Engineering Materials Practice Set-6

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

Nickel

Copper

Magnesium

Chromium

2. Induction hardening is basically a

Carburising process

None of these

Surface hardening process

Core hardening process

3. 'Killed steels' are those steels

Which are deoxidized in the ladle with silicon and aluminium

In which carbon is completely burnt

Which after their destruction are recycled to produce fresh steel

Which are destroyed by burning

4. In mottled cast iron, carbon is available in

Combined form

Nodular form

Partly in free and partly in combined state

Free form

5. Pick up wrong statement about wrought iron

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%

It melts at 1535°C

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

All of these

Cooling is done slowly and steadily

Internal stresses are relieved

Steels are heated to 500 to 700°C

7. Steel containing ferrite and pearlite is

Tough

Soft

Hard

Hard and tough

8. Monel metal is an alloy of

Nickel, Chromium and iron

Nickel and chromium

Copper and chromium

Nickel and copper

9. 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

10. The crystal of alpha iron is

Hexagonal close packed

Cubic structure

Body centered cubic

Face centered cubic

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

Melting point

Critical temperature

Yield point

Hardness

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

Phosphor bronze

Monel metal

White metal

Silicon bronze

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

Ductility

Hardness

Carbon content

Compressive strength

14. In induction hardening ________ is high.

Current

Voltage

Temperature

Frequency

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

Does not effect

None of these

Increases

Decreases

16. Cast iron has

All of the above

Its elastic limit close to the ultimate breaking strength

High ductility

High tensile strength

17. Wrought iron is

High in strength

Hard

Heat treated to change its properties

Highly resistant to corrosion

18. The purpose of heat treatment is to

Change grain size

Any one of these

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

Modify the structure of the material

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

Nickel

Cobalt

Molybdenum

Vanadium

20. The unique property of cast iron is its high

Damping characteristics

Ductility

Malleability

Surface finish

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21. Grey cast iron has

All of these

Carbon in the form of free graphite

High tensile strength

Low compressive strength

22. Chilled cast iron has

Graphite as its basic constituent of composition

No graphite

A low percentage of graphite

A very high percentage of graphite

23. Paramagnetic alpha iron changes to gamma iron at

910°C

770°C

1440°C

1539°C

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

Cementite

Flakes

Free carbon

Nodular aggregates of graphite

25. Pure iron is the structure of

Austenite

Pearlite

Ferrite

Ferrite and cementite

26. 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

27. Which of the following is an amorphous material?

Glass

Silver

Lead

Mica

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

Face centered cubic lattice

Hexagonal close packed lattice

All of the above

Body centered cubic lattice

29. The crystal structure of gamma iron is

Face centered cubic

Cubic structure

Body centered cubic

Hexagonal close packed

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

Flakes

Cementite

Free carbon

Spheroids

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31. Annealing of white cast iron results in production of

Malleable iron

Nodular iron

Grey iron

Spheroidal iron

32. Malleable cast iron is produced

From white cast iron by annealing process

By adding magnesium to molten cast iron

By quick cooling of molten cast iron

None of these

33. Carbon steel is

Refined from cast iron

Extensively used for making cutting tools

Made by adding carbon in steel

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

34. When the steel is normalized, its

Ultimate tensile strength increases

All of these

Ductility decreases

Yield point increases

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

Flakes

Spheroids

Free carbon

Cementite

36. Manganese is added in low carbon steel to

Make the steel ductile and of good bending qualities

Raise the yield point

All of the above

Make the steel tougher and harder

37. Sulphur in pig iron tends to make it

Tough

Soft

Ductile

Hard

38. Gamma iron exits at following temperature

Between 910°C and 1400°C

Room temperature

Between 1400°C and 1539°C

Near melting point

39. Iron is

Ferromagnetic

Paramagnetic

Dielectric

Ferroelectric

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

1.3%

0.2%

2%

0.8%

Engineering Materials Practice Set-6

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