Engineering Materials Practice Set-3

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

Machinability

Weldability

Formability

Hardenability

2. Corundum contains more than 95%

Steel

MgO

Al₂O₃

SiO₂

3. 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

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

Alpha iron, gamma iron and delta iron

Alpha iron, beta iron and gamma iron

Alpha iron and beta iron

Body centered cubic iron and face centered cubic iron

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

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

Vanadium, chromium, tungsten

Tungsten, chromium, titanium

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

By forming a bulge

By crushing into thousands of pieces

By shearing along oblique plane

In direction perpendicular to application of load

7. Gamma-iron occurs between the temperature ranges of

600°C to 900°C

400°C to 600°C

1400°C to 1530°C

900°C to 1400°C

8. Hematite iron ore contains iron about

55%

30%

45%

70%

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

Refine grain structure

Reduce segregation in casting

Improve mechanical properties

Induce stresses

10. Cobalt in steel

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

Improves cutting ability and reduce hardenability

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

Stack

Hearth

Bosh

Throat

12. Cementite consist of

13% cementite and 87% ferrite

13% ferrite and 87% cementite

13% carbon and 87% ferrite

6.67% carbon and 93.33% iron

13. Tungsten in steel

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

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

14. 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

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

600 VPN

1000 to 1100 VPN

1500 VPN

250 VPN

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

Admiralty metal

Cast steel

Brass

Cast iron

17. The machinability of steel is improved by adding

Nickel and chromium

Chromium

Nickel

Sulphur, lead and phosphorus

18. 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

19. 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

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

Nickel

Copper

Chromium

Silicon

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

1.2%

0.5 to 1%

5 to 7%

2.5 to 4.5%

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

Strength

Stiffness

Toughness

Brittleness

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

Silicon bronze

Monel metal

Phosphor bronze

White metal

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

Hindalium

Duralumin

Magnalium

Y-alloy

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

0.05 to 0.20%

0.20 to 0.45%

0.55 to 1.0%

0.45 to 0.55%

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

40 : 30 : 20 : 10

30 : 20 : 30 : 20

50 : 20 : 10 : 20

50 : 20 : 20 : 10

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

Toughness

Stiffness

Strength

Brittleness

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

Acidic

Brittle

Neutral

Basic

29. 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

30. 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%

0.35 to 0.45%

0.6 to 0.8%

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

Ductility

Malleability

Plasticity

Elasticity

32. The coke in the charge of blast furnace

Supplies heat to reduce ore and melt the iron

Forms a slag by combining with impurities

Acts as an iron bearing mineral

Controls the grade of pig iron

33. Taps dies and drills contain carbon

Above 1%

Below 1%

Below 0.5%

Above 2.2%

34. The usual composition of a soldering alloy is

Tin and lead

Tin and copper

Tin, lead and small percentage of antimony

Tin, lead and silver

35. The hardness of steel primarily depends on

Heat treatment employed

Percentage of carbon

Shape of carbides and their distribution in iron

Percentage of alloying elements

36. The tensile strength of wrought iron is maximum

Perpendicular to lines of slag distribution

Uniform in all directions

None of the above

Along the lines of slag distribution

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

Malleability

Plasticity

Ductility

Brittleness

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

B.C.C. crystalline structure

H.C.P. structure

F.C.C. crystal structure

A complex cubic structure

39. Ductility of a material can be defined as

All of the above

Ability to recover its original form

Ability to undergo large permanent deformations in compression

Ability to undergo large permanent deformations in tension

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

It has good machining properties

It can be forged

It is prone to age hardening

It is lighter than pure aluminium

Engineering Materials Practice Set-3

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