Engineering Materials Practice Set-3

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1. Cobalt in steel

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

Improves wear resistance, cutting ability and toughness

Improves cutting ability and reduce hardenability

2. The coke in the charge of blast furnace

Supplies heat to reduce ore and melt the iron

Forms a slag by combining with impurities

Controls the grade of pig iron

Acts as an iron bearing mineral

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

It can be forged

It is prone to age hardening

It is lighter than pure aluminium

It has good machining properties

4. The tensile strength of wrought iron is maximum

None of the above

Along the lines of slag distribution

Uniform in all directions

Perpendicular to lines of slag distribution

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

Plasticity

Malleability

Ductility

Elasticity

7. Taps dies and drills contain carbon

Above 2.2%

Below 1%

Below 0.5%

Above 1%

8. Hematite iron ore contains iron about

30%

55%

70%

45%

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

0.55 to 1.0%

0.45 to 0.55%

0.20 to 0.45%

0.05 to 0.20%

10. There are fourteen atoms in a unit cell of

Face centered cubic space lattice

Close packed hexagonal space lattice

None of these

Body centered cubic space lattice

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11. 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

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

Ductility

Plasticity

Malleability

Brittleness

13. The unit cells

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

Have the same orientation and their similar faces are parallel

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

Silicon

Nickel

Copper

Chromium

15. Corundum contains more than 95%

MgO

Steel

Al₂O₃

SiO₂

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

None of these

Line defect

Point defect

Surface defect

17. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin and copper

Tin and lead

Tin, lead and silver

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

Admiralty metal

Cast steel

Cast iron

Brass

19. Gamma-iron occurs between the temperature ranges of

600°C to 900°C

900°C to 1400°C

400°C to 600°C

1400°C to 1530°C

20. Brass contains

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

70 - 75% copper and rest tin

70% copper and 30% zinc

90% copper and 10% tin

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

Acidic

Brittle

Basic

Neutral

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

Stiffness

Brittleness

Toughness

Strength

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

Stiffness

Strength

Brittleness

Toughness

24. Cementite consist of

13% carbon and 87% ferrite

13% ferrite and 87% cementite

6.67% carbon and 93.33% iron

13% cementite and 87% ferrite

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

5 to 7%

2.5 to 4.5%

0.5 to 1%

1.2%

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

Weldability

Hardenability

Formability

Machinability

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

0.6 to 0.8%

0.04%

0.4 to 0.6%

0.35 to 0.45%

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

Chromium, titanium, vanadium

Vanadium, chromium, tungsten

Tungsten, titanium, vanadium

Tungsten, chromium, titanium

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

Duralumin

Magnalium

Hindalium

Y-alloy

30. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Nickel and chromium

Chromium

Nickel

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

Refine grain structure

Induce stresses

Reduce segregation in casting

Improve mechanical properties

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

250 VPN

1000 to 1100 VPN

600 VPN

1500 VPN

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

F.C.C. crystal structure

H.C.P. structure

A complex cubic structure

B.C.C. crystalline structure

34. Ductility of a material can be defined as

Ability to undergo large permanent deformations in compression

All of the above

Ability to recover its original form

Ability to undergo large permanent deformations in tension

35. Points of arrest for iron correspond to

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

Stages at which properties do not change with increase in temperature

Stages at which allotropic forms change

There is nothing like points of arrest

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

Silicon bronze

White metal

Phosphor bronze

Monel metal

37. Tungsten in steel

Improves cutting ability and reduces hardenability

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

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

Improves wear resistance, cutting ability and toughness

38. The hardness of steel primarily depends on

Shape of carbides and their distribution in iron

Percentage of alloying elements

Percentage of carbon

Heat treatment employed

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

Stack

Hearth

Bosh

Throat

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

Alpha iron, beta iron and gamma iron

Alpha iron, gamma iron and delta iron

Body centered cubic iron and face centered cubic iron

Alpha iron and beta iron

Engineering Materials Practice Set-3

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