improve mechanical properties

Refine grain structure

5. The usual composition of a soldering alloy is

Tin and copper

Tin, lead and small percentage of antimony

Tin and lead

Tin, lead and silver

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

Chromium

Copper

Silicon

Nickel

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

Toughness

Brittleness

Stiffness

Strength

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

0.6 to 0.8%

0.35 to 0.45%

0.04%

0.4 to 0.6%

9. Corundum contains more than 95%

Al₂O₃

SiO₂

Steel

MgO

10. Hematite iron ore contains iron about

55%

45%

30%

70%

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

By shearing along oblique plane

By forming a bulge

In direction perpendicular to application of load

By crushing into thousands of pieces

12. There are fourteen atoms in a unit cell of

Face centered cubic space lattice

Body centered cubic space lattice

Close packed hexagonal space lattice

None of these

13. Gamma-iron occurs between the temperature ranges of

1400°C to 1530°C

400°C to 600°C

900°C to 1400°C

600°C to 900°C

14. The unit cells

Have the same orientation and their similar faces are parallel

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

All of the above

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

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

Toughness

Strength

Stiffness

Brittleness

16. Cobalt in steel

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

Gives ductility, toughness, tensile strength and anti corrosion property

Improves wear resistance, cutting ability and toughness

Improves cutting ability and reduce hardenability

17. Ductility of a material can be defined as

Ability to undergo large permanent deformations in tension

All of the above

Ability to recover its original form

Ability to undergo large permanent deformations in compression

18. Cementite consist of

13% ferrite and 87% cementite

13% carbon and 87% ferrite

6.67% carbon and 93.33% iron

13% cementite and 87% ferrite

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

1.2%

2.5 to 4.5%

0.5 to 1%

5 to 7%

20. Brass contains

70% copper and 30% zinc

90% copper and 10% tin

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

70 - 75% copper and rest tin

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21. Points of arrest for iron correspond to

Stages at which allotropic forms change

Stages at which properties do not change with increase in temperature

There is nothing like points of arrest

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

22. 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, gamma iron and delta iron

Alpha iron and beta iron

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

It has good machining properties

It can be forged

It is lighter than pure aluminium

It is prone to age hardening

24. Taps dies and drills contain carbon

Above 1%

Below 1%

Below 0.5%

Above 2.2%

25. The hardness of steel primarily depends on

Heat treatment employed

Percentage of alloying elements

Shape of carbides and their distribution in iron

Percentage of carbon

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

50 : 20 : 20 : 10

50 : 20 : 10 : 20

30 : 20 : 30 : 20

40 : 30 : 20 : 10

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

Malleability

Elasticity

Ductility

Plasticity

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

Bosh

Throat

Stack

Hearth

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

Line defect

Surface defect

None of these

Point defect

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

0.05 to 0.20%

0.55 to 1.0%

0.45 to 0.55%

0.20 to 0.45%

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

White metal

Phosphor bronze

Monel metal

Silicon bronze

32. Tungsten in steel

Improves cutting ability and reduces hardenability

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

Improves wear resistance, cutting ability and toughness

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

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

A complex cubic structure

B.C.C. crystalline structure

F.C.C. crystal structure

H.C.P. structure

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

Formability

Weldability

Hardenability

Machinability

35. The machinability of steel is improved by adding

Nickel

Chromium

Sulphur, lead and phosphorus

Nickel and chromium

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

Basic

Neutral

Brittle

Acidic

37. The tensile strength of wrought iron is maximum

Uniform in all directions

Perpendicular to lines of slag distribution

None of the above

Along the lines of slag distribution

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

Cast steel

Cast iron

Brass

Admiralty metal

39. 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

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

250 VPN

600 VPN

1500 VPN

1000 to 1100 VPN

Engineering Materials Practice Set-3

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