Engineering Materials Practice Set-6

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1. Cast iron has

High ductility

Its elastic limit close to the ultimate breaking strength

High tensile strength

All of the above

2. Carbon steel is

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

Extensively used for making cutting tools

Refined from cast iron

Made by adding carbon in steel

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

Copper

Magnesium

Nickel

Chromium

4. Pure iron is the structure of

Austenite

Ferrite and cementite

Ferrite

Pearlite

5. The unique property of cast iron is its high

Ductility

Damping characteristics

Malleability

Surface finish

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

Carbon content

Hardness

Compressive strength

Ductility

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

All of the above

Hexagonal close packed lattice

Body centered cubic lattice

Face centered cubic lattice

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

0.8%

2%

0.2%

1.3%

9. Gamma iron exits at following temperature

Near melting point

Between 1400°C and 1539°C

Room temperature

Between 910°C and 1400°C

10. The crystal structure of gamma iron is

Body centered cubic

Face centered cubic

Hexagonal close packed

Cubic structure

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11. In mottled cast iron, carbon is available in

Partly in free and partly in combined state

Free form

Nodular form

Combined form

12. Pick up wrong statement about wrought iron

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

It melts at 1535°C

It is very soft and ductile

It contains carbon of the order of 0 to 0.25%

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

Critical temperature

Hardness

Melting point

Yield point

14. Which of the following is an amorphous material?

Silver

Glass

Lead

Mica

15. The crystal of alpha iron is

Face centered cubic

Body centered cubic

Hexagonal close packed

Cubic structure

16. Induction hardening is basically a

Core hardening process

Carburising process

None of these

Surface hardening process

17. The purpose of heat treatment is to

Change grain size

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

Any one of these

Modify the structure of the material

18. Chilled cast iron has

No graphite

A low percentage of graphite

Graphite as its basic constituent of composition

A very high percentage of graphite

19. 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

20. Iron is

Ferroelectric

Dielectric

Ferromagnetic

Paramagnetic

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

Flakes

Free carbon

Spheroids

Cementite

22. Annealing of white cast iron results in production of

Nodular iron

Spheroidal iron

Grey iron

Malleable iron

23. When the steel is normalized, its

Ductility decreases

Ultimate tensile strength increases

All of these

Yield point increases

24. 'Killed steels' are those steels

Which are deoxidized in the ladle with silicon and aluminium

In which carbon is completely burnt

Which are destroyed by burning

Which after their destruction are recycled to produce fresh steel

25. Manganese is added in low carbon steel to

Make the steel tougher and harder

Raise the yield point

All of the above

Make the steel ductile and of good bending qualities

26. Sulphur in pig iron tends to make it

Tough

Ductile

Hard

Soft

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

All of these

Internal stresses are relieved

Cooling is done slowly and steadily

Steels are heated to 500 to 700°C

28. Malleable cast iron is produced

None of these

By adding magnesium to molten cast iron

From white cast iron by annealing process

By quick cooling of molten cast iron

29. Combined carbon in iron makes the metal

Soft and gives a fine grained crystalline structure

Hard and gives a coarse grained crystalline structure

Soft and gives coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

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

Increases

Does not effect

Decreases

None of these

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

White metal

Phosphor bronze

Monel metal

Silicon bronze

32. Steel containing ferrite and pearlite is

Hard

Soft

Tough

Hard and tough

33. In induction hardening ________ is high.

Frequency

Temperature

Voltage

Current

34. Wrought iron is

Highly resistant to corrosion

Heat treated to change its properties

Hard

High in strength

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

Spheroids

Cementite

Free carbon

Flakes

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

Flakes

Cementite

Free carbon

Nodular aggregates of graphite

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

Cobalt

Molybdenum

Vanadium

Nickel

38. Monel metal is an alloy of

Copper and chromium

Nickel, Chromium and iron

Nickel and copper

Nickel and chromium

39. Grey cast iron has

All of these

Low compressive strength

High tensile strength

Carbon in the form of free graphite

40. Paramagnetic alpha iron changes to gamma iron at

910°C

1539°C

1440°C

770°C

Engineering Materials Practice Set-6

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