Engineering Materials Practice Set-3

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1. Tungsten in steel

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 wear resistance, cutting ability and toughness

Improves cutting ability and reduces hardenability

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

By shearing along oblique plane

By crushing into thousands of pieces

In direction perpendicular to application of load

By forming a bulge

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

1500 VPN

600 VPN

250 VPN

1000 to 1100 VPN

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

1.2%

0.5 to 1%

5 to 7%

2.5 to 4.5%

5. There are fourteen atoms in a unit cell of

Face centered cubic space lattice

Close packed hexagonal space lattice

Body centered cubic space lattice

None of these

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

Brittleness

Ductility

Malleability

Plasticity

7. Corundum contains more than 95%

SiO₂

MgO

Steel

Al₂O₃

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

Admiralty metal

Cast steel

Brass

Cast iron

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

30 : 20 : 30 : 20

40 : 30 : 20 : 10

50 : 20 : 20 : 10

50 : 20 : 10 : 20

10. The coke in the charge of blast furnace

Controls the grade of pig iron

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

Forms a slag by combining with impurities

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11. The tensile strength of wrought iron is maximum

Uniform in all directions

Along the lines of slag distribution

None of the above

Perpendicular to lines of slag distribution

12. 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

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

Magnalium

Duralumin

Hindalium

Y-alloy

14. 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 allotropic forms change

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

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

Bosh

Throat

Hearth

Stack

16. 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%

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

Machinability

Weldability

Hardenability

Formability

18. The unit cells

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

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

All of the above

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

Toughness

Brittleness

Stiffness

Strength

20. 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

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21. Gamma-iron occurs between the temperature ranges of

1400°C to 1530°C

400°C to 600°C

900°C to 1400°C

600°C to 900°C

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

Stiffness

Toughness

Brittleness

Strength

23. Taps dies and drills contain carbon

Above 2.2%

Below 1%

Below 0.5%

Above 1%

24. 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

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

White metal

Silicon bronze

Monel metal

Phosphor bronze

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

Nickel

Chromium

Silicon

Copper

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

It is lighter than pure aluminium

It can be forged

It has good machining properties

It is prone to age hardening

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

Surface defect

None of these

Line defect

Point defect

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

Malleability

Ductility

Plasticity

Elasticity

30. 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

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31. 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

32. The usual composition of a soldering alloy is

Tin and copper

Tin, lead and silver

Tin, lead and small percentage of antimony

Tin and lead

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

Body centered cubic iron and face centered cubic iron

Alpha iron, gamma iron and delta iron

Alpha iron and beta iron

Alpha iron, beta iron and gamma iron

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

Vanadium, chromium, tungsten

Chromium, titanium, vanadium

Tungsten, chromium, titanium

Tungsten, titanium, vanadium

35. The machinability of steel is improved by adding

Nickel

Nickel and chromium

Chromium

Sulphur, lead and phosphorus

36. Cementite consist of

6.67% carbon and 93.33% iron

13% ferrite and 87% cementite

13% carbon and 87% ferrite

13% cementite and 87% ferrite

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

Induce stresses

Improve mechanical properties

Reduce segregation in casting

Refine grain structure

38. 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%

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

Acidic

Basic

Neutral

Brittle

40. Hematite iron ore contains iron about

30%

45%

55%

70%

Engineering Materials Practice Set-3

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