Engineering Materials Practice Set-3

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1. Taps dies and drills contain carbon

Below 1%

Above 1%

Below 0.5%

Above 2.2%

2. Gamma-iron occurs between the temperature ranges of

400°C to 600°C

900°C to 1400°C

600°C to 900°C

1400°C to 1530°C

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

Cast steel

Brass

Cast iron

Admiralty metal

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

Stiffness

Brittleness

Strength

Toughness

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

1500 VPN

600 VPN

1000 to 1100 VPN

250 VPN

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, gamma iron and delta iron

Alpha iron, beta iron and gamma iron

7. 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

8. There are fourteen atoms in a unit cell of

Face centered cubic space lattice

Close packed hexagonal space lattice

None of these

Body centered cubic space lattice

9. 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

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

Chromium, titanium, vanadium

Vanadium, chromium, tungsten

Tungsten, chromium, titanium

Tungsten, titanium, vanadium

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

Copper

Nickel

Chromium

Silicon

12. The coke in the charge of blast furnace

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

Controls the grade of pig iron

Forms a slag by combining with impurities

13. The tensile strength of wrought iron is maximum

Perpendicular to lines of slag distribution

Uniform in all directions

Along the lines of slag distribution

None of the above

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

Malleability

Ductility

Brittleness

Plasticity

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

Hindalium

Magnalium

Duralumin

Y-alloy

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

Weldability

Hardenability

Machinability

Formability

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

Brittle

Neutral

Acidic

Basic

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

Improve mechanical properties

Refine grain structure

Induce stresses

Reduce segregation in casting

19. Tungsten in steel

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

Improves cutting ability and reduces hardenability

Improves wear resistance, cutting ability and toughness

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

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

Point defect

None of these

Surface defect

Line defect

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

5 to 7%

0.5 to 1%

2.5 to 4.5%

1.2%

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

Throat

Bosh

Hearth

Stack

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

By crushing into thousands of pieces

By shearing along oblique plane

In direction perpendicular to application of load

By forming a bulge

24. 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

25. Points of arrest for iron correspond to

There is nothing like points of arrest

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

26. Corundum contains more than 95%

Steel

SiO₂

MgO

Al₂O₃

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

B.C.C. crystalline structure

A complex cubic structure

H.C.P. structure

F.C.C. crystal structure

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

Monel metal

White metal

Silicon bronze

Phosphor bronze

29. Hematite iron ore contains iron about

55%

70%

45%

30%

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

0.45 to 0.55%

0.05 to 0.20%

0.55 to 1.0%

0.20 to 0.45%

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31. 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

32. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin, lead and silver

Tin and lead

Tin and copper

33. The hardness of steel primarily depends on

Shape of carbides and their distribution in iron

Percentage of carbon

Percentage of alloying elements

Heat treatment employed

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

30 : 20 : 30 : 20

50 : 20 : 10 : 20

50 : 20 : 20 : 10

40 : 30 : 20 : 10

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

Elasticity

Plasticity

Malleability

Ductility

36. Brass contains

90% copper and 10% tin

70% copper and 30% zinc

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

70 - 75% copper and rest tin

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

Toughness

Brittleness

Stiffness

Strength

38. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Nickel and chromium

Nickel

Chromium

39. 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%

0.35 to 0.45%

0.4 to 0.6%

40. 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

Engineering Materials Practice Set-3

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