Engineering Materials Practice Set-3

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1. Gamma-iron occurs between the temperature ranges of

1400°C to 1530°C

400°C to 600°C

600°C to 900°C

900°C to 1400°C

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

Nickel

Silicon

Copper

Chromium

3. Cobalt in steel

Improves cutting ability and reduce hardenability

Gives ductility, toughness, tensile strength and anti corrosion property

Improves wear resistance, cutting ability and toughness

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

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

Malleability

Ductility

Plasticity

Brittleness

5. Points of arrest for iron correspond to

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

There is nothing like points of arrest

6. The unit cells

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

Have the same orientation and their similar faces are parallel

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

0.55 to 1.0%

0.45 to 0.55%

0.05 to 0.20%

0.20 to 0.45%

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

It has good machining properties

It can be forged

It is lighter than pure aluminium

It is prone to age hardening

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

Formability

Hardenability

Weldability

Machinability

10. The machinability of steel is improved by adding

Sulphur, lead and phosphorus

Nickel and chromium

Chromium

Nickel

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

Body centered cubic iron and face centered cubic iron

Alpha iron, beta iron and gamma iron

Alpha iron and beta iron

Alpha iron, gamma iron and delta iron

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

Silicon bronze

Monel metal

White metal

Phosphor bronze

13. The usual composition of a soldering alloy is

Tin, lead and small percentage of antimony

Tin and copper

Tin and lead

Tin, lead and silver

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

Vanadium, chromium, tungsten

Tungsten, titanium, vanadium

Tungsten, chromium, titanium

Chromium, titanium, vanadium

15. Hematite iron ore contains iron about

70%

45%

55%

30%

16. The coke in the charge of blast furnace

Controls the grade of pig iron

Acts as an iron bearing mineral

Forms a slag by combining with impurities

Supplies heat to reduce ore and melt the iron

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

1000 to 1100 VPN

1500 VPN

600 VPN

250 VPN

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

Stiffness

Toughness

Strength

Brittleness

19. Cementite consist of

13% carbon and 87% ferrite

13% ferrite and 87% cementite

6.67% carbon and 93.33% iron

13% cementite and 87% ferrite

20. The tensile strength of wrought iron is maximum

Uniform in all directions

Perpendicular to lines of slag distribution

None of the above

Along the lines of slag distribution

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21. Ductility of a material can be defined as

Ability to recover its original form

All of the above

Ability to undergo large permanent deformations in compression

Ability to undergo large permanent deformations in tension

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

Throat

Hearth

Stack

Bosh

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

F.C.C. crystal structure

B.C.C. crystalline structure

H.C.P. structure

A complex cubic structure

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

Cast steel

Cast iron

Admiralty metal

Brass

25. Taps dies and drills contain carbon

Above 2.2%

Above 1%

Below 1%

Below 0.5%

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

Strength

Brittleness

Stiffness

Toughness

27. Brass contains

70% copper and 30% zinc

90% copper and 10% tin

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

70 - 75% copper and rest tin

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

0.04%

0.4 to 0.6%

0.35 to 0.45%

0.6 to 0.8%

29. The hardness of steel primarily depends on

Heat treatment employed

Percentage of alloying elements

Percentage of carbon

Shape of carbides and their distribution in iron

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

Neutral

Acidic

Basic

Brittle

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

Refine grain structure

Improve mechanical properties

Reduce segregation in casting

Induce stresses

32. There are fourteen atoms in a unit cell of

Face centered cubic space lattice

None of these

Body centered cubic space lattice

Close packed hexagonal space lattice

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

Point defect

Surface defect

Line defect

None of these

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

5 to 7%

2.5 to 4.5%

1.2%

0.5 to 1%

35. Tungsten in steel

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

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

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

By forming a bulge

By shearing along oblique plane

In direction perpendicular to application of load

By crushing into thousands of pieces

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

Y-alloy

Duralumin

Magnalium

Hindalium

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

50 : 20 : 20 : 10

30 : 20 : 30 : 20

40 : 30 : 20 : 10

50 : 20 : 10 : 20

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

Plasticity

Ductility

Malleability

Elasticity

40. Corundum contains more than 95%

Al₂O₃

Steel

SiO₂

MgO

Engineering Materials Practice Set-3

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