Engineering Materials Practice Set-3

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

Brittleness

Stiffness

Strength

Toughness

2. The hardness of steel primarily depends on

Shape of carbides and their distribution in iron

Heat treatment employed

Percentage of alloying elements

Percentage of carbon

3. Brass contains

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

90% copper and 10% tin

70 - 75% copper and rest tin

70% copper and 30% zinc

4. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Chromium

Nickel

Nickel and chromium

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

30 : 20 : 30 : 20

50 : 20 : 20 : 10

50 : 20 : 10 : 20

40 : 30 : 20 : 10

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

Basic

Brittle

Acidic

Neutral

7. The tensile strength of wrought iron is maximum

None of the above

Uniform in all directions

Along the lines of slag distribution

Perpendicular to lines of slag distribution

8. Taps dies and drills contain carbon

Above 1%

Above 2.2%

Below 1%

Below 0.5%

9. Cementite consist of

13% carbon and 87% ferrite

6.67% carbon and 93.33% iron

13% ferrite and 87% cementite

13% cementite and 87% ferrite

10. 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 further heating does not increase temperature for some time

Stages at which allotropic forms change

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11. Ductility of a material can be defined as

Ability to recover its original form

Ability to undergo large permanent deformations in compression

All of the above

Ability to undergo large permanent deformations in tension

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

Point defect

Line defect

Surface defect

None of these

13. The unit cells

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

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

Have the same orientation and their similar faces are parallel

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

0.20 to 0.45%

0.45 to 0.55%

0.55 to 1.0%

0.05 to 0.20%

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

Phosphor bronze

White metal

Silicon bronze

Monel metal

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

Cast iron

Admiralty metal

Brass

Cast steel

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

Induce stresses

Improve mechanical properties

Reduce segregation in casting

Refine grain structure

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

Throat

Bosh

Hearth

Stack

19. The usual composition of a soldering alloy is

Tin and copper

Tin, lead and silver

Tin and lead

Tin, lead and small percentage of antimony

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

Ductility

Brittleness

Malleability

Plasticity

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21. 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%

0.6 to 0.8%

0.35 to 0.45%

22. Hematite iron ore contains iron about

45%

70%

55%

30%

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

Elasticity

Malleability

Plasticity

Ductility

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

It is lighter than pure aluminium

It is prone to age hardening

It can be forged

It has good machining properties

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

Tungsten, chromium, titanium

Vanadium, chromium, tungsten

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

26. Tungsten in steel

Improves cutting ability and reduces hardenability

Improves wear resistance, cutting ability and toughness

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

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

27. The coke in the charge of blast furnace

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

Controls the grade of pig iron

Forms a slag by combining with impurities

28. 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

29. Cobalt in steel

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

Improves wear resistance, cutting ability and toughness

Improves cutting ability and reduce hardenability

Gives ductility, toughness, tensile strength and anti corrosion property

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

Machinability

Hardenability

Weldability

Formability

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

Toughness

Brittleness

Strength

Stiffness

32. Corundum contains more than 95%

Steel

MgO

Al₂O₃

SiO₂

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

By forming a bulge

By crushing into thousands of pieces

In direction perpendicular to application of load

By shearing along oblique plane

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

600 VPN

1000 to 1100 VPN

1500 VPN

250 VPN

35. 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%

36. There are fourteen atoms in a unit cell of

None of these

Close packed hexagonal space lattice

Face centered cubic space lattice

Body centered cubic space lattice

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

Hindalium

Y-alloy

Duralumin

Magnalium

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

Alpha iron, beta iron and gamma iron

Body centered cubic iron and face centered cubic iron

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

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

Silicon

Nickel

Copper

Chromium

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

H.C.P. structure

A complex cubic structure

B.C.C. crystalline structure

F.C.C. crystal structure

Engineering Materials Practice Set-3

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