Engineering Materials Practice Set-3

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

1500 VPN

1000 to 1100 VPN

250 VPN

600 VPN

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

Y-alloy

Hindalium

Magnalium

Duralumin

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

0.45 to 0.55%

0.20 to 0.45%

0.05 to 0.20%

0.55 to 1.0%

4. The coke in the charge of blast furnace

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

Forms a slag by combining with impurities

Controls the grade of pig iron

5. 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

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

Body centered cubic iron and face centered cubic iron

Alpha iron and beta iron

Alpha iron, beta iron and gamma iron

Alpha iron, gamma iron and delta iron

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

5 to 7%

1.2%

2.5 to 4.5%

0.5 to 1%

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

Basic

Neutral

Brittle

Acidic

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

Formability

Machinability

Hardenability

Weldability

10. Brass contains

90% copper and 10% tin

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

70 - 75% copper and rest tin

70% copper and 30% zinc

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11. Corundum contains more than 95%

MgO

SiO₂

Al₂O₃

Steel

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

Copper

Nickel

Silicon

Chromium

13. 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

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

Monel metal

Phosphor bronze

White metal

Silicon bronze

15. Cementite consist of

13% carbon and 87% ferrite

13% ferrite and 87% cementite

13% cementite and 87% ferrite

6.67% carbon and 93.33% iron

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

Toughness

Brittleness

Stiffness

Strength

17. There are fourteen atoms in a unit cell of

None of these

Face centered cubic space lattice

Body centered cubic space lattice

Close packed hexagonal space lattice

18. Cobalt in steel

Improves cutting ability and reduce hardenability

Improves wear resistance, cutting ability and toughness

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

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

Stiffness

Brittleness

Strength

Toughness

20. Tungsten in steel

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

Improves cutting ability and reduces hardenability

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21. The usual composition of a soldering alloy is

Tin, lead and silver

Tin and lead

Tin, lead and small percentage of antimony

Tin and copper

22. 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%

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

A complex cubic structure

F.C.C. crystal structure

H.C.P. structure

B.C.C. crystalline structure

24. Points of arrest for iron correspond to

Stages at which allotropic forms change

There is nothing like points of arrest

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

Stages at which properties do not change with increase in temperature

25. Hematite iron ore contains iron about

70%

30%

55%

45%

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

40 : 30 : 20 : 10

50 : 20 : 10 : 20

50 : 20 : 20 : 10

30 : 20 : 30 : 20

27. 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

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

Plasticity

Malleability

Ductility

Brittleness

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

By forming a bulge

By crushing into thousands of pieces

By shearing along oblique plane

In direction perpendicular to application of load

30. The tensile strength of wrought iron is maximum

Perpendicular to lines of slag distribution

None of the above

Uniform in all directions

Along the lines of slag distribution

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

Bosh

Hearth

Throat

Stack

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

None of these

Point defect

Line defect

Surface defect

33. The unit cells

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

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

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

Brass

Cast steel

Admiralty metal

Cast iron

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

Refine grain structure

Induce stresses

Improve mechanical properties

Reduce segregation in casting

36. The machinability of steel is improved by adding

Nickel and chromium

Chromium

Nickel

Sulphur, lead and phosphorus

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

Ductility

Elasticity

Malleability

Plasticity

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

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

Vanadium, chromium, tungsten

Tungsten, chromium, titanium

39. Taps dies and drills contain carbon

Below 0.5%

Above 2.2%

Above 1%

Below 1%

40. Gamma-iron occurs between the temperature ranges of

1400°C to 1530°C

900°C to 1400°C

400°C to 600°C

600°C to 900°C

Engineering Materials Practice Set-3

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