Engineering Materials Practice Set-6

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1. Carbon steel is

Refined from cast iron

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

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

0.2%

0.8%

2%

1.3%

3. Which of the following is an amorphous material?

Glass

Mica

Silver

Lead

4. 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

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

Face centered cubic lattice

All of the above

Hexagonal close packed lattice

Body centered cubic lattice

6. Annealing of white cast iron results in production of

Malleable iron

Spheroidal iron

Grey iron

Nodular iron

7. The unique property of cast iron is its high

Damping characteristics

Malleability

Ductility

Surface finish

8. Wrought iron is

Heat treated to change its properties

Highly resistant to corrosion

High in strength

Hard

9. Combined carbon in iron makes the metal

Hard and gives a coarse grained crystalline structure

Soft and gives coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

Soft and gives a fine grained crystalline structure

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

Spheroids

Free carbon

Flakes

Cementite

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11. Iron is

Ferromagnetic

Dielectric

Ferroelectric

Paramagnetic

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

Chromium

Magnesium

Nickel

Copper

13. Induction hardening is basically a

Carburising process

Core hardening process

None of these

Surface hardening process

14. Sulphur in pig iron tends to make it

Tough

Ductile

Hard

Soft

15. Paramagnetic alpha iron changes to gamma iron at

1440°C

910°C

1539°C

770°C

16. When the steel is normalized, its

All of these

Ductility decreases

Yield point increases

Ultimate tensile strength increases

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

Increases

Does not effect

None of these

Decreases

18. The crystal of alpha iron is

Cubic structure

Body centered cubic

Hexagonal close packed

Face centered cubic

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

Compressive strength

Hardness

Carbon content

Ductility

20. Steel containing ferrite and pearlite is

Hard

Hard and tough

Soft

Tough

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

Cementite

Nodular aggregates of graphite

Flakes

Free carbon

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

Steels are heated to 500 to 700°C

Internal stresses are relieved

Cooling is done slowly and steadily

All of these

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

Nickel

Cobalt

Vanadium

Molybdenum

24. 'Killed steels' are those steels

Which are destroyed by burning

In which carbon is completely burnt

Which after their destruction are recycled to produce fresh steel

Which are deoxidized in the ladle with silicon and aluminium

25. Pick up wrong statement about wrought iron

It contains carbon of the order of 0 to 0.25%

It is very soft and ductile

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

26. Monel metal is an alloy of

Nickel and chromium

Nickel and copper

Nickel, Chromium and iron

Copper and chromium

27. Chilled cast iron has

A low percentage of graphite

A very high percentage of graphite

Graphite as its basic constituent of composition

No graphite

28. In induction hardening ________ is high.

Temperature

Frequency

Current

Voltage

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

White metal

Monel metal

Silicon bronze

Phosphor bronze

30. The crystal structure of gamma iron is

Body centered cubic

Face centered cubic

Cubic structure

Hexagonal close packed

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31. Pure iron is the structure of

Pearlite

Ferrite

Austenite

Ferrite and cementite

32. The lower critical temperature

Decreases as the carbon content in steel increases

Is same for all steels

Increases as the carbon content in steel increases

Depends upon the rate of heating

33. Gamma iron exits at following temperature

Between 1400°C and 1539°C

Between 910°C and 1400°C

Room temperature

Near melting point

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

Yield point

Melting point

Hardness

Critical temperature

35. In mottled cast iron, carbon is available in

Nodular form

Free form

Partly in free and partly in combined state

Combined form

36. Grey cast iron has

All of these

Carbon in the form of free graphite

Low compressive strength

High tensile strength

37. Manganese is added in low carbon steel to

Make the steel ductile and of good bending qualities

All of the above

Raise the yield point

Make the steel tougher and harder

38. The purpose of heat treatment is to

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

Modify the structure of the material

Change grain size

Any one of these

39. Cast iron has

All of the above

High ductility

High tensile strength

Its elastic limit close to the ultimate breaking strength

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

Spheroids

Flakes

Cementite

Free carbon

Engineering Materials Practice Set-6

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