Engineering Materials Practice Set-6

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1. The purpose of heat treatment is to

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

Any one of these

Change grain size

Modify the structure of the material

2. Annealing of white cast iron results in production of

Spheroidal iron

Nodular iron

Malleable iron

Grey iron

3. 'Killed steels' are those steels

Which after their destruction are recycled to produce fresh steel

Which are destroyed by burning

In which carbon is completely burnt

Which are deoxidized in the ladle with silicon and aluminium

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

Ductility

Carbon content

Hardness

Compressive strength

5. Paramagnetic alpha iron changes to gamma iron at

1539°C

910°C

1440°C

770°C

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

Free carbon

Flakes

Cementite

Spheroids

7. Pick up wrong statement about wrought iron

It melts at 1535°C

It contains carbon of the order of 0 to 0.25%

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

It is very soft and ductile

8. The unique property of cast iron is its high

Surface finish

Malleability

Ductility

Damping characteristics

9. Monel metal is an alloy of

Copper and chromium

Nickel, Chromium and iron

Nickel and copper

Nickel and chromium

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

White metal

Monel metal

Silicon bronze

Phosphor bronze

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11. The crystal structure of gamma iron is

Hexagonal close packed

Cubic structure

Body centered cubic

Face centered cubic

12. Induction hardening is basically a

Core hardening process

Carburising process

None of these

Surface hardening process

13. Steel containing ferrite and pearlite is

Soft

Hard and tough

Tough

Hard

14. The lower critical temperature

Increases as the carbon content in steel increases

Is same for all steels

Decreases as the carbon content in steel increases

Depends upon the rate of heating

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

Flakes

Nodular aggregates of graphite

Free carbon

Cementite

16. Chilled cast iron has

A low percentage of graphite

Graphite as its basic constituent of composition

No graphite

A very high percentage of graphite

17. Sulphur in pig iron tends to make it

Soft

Ductile

Hard

Tough

18. Grey cast iron has

Carbon in the form of free graphite

High tensile strength

All of these

Low compressive strength

19. Wrought iron is

Highly resistant to corrosion

High in strength

Hard

Heat treated to change its properties

20. Pure iron is the structure of

Ferrite

Pearlite

Austenite

Ferrite and cementite

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

Free carbon

Cementite

Spheroids

Flakes

22. The crystal of alpha iron is

Face centered cubic

Body centered cubic

Cubic structure

Hexagonal close packed

23. Manganese is added in low carbon steel to

Raise the yield point

Make the steel ductile and of good bending qualities

All of the above

Make the steel tougher and harder

24. Combined carbon in iron makes the metal

Soft and gives coarse grained crystalline structure

Hard and gives a coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

Hard and gives a fine grained crystalline structure

25. Malleable cast iron is produced

None of these

From white cast iron by annealing process

By adding magnesium to molten cast iron

By quick cooling of molten cast iron

26. Carbon steel is

Made by adding carbon in steel

Extensively used for making cutting tools

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

Refined from cast iron

27. In induction hardening ________ is high.

Temperature

Voltage

Frequency

Current

28. Which of the following is an amorphous material?

Lead

Mica

Silver

Glass

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

0.8%

1.3%

0.2%

2%

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

Molybdenum

Nickel

Cobalt

Vanadium

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

Yield point

Melting point

Hardness

Critical temperature

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

All of the above

Body centered cubic lattice

Hexagonal close packed lattice

Face centered cubic lattice

33. In mottled cast iron, carbon is available in

Free form

Nodular form

Partly in free and partly in combined state

Combined form

34. Gamma iron exits at following temperature

Between 910°C and 1400°C

Near melting point

Between 1400°C and 1539°C

Room temperature

35. Cast iron has

Its elastic limit close to the ultimate breaking strength

All of the above

High tensile strength

High ductility

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

Nickel

Chromium

Copper

Magnesium

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

All of these

Internal stresses are relieved

Steels are heated to 500 to 700°C

Cooling is done slowly and steadily

38. When the steel is normalized, its

All of these

Yield point increases

Ultimate tensile strength increases

Ductility decreases

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

Does not effect

None of these

Decreases

Increases

40. Iron is

Dielectric

Paramagnetic

Ferromagnetic

Ferroelectric

Engineering Materials Practice Set-6

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