Engineering Materials Practice Set-3

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1. The tensile strength of wrought iron is maximum

None of the above

Along the lines of slag distribution

Uniform in all directions

Perpendicular to lines of slag distribution

2. 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

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

Nickel

Chromium

Silicon

Copper

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

Acidic

Neutral

Basic

Brittle

5. The unit cells

All of the above

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

Contain the smallest number of atoms which when taken together have all the properties of the crystals of the particular metal

6. Tungsten in steel

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

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

Improves cutting ability and reduces hardenability

Improves wear resistance, cutting ability and toughness

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

Bosh

Stack

Hearth

Throat

8. 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

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

0.6 to 0.8%

0.35 to 0.45%

0.04%

0.4 to 0.6%

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

It is lighter than pure aluminium

It has good machining properties

It is prone to age hardening

It can be forged

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

Vanadium, chromium, tungsten

Chromium, titanium, vanadium

Tungsten, titanium, vanadium

Tungsten, chromium, titanium

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

Alpha iron, gamma iron and delta iron

Alpha iron and beta iron

Body centered cubic iron and face centered cubic iron

Alpha iron, beta iron and gamma iron

13. Taps dies and drills contain carbon

Below 1%

Below 0.5%

Above 1%

Above 2.2%

14. Hematite iron ore contains iron about

70%

55%

30%

45%

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

F.C.C. crystal structure

B.C.C. crystalline structure

A complex cubic structure

H.C.P. structure

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

Induce stresses

Improve mechanical properties

Refine grain structure

Reduce segregation in casting

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

1500 VPN

250 VPN

600 VPN

1000 to 1100 VPN

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

Phosphor bronze

Monel metal

White metal

Silicon bronze

19. Ductility of a material can be defined as

Ability to recover its original form

Ability to undergo large permanent deformations in compression

All of the above

Ability to undergo large permanent deformations in tension

20. 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

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21. 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%

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

Toughness

Stiffness

Strength

Brittleness

23. The machinability of steel is improved by adding

Nickel and chromium

Nickel

Sulphur, lead and phosphorus

Chromium

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

Ductility

Malleability

Plasticity

Brittleness

25. The usual composition of a soldering alloy is

Tin and copper

Tin and lead

Tin, lead and silver

Tin, lead and small percentage of antimony

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

0.5 to 1%

1.2%

5 to 7%

2.5 to 4.5%

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

Brass

Cast steel

Admiralty metal

Cast iron

28. Cobalt in steel

Gives ductility, toughness, tensile strength and anti corrosion property

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

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

Magnalium

Y-alloy

Duralumin

Hindalium

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

By crushing into thousands of pieces

In direction perpendicular to application of load

By shearing along oblique plane

By forming a bulge

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31. 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

32. Cementite consist of

13% ferrite and 87% cementite

13% cementite and 87% ferrite

6.67% carbon and 93.33% iron

13% carbon and 87% ferrite

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

Strength

Brittleness

Stiffness

Toughness

34. 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

35. There are fourteen atoms in a unit cell of

Body centered cubic space lattice

None of these

Face centered cubic space lattice

Close packed hexagonal space lattice

36. Corundum contains more than 95%

SiO₂

Al₂O₃

Steel

MgO

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

Malleability

Ductility

Elasticity

Plasticity

38. 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

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

Weldability

Machinability

Hardenability

Formability

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

50 : 20 : 10 : 20

40 : 30 : 20 : 10

50 : 20 : 20 : 10

30 : 20 : 30 : 20

Engineering Materials Practice Set-3

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