Engineering Materials Practice Set-3

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

It can be forged

It is lighter than pure aluminium

It is prone to age hardening

It has good machining properties

2. Ductility of a material can be defined as

All of the above

Ability to recover its original form

Ability to undergo large permanent deformations in tension

Ability to undergo large permanent deformations in compression

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

Improve mechanical properties

Refine grain structure

Induce stresses

Reduce segregation in casting

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

50 : 20 : 20 : 10

30 : 20 : 30 : 20

50 : 20 : 10 : 20

40 : 30 : 20 : 10

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

White metal

Monel metal

Phosphor bronze

Silicon bronze

6. The tensile strength of wrought iron is maximum

Along the lines of slag distribution

Uniform in all directions

Perpendicular to lines of slag distribution

None of the above

7. The machinability of steel is improved by adding

Nickel and chromium

Nickel

Sulphur, lead and phosphorus

Chromium

8. 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

9. Taps dies and drills contain carbon

Above 1%

Below 0.5%

Below 1%

Above 2.2%

10. Corundum contains more than 95%

MgO

SiO₂

Al₂O₃

Steel

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11. Points of arrest for iron correspond to

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

Stages at which properties do not change with increase in temperature

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

By crushing into thousands of pieces

By forming a bulge

In direction perpendicular to application of load

By shearing along oblique plane

13. 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

14. Hematite iron ore contains iron about

70%

55%

45%

30%

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

0.45 to 0.55%

0.05 to 0.20%

0.20 to 0.45%

0.55 to 1.0%

16. Cementite consist of

6.67% carbon and 93.33% iron

13% ferrite and 87% cementite

13% cementite and 87% ferrite

13% carbon and 87% ferrite

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

Hindalium

Magnalium

Y-alloy

Duralumin

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

Admiralty metal

Brass

Cast iron

Cast steel

19. There are fourteen atoms in a unit cell of

Close packed hexagonal space lattice

None of these

Body centered cubic space lattice

Face centered cubic space lattice

20. The coke in the charge of blast furnace

Forms a slag by combining with impurities

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

Controls the grade of pig iron

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

0.4 to 0.6%

0.6 to 0.8%

0.35 to 0.45%

0.04%

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

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

Body centered cubic iron and face centered cubic iron

Alpha iron, beta iron and gamma iron

23. Brass contains

90% copper and 10% tin

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

70% copper and 30% zinc

70 - 75% copper and rest tin

24. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin, lead and silver

Tin and lead

Tin and copper

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

Plasticity

Ductility

Malleability

Elasticity

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

Hearth

Stack

Throat

Bosh

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

Vanadium, chromium, tungsten

Tungsten, chromium, titanium

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

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

Stiffness

Strength

Toughness

Brittleness

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

5 to 7%

1.2%

0.5 to 1%

2.5 to 4.5%

30. The hardness of steel primarily depends on

Percentage of carbon

Heat treatment employed

Shape of carbides and their distribution in iron

Percentage of alloying elements

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

A complex cubic structure

H.C.P. structure

B.C.C. crystalline structure

F.C.C. crystal structure

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

Ductility

Plasticity

Brittleness

Malleability

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

1000 to 1100 VPN

250 VPN

1500 VPN

600 VPN

34. The unit cells

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

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

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

Machinability

Hardenability

Weldability

Formability

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

Neutral

Acidic

Basic

Brittle

37. Gamma-iron occurs between the temperature ranges of

600°C to 900°C

400°C to 600°C

900°C to 1400°C

1400°C to 1530°C

38. Tungsten in steel

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

Improves cutting ability and reduces hardenability

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

Improves wear resistance, cutting ability and toughness

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

Brittleness

Stiffness

Strength

Toughness

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

Copper

Chromium

Silicon

Nickel

Engineering Materials Practice Set-3

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