Engineering Materials Practice Set-6

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1. The unique property of cast iron is its high

Surface finish

Damping characteristics

Ductility

Malleability

2. Pick up wrong statement about wrought iron

It melts at 1535°C

It is very soft and ductile

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

It contains carbon of the order of 0 to 0.25%

3. When the steel is normalized, its

Ultimate tensile strength increases

Ductility decreases

All of these

Yield point increases

4. Induction hardening is basically a

None of these

Surface hardening process

Carburising process

Core hardening process

5. Steel containing ferrite and pearlite is

Hard

Soft

Hard and tough

Tough

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

Cementite

Flakes

Free carbon

Spheroids

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

Flakes

Free carbon

Spheroids

Cementite

8. Carbon steel is

Extensively used for making cutting tools

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

Made by adding carbon in steel

Refined from cast iron

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

Chromium

Nickel

Magnesium

Copper

10. Grey cast iron has

High tensile strength

Low compressive strength

Carbon in the form of free graphite

All of these

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

Flakes

Free carbon

Nodular aggregates of graphite

Cementite

12. In induction hardening ________ is high.

Current

Temperature

Frequency

Voltage

13. Chilled cast iron has

A low percentage of graphite

A very high percentage of graphite

No graphite

Graphite as its basic constituent of composition

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

Melting point

Yield point

Critical temperature

Hardness

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

Cobalt

Molybdenum

Vanadium

Nickel

16. The crystal of alpha iron is

Hexagonal close packed

Cubic structure

Body centered cubic

Face centered cubic

17. Annealing of white cast iron results in production of

Grey iron

Spheroidal iron

Nodular iron

Malleable iron

18. The purpose of heat treatment is to

Any one of these

Modify the structure of the material

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

Change grain size

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

Compressive strength

Ductility

Hardness

Carbon content

20. Wrought iron is

Hard

Highly resistant to corrosion

High in strength

Heat treated to change its properties

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

All of the above

Body centered cubic lattice

Face centered cubic lattice

Hexagonal close packed lattice

22. Iron is

Ferromagnetic

Dielectric

Ferroelectric

Paramagnetic

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

All of these

Steels are heated to 500 to 700°C

Internal stresses are relieved

Cooling is done slowly and steadily

24. Manganese is added in low carbon steel to

Make the steel tougher and harder

Raise the yield point

Make the steel ductile and of good bending qualities

All of the above

25. The lower critical temperature

Depends upon the rate of heating

Decreases as the carbon content in steel increases

Is same for all steels

Increases as the carbon content in steel increases

26. Malleable cast iron is produced

By quick cooling of molten cast iron

By adding magnesium to molten cast iron

From white cast iron by annealing process

None of these

27. Gamma iron exits at following temperature

Between 910°C and 1400°C

Room temperature

Between 1400°C and 1539°C

Near melting point

28. Paramagnetic alpha iron changes to gamma iron at

770°C

1440°C

1539°C

910°C

29. Combined carbon in iron makes the metal

Hard and gives a fine grained crystalline structure

Soft and gives coarse grained crystalline structure

Hard and gives a coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

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

1.3%

2%

0.8%

0.2%

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31. 'Killed steels' are those steels

Which are destroyed by burning

In which carbon is completely burnt

Which are deoxidized in the ladle with silicon and aluminium

Which after their destruction are recycled to produce fresh steel

32. The crystal structure of gamma iron is

Hexagonal close packed

Cubic structure

Face centered cubic

Body centered cubic

33. Cast iron has

Its elastic limit close to the ultimate breaking strength

High tensile strength

All of the above

High ductility

34. Sulphur in pig iron tends to make it

Tough

Soft

Hard

Ductile

35. Pure iron is the structure of

Austenite

Ferrite and cementite

Ferrite

Pearlite

36. In mottled cast iron, carbon is available in

Combined form

Partly in free and partly in combined state

Nodular form

Free form

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

Does not effect

Decreases

Increases

None of these

38. Which of the following is an amorphous material?

Glass

Mica

Lead

Silver

39. Monel metal is an alloy of

Nickel, Chromium and iron

Nickel and copper

Copper and chromium

Nickel and chromium

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

Phosphor bronze

White metal

Silicon bronze

Monel metal

Engineering Materials Practice Set-6

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