Engineering Materials Practice Set-3

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1. Hematite iron ore contains iron about

45%

55%

70%

30%

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

In direction perpendicular to application of load

By crushing into thousands of pieces

By forming a bulge

By shearing along oblique plane

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

Basic

Acidic

Brittle

Neutral

4. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin and lead

Tin, lead and silver

Tin and copper

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

2.5 to 4.5%

5 to 7%

0.5 to 1%

1.2%

6. 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

7. The hardness of steel primarily depends on

Percentage of alloying elements

Heat treatment employed

Shape of carbides and their distribution in iron

Percentage of carbon

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

Machinability

Weldability

Formability

Hardenability

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

Monel metal

Phosphor bronze

Silicon bronze

White metal

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

0.55 to 1.0%

0.05 to 0.20%

0.20 to 0.45%

0.45 to 0.55%

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

Admiralty metal

Brass

Cast iron

Cast steel

12. Cementite consist of

6.67% carbon and 93.33% iron

13% carbon and 87% ferrite

13% ferrite and 87% cementite

13% cementite and 87% ferrite

13. Brass contains

70% copper and 30% zinc

90% copper and 10% tin

70 - 75% copper and rest tin

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

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

Toughness

Strength

Brittleness

Stiffness

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

Silicon

Nickel

Copper

Chromium

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

Tungsten, chromium, titanium

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

Vanadium, chromium, tungsten

17. 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

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

Refine grain structure

Induce stresses

Improve mechanical properties

Reduce segregation in casting

19. Gamma-iron occurs between the temperature ranges of

600°C to 900°C

1400°C to 1530°C

400°C to 600°C

900°C to 1400°C

20. The coke in the charge of blast furnace

Controls the grade of pig iron

Acts as an iron bearing mineral

Forms a slag by combining with impurities

Supplies heat to reduce ore and melt the iron

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21. Corundum contains more than 95%

Steel

SiO₂

Al₂O₃

MgO

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

Alpha iron, gamma iron and delta iron

Alpha iron and beta iron

Alpha iron, beta iron and gamma iron

Body centered cubic iron and face centered cubic iron

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

Magnalium

Y-alloy

Duralumin

Hindalium

24. There are fourteen atoms in a unit cell of

Close packed hexagonal space lattice

Face centered cubic space lattice

None of these

Body centered cubic space lattice

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

Malleability

Plasticity

Brittleness

Ductility

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

Toughness

Stiffness

Brittleness

Strength

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

50 : 20 : 20 : 10

40 : 30 : 20 : 10

50 : 20 : 10 : 20

30 : 20 : 30 : 20

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

Surface defect

Point defect

Line defect

None of these

29. 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

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

It can be forged

It is lighter than pure aluminium

It has good machining properties

It is prone to age hardening

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31. Cobalt in steel

Improves cutting ability and reduce hardenability

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

Improves wear resistance, cutting ability and toughness

Gives ductility, toughness, tensile strength and anti corrosion property

32. Taps dies and drills contain carbon

Below 1%

Above 1%

Above 2.2%

Below 0.5%

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

Stack

Bosh

Hearth

Throat

34. The tensile strength of wrought iron is maximum

Perpendicular to lines of slag distribution

Uniform in all directions

None of the above

Along the lines of slag distribution

35. The unit cells

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

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

36. The machinability of steel is improved by adding

Chromium

Sulphur, lead and phosphorus

Nickel and chromium

Nickel

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

0.04%

0.6 to 0.8%

0.35 to 0.45%

0.4 to 0.6%

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

600 VPN

250 VPN

1500 VPN

1000 to 1100 VPN

39. 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

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

Ductility

Malleability

Plasticity

Elasticity

Engineering Materials Practice Set-3

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