Engineering Materials Practice Set-3

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1. Brass contains

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

70% copper and 30% zinc

90% copper and 10% tin

70 - 75% copper and rest tin

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

Neutral

Acidic

Basic

Brittle

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

50 : 20 : 10 : 20

30 : 20 : 30 : 20

50 : 20 : 20 : 10

40 : 30 : 20 : 10

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

250 VPN

1000 to 1100 VPN

1500 VPN

600 VPN

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

Magnalium

Duralumin

Hindalium

Y-alloy

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

Monel metal

Silicon bronze

White metal

Phosphor bronze

7. Corundum contains more than 95%

Al₂O₃

Steel

MgO

SiO₂

8. 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

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

Line defect

Surface defect

None of these

Point defect

10. The tensile strength of wrought iron is maximum

Uniform in all directions

None of the above

Along the lines of slag distribution

Perpendicular to lines of slag distribution

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

Vanadium, chromium, tungsten

Tungsten, titanium, vanadium

Chromium, titanium, vanadium

Tungsten, chromium, titanium

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

Formability

Weldability

Hardenability

Machinability

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

0.5 to 1%

5 to 7%

2.5 to 4.5%

1.2%

14. Tungsten in steel

Improves cutting ability and reduces hardenability

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

Improves wear resistance, cutting ability and toughness

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

15. 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

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

Alpha iron, beta iron and gamma iron

Alpha iron, gamma iron and delta iron

Alpha iron and beta iron

Body centered cubic iron and face centered cubic iron

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

By shearing along oblique plane

By forming a bulge

By crushing into thousands of pieces

In direction perpendicular to application of load

18. 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%

0.04%

0.35 to 0.45%

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

Toughness

Stiffness

Strength

Brittleness

20. 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

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21. Taps dies and drills contain carbon

Above 2.2%

Below 0.5%

Below 1%

Above 1%

22. Hematite iron ore contains iron about

45%

55%

70%

30%

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

Plasticity

Ductility

Malleability

Elasticity

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

Reduce segregation in casting

Improve mechanical properties

Induce stresses

Refine grain structure

25. Gamma-iron occurs between the temperature ranges of

900°C to 1400°C

600°C to 900°C

400°C to 600°C

1400°C to 1530°C

26. 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 compression

Ability to undergo large permanent deformations in tension

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

Plasticity

Malleability

Brittleness

Ductility

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

B.C.C. crystalline structure

F.C.C. crystal structure

A complex cubic structure

H.C.P. structure

29. The unit cells

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

May be defined as the smallest parallelepiped which could be transposed in three coordinate directions to build up the space lattice

30. The usual composition of a soldering alloy is

Tin and copper

Tin and lead

Tin, lead and small percentage of antimony

Tin, lead and silver

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31. The hardness of steel primarily depends on

Percentage of alloying elements

Shape of carbides and their distribution in iron

Heat treatment employed

Percentage of carbon

32. There are fourteen atoms in a unit cell of

Body centered cubic space lattice

None of these

Close packed hexagonal space lattice

Face centered cubic space lattice

33. The machinability of steel is improved by adding

Chromium

Sulphur, lead and phosphorus

Nickel

Nickel and chromium

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

Throat

Stack

Hearth

Bosh

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

Brittleness

Stiffness

Toughness

Strength

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

Silicon

Chromium

Nickel

Copper

37. 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

38. Cementite consist of

13% ferrite and 87% cementite

6.67% carbon and 93.33% iron

13% cementite and 87% ferrite

13% carbon and 87% ferrite

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

Admiralty metal

Brass

Cast iron

Cast steel

40. 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%

Engineering Materials Practice Set-3

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