Engineering Materials Practice Set-6

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1. Iron is

Paramagnetic

Dielectric

Ferroelectric

Ferromagnetic

2. Pure iron is the structure of

Ferrite and cementite

Austenite

Ferrite

Pearlite

3. The crystal of alpha iron is

Body centered cubic

Face centered cubic

Hexagonal close packed

Cubic structure

4. Which of the following is an amorphous material?

Mica

Lead

Silver

Glass

5. In induction hardening ________ is high.

Current

Frequency

Voltage

Temperature

6. Steel containing ferrite and pearlite is

Hard and tough

Soft

Tough

Hard

7. Chilled cast iron has

No graphite

A very high percentage of graphite

Graphite as its basic constituent of composition

A low percentage of graphite

8. The following types of materials are usually the most ductile

All of the above

Hexagonal close packed lattice

Face centered cubic lattice

Body centered cubic lattice

9. In mottled cast iron, carbon is available in

Free form

Nodular form

Partly in free and partly in combined state

Combined form

10. In malleable iron, carbon is present in the form of

Cementite

Free carbon

Flakes

Nodular aggregates of graphite

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11. The alloying element which can replace tungsten in high speed steels is

Nickel

Cobalt

Vanadium

Molybdenum

12. Chromium when added to steel _________ the tensile strength.

Decreases

None of these

Does not effect

Increases

13. Sulphur in pig iron tends to make it

Tough

Hard

Soft

Ductile

14. Gamma iron exits at following temperature

Between 1400°C and 1539°C

Near melting point

Room temperature

Between 910°C and 1400°C

15. The unique property of cast iron is its high

Malleability

Surface finish

Ductility

Damping characteristics

16. Pick up wrong statement about wrought iron

It is very soft and ductile

It contains carbon of the order of 0 to 0.25%

It melts at 1535°C

It is made by adding suitable percentage of carbon to molten iron and subjecting the product to repeated hammering and rolling

17. Carbon steel is

Made by adding carbon in steel

An alloy of iron and carbon with varying quantities of phosphorus and sulphur

Extensively used for making cutting tools

Refined from cast iron

18. When the steel is normalized, its

Ultimate tensile strength increases

Yield point increases

All of these

Ductility decreases

19. Paramagnetic alpha iron changes to gamma iron at

1539°C

770°C

910°C

1440°C

20. In nodular iron, graphite is in the form of

Cementite

Free carbon

Flakes

Spheroids

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21. Cast iron is characterized by minimum of following percentage of carbon

2%

0.2%

1.3%

0.8%

22. In grey cast iron, carbon is present in the form of

Flakes

Free carbon

Cementite

Spheroids

23. Monel metal is an alloy of

Nickel and copper

Nickel and chromium

Nickel, Chromium and iron

Copper and chromium

24. Annealing of white cast iron results in production of

Spheroidal iron

Grey iron

Nodular iron

Malleable iron

25. The lower critical temperature

Is same for all steels

Increases as the carbon content in steel increases

Depends upon the rate of heating

Decreases as the carbon content in steel increases

26. Malleable cast iron is produced

By quick cooling of molten cast iron

None of these

By adding magnesium to molten cast iron

From white cast iron by annealing process

27. Cast iron has

High ductility

All of the above

High tensile strength

Its elastic limit close to the ultimate breaking strength

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

Silicon bronze

White metal

Phosphor bronze

Monel metal

29. Wrought iron is

Heat treated to change its properties

Highly resistant to corrosion

High in strength

Hard

30. Manganese is added in low carbon steel to

All of the above

Raise the yield point

Make the steel tougher and harder

Make the steel ductile and of good bending qualities

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31. In high speed steels, manganese is used to tougher the metal and to increase its

Critical temperature

Hardness

Yield point

Melting point

32. Combined carbon in iron makes the metal

Hard and gives a fine grained crystalline structure

Hard and gives a coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

Soft and gives coarse grained crystalline structure

33. The purpose of heat treatment is to

Relieve the stresses set up in the material after hot or cold working

Change grain size

Modify the structure of the material

Any one of these

34. Which of the following statements are true for annealing of steels?

Internal stresses are relieved

All of these

Steels are heated to 500 to 700°C

Cooling is done slowly and steadily

35. 'Killed steels' are those steels

Which after their destruction are recycled to produce fresh steel

Which are deoxidized in the ladle with silicon and aluminium

In which carbon is completely burnt

Which are destroyed by burning

36. The crystal structure of gamma iron is

Face centered cubic

Cubic structure

Hexagonal close packed

Body centered cubic

37. Induction hardening is basically a

Surface hardening process

Carburising process

None of these

Core hardening process

38. Nodular cast iron is produced by adding ________ to the molten cast iron.

Chromium

Copper

Magnesium

Nickel

39. Grey cast iron has

Low compressive strength

All of these

High tensile strength

Carbon in the form of free graphite

40. An important property of malleable cast iron in comparison to grey cast iron is the high

Hardness

Compressive strength

Carbon content

Ductility

Engineering Materials Practice Set-6

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