Engineering Materials Practice Set-3

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

Silicon bronze

Phosphor bronze

White metal

Monel metal

2. 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

3. Hematite iron ore contains iron about

30%

70%

45%

55%

4. The tensile strength of wrought iron is maximum

None of the above

Uniform in all directions

Perpendicular to lines of slag distribution

Along the lines of slag distribution

5. The hardness of steel primarily depends on

Heat treatment employed

Percentage of carbon

Percentage of alloying elements

Shape of carbides and their distribution in iron

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

Brittleness

Ductility

Plasticity

Malleability

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

Basic

Brittle

Neutral

Acidic

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

Admiralty metal

Cast iron

Brass

Cast steel

9. The unit cells

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

All of the above

10. The machinability of steel is improved by adding

Nickel and chromium

Chromium

Nickel

Sulphur, lead and phosphorus

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11. Brass contains

70% copper and 30% zinc

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

70 - 75% copper and rest tin

90% copper and 10% tin

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

Alpha iron, gamma iron and delta iron

Body centered cubic iron and face centered cubic iron

Alpha iron, beta iron and gamma iron

Alpha iron and beta iron

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

Brittleness

Toughness

Strength

Stiffness

14. Taps dies and drills contain carbon

Below 1%

Above 1%

Below 0.5%

Above 2.2%

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

Brittleness

Stiffness

Strength

Toughness

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

Line defect

None of these

Surface defect

Point defect

17. The coke in the charge of blast furnace

Supplies heat to reduce ore and melt the iron

Acts as an iron bearing mineral

Forms a slag by combining with impurities

Controls the grade of pig iron

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

Formability

Machinability

Weldability

Hardenability

19. Points of arrest for iron correspond to

Stages at which allotropic forms change

Stages at which properties do not change with increase in temperature

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

There is nothing like points of arrest

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

Elasticity

Plasticity

Ductility

Malleability

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

Duralumin

Y-alloy

Hindalium

Magnalium

22. 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

23. 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

24. There are fourteen atoms in a unit cell of

None of these

Body centered cubic space lattice

Close packed hexagonal space lattice

Face centered cubic space lattice

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

40 : 30 : 20 : 10

50 : 20 : 20 : 10

50 : 20 : 10 : 20

30 : 20 : 30 : 20

26. Tungsten in steel

Improves wear resistance, cutting ability and toughness

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

27. Gamma-iron occurs between the temperature ranges of

400°C to 600°C

1400°C to 1530°C

600°C to 900°C

900°C to 1400°C

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

0.55 to 1.0%

0.45 to 0.55%

0.20 to 0.45%

0.05 to 0.20%

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

Throat

Bosh

Stack

Hearth

30. Corundum contains more than 95%

Steel

SiO₂

Al₂O₃

MgO

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

By crushing into thousands of pieces

In direction perpendicular to application of load

By shearing along oblique plane

By forming a bulge

32. Cementite consist of

13% cementite and 87% ferrite

13% ferrite and 87% cementite

6.67% carbon and 93.33% iron

13% carbon and 87% ferrite

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

Induce stresses

Improve mechanical properties

Reduce segregation in casting

Refine grain structure

34. 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%

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

1500 VPN

600 VPN

1000 to 1100 VPN

250 VPN

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

Copper

Chromium

Nickel

Silicon

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

0.35 to 0.45%

0.6 to 0.8%

0.04%

0.4 to 0.6%

38. 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

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

It has good machining properties

It is lighter than pure aluminium

It can be forged

It is prone to age hardening

40. 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

Engineering Materials Practice Set-3

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