Engineering Materials Practice Set-6

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1. Chilled cast iron has

No graphite

A very high percentage of graphite

A low percentage of graphite

Graphite as its basic constituent of composition

2. The crystal of alpha iron is

Face centered cubic

Hexagonal close packed

Body centered cubic

Cubic structure

3. Paramagnetic alpha iron changes to gamma iron at

910°C

770°C

1539°C

1440°C

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

Increases

Decreases

Does not effect

None of these

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

Body centered cubic lattice

All of the above

Face centered cubic lattice

Hexagonal close packed lattice

6. 'Killed steels' are those steels

In which carbon is completely burnt

Which are destroyed by burning

Which are deoxidized in the ladle with silicon and aluminium

Which after their destruction are recycled to produce fresh steel

7. Carbon steel is

Refined from cast iron

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

Made by adding carbon in steel

Extensively used for making cutting tools

8. Combined carbon in iron makes the metal

Hard and gives a coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

Soft and gives coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

9. Malleable cast iron is produced

By adding magnesium to molten cast iron

From white cast iron by annealing process

None of these

By quick cooling of molten cast iron

10. In induction hardening ________ is high.

Temperature

Current

Frequency

Voltage

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

0.2%

1.3%

0.8%

2%

12. Pure iron is the structure of

Pearlite

Ferrite

Ferrite and cementite

Austenite

13. In mottled cast iron, carbon is available in

Nodular form

Combined form

Free form

Partly in free and partly in combined state

14. Gamma iron exits at following temperature

Near melting point

Room temperature

Between 910°C and 1400°C

Between 1400°C and 1539°C

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

Silicon bronze

Monel metal

White metal

Phosphor bronze

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

Hardness

Ductility

Compressive strength

Carbon content

17. Annealing of white cast iron results in production of

Malleable iron

Grey iron

Nodular iron

Spheroidal iron

18. 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%

19. Grey cast iron has

Carbon in the form of free graphite

All of these

High tensile strength

Low compressive strength

20. Monel metal is an alloy of

Nickel, Chromium and iron

Copper and chromium

Nickel and copper

Nickel and chromium

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

Hardness

Critical temperature

Yield point

Melting point

22. The crystal structure of gamma iron is

Face centered cubic

Body centered cubic

Hexagonal close packed

Cubic structure

23. Steel containing ferrite and pearlite is

Hard and tough

Tough

Hard

Soft

24. 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

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

Flakes

Free carbon

Cementite

Spheroids

26. Iron is

Ferromagnetic

Dielectric

Paramagnetic

Ferroelectric

27. The purpose of heat treatment is to

Change grain size

Modify the structure of the material

Any one of these

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

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

Nickel

Vanadium

Cobalt

Molybdenum

29. When the steel is normalized, its

Yield point increases

All of these

Ductility decreases

Ultimate tensile strength increases

30. Sulphur in pig iron tends to make it

Ductile

Hard

Tough

Soft

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31. Induction hardening is basically a

Surface hardening process

Core hardening process

Carburising process

None of these

32. The lower critical temperature

Increases as the carbon content in steel increases

Decreases as the carbon content in steel increases

Is same for all steels

Depends upon the rate of heating

33. Cast iron has

High ductility

All of the above

High tensile strength

Its elastic limit close to the ultimate breaking strength

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

Spheroids

Free carbon

Flakes

Cementite

35. The unique property of cast iron is its high

Surface finish

Damping characteristics

Ductility

Malleability

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

Nodular aggregates of graphite

Flakes

Cementite

Free carbon

37. Which of the following is an amorphous material?

Glass

Mica

Silver

Lead

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

Magnesium

Copper

Nickel

Chromium

39. Wrought iron is

Highly resistant to corrosion

High in strength

Heat treated to change its properties

Hard

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

Cooling is done slowly and steadily

All of these

Steels are heated to 500 to 700°C

Internal stresses are relieved

Engineering Materials Practice Set-6

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