Engineering Materials Practice Set-3

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1. Points of arrest for iron correspond to

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

Stages at which properties do not change with increase in temperature

Stages at which allotropic forms change

There is nothing like points of arrest

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

It is lighter than pure aluminium

It has good machining properties

It can be forged

It is prone to age hardening

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

F.C.C. crystal structure

A complex cubic structure

H.C.P. structure

B.C.C. crystalline structure

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

Silicon bronze

White metal

Phosphor bronze

Monel metal

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

Stiffness

Strength

Brittleness

Toughness

6. The coke in the charge of blast furnace

Controls the grade of pig iron

Forms a slag by combining with impurities

Acts as an iron bearing mineral

Supplies heat to reduce ore and melt the iron

7. 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

8. Cobalt in steel

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

Improves cutting ability and reduce hardenability

Improves wear resistance, cutting ability and toughness

Gives ductility, toughness, tensile strength and anti corrosion property

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

Duralumin

Hindalium

Magnalium

Y-alloy

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

0.55 to 1.0%

0.20 to 0.45%

0.05 to 0.20%

0.45 to 0.55%

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11. Hematite iron ore contains iron about

70%

30%

55%

45%

12. The tensile strength of wrought iron is maximum

None of the above

Perpendicular to lines of slag distribution

Uniform in all directions

Along the lines of slag distribution

13. 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

14. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin and lead

Tin, lead and silver

Tin and copper

15. Taps dies and drills contain carbon

Above 1%

Below 1%

Below 0.5%

Above 2.2%

16. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Nickel and chromium

Chromium

Nickel

17. There are fourteen atoms in a unit cell of

Body centered cubic space lattice

Close packed hexagonal space lattice

Face centered cubic space lattice

None of these

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

Plasticity

Malleability

Ductility

Brittleness

19. Corundum contains more than 95%

MgO

Steel

Al₂O₃

SiO₂

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

Admiralty metal

Cast steel

Brass

Cast iron

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

250 VPN

1500 VPN

600 VPN

1000 to 1100 VPN

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

Improve mechanical properties

Induce stresses

Reduce segregation in casting

Refine grain structure

23. 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%

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

Basic

Neutral

Brittle

Acidic

25. Brass contains

70% copper and 30% zinc

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

90% copper and 10% tin

70 - 75% copper and rest tin

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

0.4 to 0.6%

0.04%

0.6 to 0.8%

0.35 to 0.45%

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

Chromium

Copper

Silicon

Nickel

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

By forming a bulge

In direction perpendicular to application of load

By shearing along oblique plane

By crushing into thousands of pieces

29. The hardness of steel primarily depends on

Percentage of carbon

Percentage of alloying elements

Shape of carbides and their distribution in iron

Heat treatment employed

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

Tungsten, titanium, vanadium

Vanadium, chromium, tungsten

Chromium, titanium, vanadium

Tungsten, chromium, titanium

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31. 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

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

Ductility

Elasticity

Malleability

Plasticity

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

Formability

Machinability

Weldability

Hardenability

34. Ductility of a material can be defined as

All of the above

Ability to undergo large permanent deformations in tension

Ability to recover its original form

Ability to undergo large permanent deformations in compression

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

Strength

Stiffness

Brittleness

Toughness

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

50 : 20 : 10 : 20

50 : 20 : 20 : 10

30 : 20 : 30 : 20

40 : 30 : 20 : 10

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

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

Alpha iron, beta iron and gamma iron

Body centered cubic iron and face centered cubic iron

38. The unit cells

Have the same orientation and their similar faces are parallel

All of the above

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

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

Hearth

Throat

Stack

Bosh

40. Cementite consist of

13% cementite and 87% ferrite

6.67% carbon and 93.33% iron

13% ferrite and 87% cementite

13% carbon and 87% ferrite

Engineering Materials Practice Set-3

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