Engineering Materials Practice Set-6

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

Cementite

Flakes

Spheroids

Free carbon

2. The purpose of heat treatment is to

Any one of these

Modify the structure of the material

Change grain size

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

3. Wrought iron is

Heat treated to change its properties

High in strength

Highly resistant to corrosion

Hard

4. 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 contains carbon of the order of 0 to 0.25%

It is very soft and ductile

5. In induction hardening ________ is high.

Current

Temperature

Voltage

Frequency

6. Grey cast iron has

Carbon in the form of free graphite

Low compressive strength

All of these

High tensile strength

7. The unique property of cast iron is its high

Malleability

Ductility

Surface finish

Damping characteristics

8. Monel metal is an alloy of

Nickel and chromium

Nickel, Chromium and iron

Copper and chromium

Nickel and copper

9. When the steel is normalized, its

Yield point increases

Ductility decreases

All of these

Ultimate tensile strength increases

10. Induction hardening is basically a

Carburising process

Core hardening process

None of these

Surface hardening process

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11. Paramagnetic alpha iron changes to gamma iron at

770°C

1440°C

910°C

1539°C

12. 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

13. Manganese is added in low carbon steel to

Raise the yield point

All of the above

Make the steel tougher and harder

Make the steel ductile and of good bending qualities

14. 'Killed steels' are those steels

Which after their destruction are recycled to produce fresh steel

In which carbon is completely burnt

Which are deoxidized in the ladle with silicon and aluminium

Which are destroyed by burning

15. Gamma iron exits at following temperature

Room temperature

Near melting point

Between 910°C and 1400°C

Between 1400°C and 1539°C

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

Free carbon

Cementite

Nodular aggregates of graphite

Flakes

17. Which of the following is an amorphous material?

Silver

Glass

Mica

Lead

18. Carbon steel is

Extensively used for making cutting tools

Refined from cast iron

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

Made by adding carbon in steel

19. In mottled cast iron, carbon is available in

Nodular form

Free form

Partly in free and partly in combined state

Combined form

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

0.2%

1.3%

0.8%

2%

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21. The crystal of alpha iron is

Cubic structure

Face centered cubic

Body centered cubic

Hexagonal close packed

22. Sulphur in pig iron tends to make it

Ductile

Soft

Hard

Tough

23. Cast iron has

High tensile strength

All of the above

High ductility

Its elastic limit close to the ultimate breaking strength

24. The lower critical temperature

Increases as the carbon content in steel increases

Decreases as the carbon content in steel increases

Depends upon the rate of heating

Is same for all steels

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

Critical temperature

Melting point

Yield point

Hardness

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

Ductility

Hardness

Compressive strength

Carbon content

27. Steel containing ferrite and pearlite is

Hard and tough

Soft

Tough

Hard

28. The crystal structure of gamma iron is

Face centered cubic

Cubic structure

Body centered cubic

Hexagonal close packed

29. Chilled cast iron has

Graphite as its basic constituent of composition

A very high percentage of graphite

No graphite

A low percentage of graphite

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

Nickel

Chromium

Copper

Magnesium

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31. Combined carbon in iron makes the metal

Soft and gives coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

Hard and gives a coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

32. Annealing of white cast iron results in production of

Spheroidal iron

Nodular iron

Malleable iron

Grey iron

33. Pure iron is the structure of

Pearlite

Ferrite

Austenite

Ferrite and cementite

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

Cooling is done slowly and steadily

All of these

Internal stresses are relieved

Steels are heated to 500 to 700°C

35. Malleable cast iron is produced

By adding magnesium to molten cast iron

None of these

From white cast iron by annealing process

By quick cooling of molten cast iron

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

Decreases

Increases

Does not effect

None of these

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

Cementite

Flakes

Free carbon

Spheroids

38. Iron is

Dielectric

Ferromagnetic

Ferroelectric

Paramagnetic

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

Nickel

Cobalt

Vanadium

Molybdenum

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

Monel metal

Silicon bronze

Phosphor bronze

White metal

Engineering Materials Practice Set-6

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