Engineering Materials Practice Set-3

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

Vanadium, chromium, tungsten

Tungsten, chromium, titanium

Tungsten, titanium, vanadium

Chromium, titanium, vanadium

2. Cementite consist of

13% ferrite and 87% cementite

13% cementite and 87% ferrite

13% carbon and 87% ferrite

6.67% carbon and 93.33% iron

3. Corundum contains more than 95%

Al₂O₃

Steel

MgO

SiO₂

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

Phosphor bronze

White metal

Silicon bronze

Monel metal

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

0.45 to 0.55%

0.55 to 1.0%

0.05 to 0.20%

0.20 to 0.45%

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

0.04%

0.6 to 0.8%

0.35 to 0.45%

0.4 to 0.6%

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

Alpha iron and beta iron

Alpha iron, beta iron and gamma iron

Body centered cubic iron and face centered cubic iron

Alpha iron, gamma iron and delta iron

8. There are fourteen atoms in a unit cell of

Close packed hexagonal space lattice

Face centered cubic space lattice

Body centered cubic space lattice

None of these

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

Malleability

Elasticity

Plasticity

Ductility

10. Taps dies and drills contain carbon

Below 1%

Below 0.5%

Above 2.2%

Above 1%

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11. The tensile strength of wrought iron is maximum

Along the lines of slag distribution

None of the above

Perpendicular to lines of slag distribution

Uniform in all directions

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

Duralumin

Hindalium

Magnalium

Y-alloy

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

Stack

Hearth

Bosh

Throat

14. Tungsten in steel

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

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

15. The coke in the charge of blast furnace

Controls the grade of pig iron

Supplies heat to reduce ore and melt the iron

Forms a slag by combining with impurities

Acts as an iron bearing mineral

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

It is prone to age hardening

It is lighter than pure aluminium

It has good machining properties

It can be forged

17. Brass contains

90% copper and 10% tin

70 - 75% copper and rest tin

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

70% copper and 30% zinc

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

Plasticity

Brittleness

Ductility

Malleability

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

Basic

Brittle

Neutral

Acidic

20. The unit cells

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

All of the above

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

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

Strength

Brittleness

Toughness

Stiffness

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

Silicon

Nickel

Chromium

Copper

23. The hardness of steel primarily depends on

Shape of carbides and their distribution in iron

Percentage of carbon

Heat treatment employed

Percentage of alloying elements

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

In direction perpendicular to application of load

By forming a bulge

By crushing into thousands of pieces

By shearing along oblique plane

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

Hardenability

Machinability

Formability

Weldability

26. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin and lead

Tin and copper

Tin, lead and silver

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

Admiralty metal

Cast steel

Brass

Cast iron

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

None of these

Surface defect

Line defect

Point defect

29. Cobalt in steel

Gives ductility, toughness, tensile strength and anti corrosion property

Improves wear resistance, cutting ability and toughness

Improves cutting ability and reduce hardenability

Refines grain size and produces less tendency to carburisation, improve corrosion and heat resistant proper ties

30. The machinability of steel is improved by adding

Chromium

Nickel and chromium

Sulphur, lead and phosphorus

Nickel

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31. 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

32. Ductility of a material can be defined as

All of the above

Ability to undergo large permanent deformations in compression

Ability to recover its original form

Ability to undergo large permanent deformations in tension

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

Brittleness

Strength

Stiffness

Toughness

34. Points of arrest for iron correspond to

There is nothing like points of arrest

Stages at which properties do not change with increase in temperature

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

Stages at which allotropic forms change

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

1500 VPN

250 VPN

600 VPN

1000 to 1100 VPN

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

A complex cubic structure

F.C.C. crystal structure

B.C.C. crystalline structure

H.C.P. structure

37. Gamma-iron occurs between the temperature ranges of

1400°C to 1530°C

900°C to 1400°C

600°C to 900°C

400°C to 600°C

38. Hematite iron ore contains iron about

70%

45%

55%

30%

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

Reduce segregation in casting

Induce stresses

Improve mechanical properties

Refine grain structure

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

2.5 to 4.5%

0.5 to 1%

1.2%

5 to 7%

Engineering Materials Practice Set-3

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