Engineering Materials Practice Set-6

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

Hardness

Critical temperature

Yield point

Melting point

2. The unique property of cast iron is its high

Malleability

Damping characteristics

Surface finish

Ductility

3. Wrought iron is

High in strength

Highly resistant to corrosion

Heat treated to change its properties

Hard

4. Carbon steel is

Made by adding carbon in steel

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

Extensively used for making cutting tools

Refined from cast iron

5. 'Killed steels' are those steels

Which after their destruction are recycled to produce fresh steel

Which are destroyed by burning

Which are deoxidized in the ladle with silicon and aluminium

In which carbon is completely burnt

6. The crystal of alpha iron is

Hexagonal close packed

Face centered cubic

Cubic structure

Body centered cubic

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

Magnesium

Copper

Chromium

Nickel

8. Manganese is added in low carbon steel to

All of the above

Make the steel tougher and harder

Raise the yield point

Make the steel ductile and of good bending qualities

9. Pure iron is the structure of

Ferrite

Pearlite

Austenite

Ferrite and cementite

10. In mottled cast iron, carbon is available in

Combined form

Free form

Nodular form

Partly in free and partly in combined state

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11. Grey cast iron has

Low compressive strength

High tensile strength

All of these

Carbon in the form of free graphite

12. Iron is

Dielectric

Ferromagnetic

Ferroelectric

Paramagnetic

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

Cementite

Spheroids

Free carbon

Flakes

14. Cast iron has

High ductility

High tensile strength

Its elastic limit close to the ultimate breaking strength

All of the above

15. Malleable cast iron is produced

None of these

From white cast iron by annealing process

By adding magnesium to molten cast iron

By quick cooling of molten cast iron

16. Chilled cast iron has

No graphite

A low percentage of graphite

A very high percentage of graphite

Graphite as its basic constituent of composition

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

0.8%

1.3%

2%

0.2%

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

Nodular aggregates of graphite

Flakes

Free carbon

Cementite

19. 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

20. The lower critical temperature

Decreases as the carbon content in steel increases

Increases as the carbon content in steel increases

Depends upon the rate of heating

Is same for all steels

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21. Monel metal is an alloy of

Nickel and copper

Nickel, Chromium and iron

Nickel and chromium

Copper and chromium

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

Carbon content

Compressive strength

Ductility

Hardness

23. Annealing of white cast iron results in production of

Nodular iron

Grey iron

Spheroidal iron

Malleable iron

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

Increases

Decreases

Does not effect

None of these

25. The crystal structure of gamma iron is

Hexagonal close packed

Body centered cubic

Face centered cubic

Cubic structure

26. When the steel is normalized, its

Ultimate tensile strength increases

Yield point increases

All of these

Ductility decreases

27. 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 a fine grained crystalline structure

Soft and gives coarse grained crystalline structure

28. In induction hardening ________ is high.

Current

Voltage

Frequency

Temperature

29. Steel containing ferrite and pearlite is

Tough

Hard

Hard and tough

Soft

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

Cobalt

Molybdenum

Vanadium

Nickel

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31. Paramagnetic alpha iron changes to gamma iron at

910°C

1440°C

1539°C

770°C

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

Free carbon

Flakes

Spheroids

Cementite

33. Gamma iron exits at following temperature

Between 1400°C and 1539°C

Between 910°C and 1400°C

Room temperature

Near melting point

34. 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%

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

Face centered cubic lattice

Hexagonal close packed lattice

Body centered cubic lattice

All of the above

36. Sulphur in pig iron tends to make it

Ductile

Hard

Soft

Tough

37. Which of the following is an amorphous material?

Mica

Glass

Lead

Silver

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

Phosphor bronze

Silicon bronze

Monel metal

White metal

39. Induction hardening is basically a

Carburising process

Core hardening process

None of these

Surface hardening process

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

Cooling is done slowly and steadily

Steels are heated to 500 to 700°C

Internal stresses are relieved

All of these

Engineering Materials Practice Set-6

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