Engineering Materials Practice Set-6

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1. Malleable cast iron is produced

By quick cooling of molten cast iron

From white cast iron by annealing process

By adding magnesium to molten cast iron

None of these

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

Ductility

Carbon content

Compressive strength

Hardness

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

Does not effect

Increases

None of these

Decreases

4. Wrought iron is

Highly resistant to corrosion

Heat treated to change its properties

Hard

High in strength

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

Flakes

Spheroids

Cementite

Free carbon

6. Grey cast iron has

High tensile strength

Low compressive strength

Carbon in the form of free graphite

All of these

7. 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

8. In induction hardening ________ is high.

Current

Frequency

Temperature

Voltage

9. The crystal structure of gamma iron is

Face centered cubic

Body centered cubic

Cubic structure

Hexagonal close packed

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

2%

0.2%

1.3%

0.8%

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11. When the steel is normalized, its

Ultimate tensile strength increases

Ductility decreases

All of these

Yield point increases

12. Steel containing ferrite and pearlite is

Tough

Hard

Hard and tough

Soft

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

Nodular aggregates of graphite

Flakes

Free carbon

Cementite

14. Manganese is added in low carbon steel to

Raise the yield point

Make the steel tougher and harder

Make the steel ductile and of good bending qualities

All of the above

15. Combined carbon in iron makes the metal

Soft and gives coarse grained crystalline structure

Hard and gives a coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

Soft and gives a fine grained crystalline structure

16. Cast iron has

High ductility

Its elastic limit close to the ultimate breaking strength

All of the above

High tensile strength

17. Monel metal is an alloy of

Nickel, Chromium and iron

Nickel and chromium

Copper and chromium

Nickel and copper

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

Cementite

Flakes

Spheroids

Free carbon

19. Paramagnetic alpha iron changes to gamma iron at

910°C

1539°C

1440°C

770°C

20. Iron is

Ferromagnetic

Paramagnetic

Dielectric

Ferroelectric

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21. Chilled cast iron has

No graphite

Graphite as its basic constituent of composition

A very high percentage of graphite

A low percentage of graphite

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

White metal

Silicon bronze

Phosphor bronze

Monel metal

23. The unique property of cast iron is its high

Surface finish

Damping characteristics

Malleability

Ductility

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

Copper

Magnesium

Nickel

Chromium

25. Pick up wrong statement about wrought iron

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

It contains carbon of the order of 0 to 0.25%

It is very soft and ductile

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

Molybdenum

Vanadium

Cobalt

Nickel

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

Hexagonal close packed lattice

Body centered cubic lattice

All of the above

Face centered cubic lattice

28. The lower critical temperature

Increases as the carbon content in steel increases

Is same for all steels

Depends upon the rate of heating

Decreases as the carbon content in steel increases

29. The crystal of alpha iron is

Face centered cubic

Cubic structure

Hexagonal close packed

Body centered cubic

30. 'Killed steels' are those steels

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

Which are destroyed by burning

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31. In mottled cast iron, carbon is available in

Combined form

Free form

Nodular form

Partly in free and partly in combined state

32. Which of the following is an amorphous material?

Lead

Mica

Glass

Silver

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

Critical temperature

Melting point

Hardness

Yield point

34. 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

35. Annealing of white cast iron results in production of

Malleable iron

Spheroidal iron

Grey iron

Nodular iron

36. Gamma iron exits at following temperature

Room temperature

Between 910°C and 1400°C

Near melting point

Between 1400°C and 1539°C

37. Carbon steel is

Made by adding carbon in steel

Refined from cast iron

Extensively used for making cutting tools

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

38. Induction hardening is basically a

Carburising process

Surface hardening process

None of these

Core hardening process

39. Pure iron is the structure of

Austenite

Ferrite and cementite

Ferrite

Pearlite

40. Sulphur in pig iron tends to make it

Tough

Soft

Hard

Ductile

Engineering Materials Practice Set-6

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