Engineering Materials Practice Set-6

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1. The lower critical temperature

Increases as the carbon content in steel increases

Depends upon the rate of heating

Decreases as the carbon content in steel increases

Is same for all steels

2. 'Killed steels' are those steels

Which after their destruction are recycled to produce fresh steel

In which carbon is completely burnt

Which are destroyed by burning

Which are deoxidized in the ladle with silicon and aluminium

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

Cobalt

Molybdenum

Vanadium

Nickel

4. Which of the following is an amorphous material?

Glass

Silver

Mica

Lead

5. Malleable cast iron is produced

None of these

From white cast iron by annealing process

By quick cooling of molten cast iron

By adding magnesium to molten cast iron

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

Hexagonal close packed lattice

Body centered cubic lattice

Face centered cubic lattice

All of the above

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

Magnesium

Copper

Nickel

Chromium

8. Steel containing ferrite and pearlite is

Hard and tough

Soft

Hard

Tough

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

None of these

Decreases

Increases

Does not effect

10. Grey cast iron has

All of these

Carbon in the form of free graphite

High tensile strength

Low compressive strength

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11. Chilled cast iron has

A low percentage of graphite

No graphite

A very high percentage of graphite

Graphite as its basic constituent of composition

12. Manganese is added in low carbon steel to

Make the steel tougher and harder

All of the above

Make the steel ductile and of good bending qualities

Raise the yield point

13. The crystal structure of gamma iron is

Hexagonal close packed

Cubic structure

Body centered cubic

Face centered cubic

14. When the steel is normalized, its

Ultimate tensile strength increases

All of these

Ductility decreases

Yield point increases

15. Wrought iron is

Highly resistant to corrosion

High in strength

Hard

Heat treated to change its properties

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

Flakes

Free carbon

Spheroids

Cementite

17. Iron is

Dielectric

Paramagnetic

Ferromagnetic

Ferroelectric

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

Melting point

Yield point

Critical temperature

Hardness

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

Cementite

Spheroids

Free carbon

Flakes

20. Annealing of white cast iron results in production of

Spheroidal iron

Grey iron

Malleable iron

Nodular iron

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

Silicon bronze

Monel metal

Phosphor bronze

White metal

22. Induction hardening is basically a

Surface hardening process

None of these

Carburising process

Core hardening process

23. Cast iron has

High tensile strength

High ductility

Its elastic limit close to the ultimate breaking strength

All of the above

24. The crystal of alpha iron is

Body centered cubic

Cubic structure

Face centered cubic

Hexagonal close packed

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

Compressive strength

Ductility

Carbon content

Hardness

26. Sulphur in pig iron tends to make it

Hard

Soft

Tough

Ductile

27. Monel metal is an alloy of

Nickel and copper

Nickel and chromium

Copper and chromium

Nickel, Chromium and iron

28. 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

29. The purpose of heat treatment is to

Any one of these

Modify the structure of the material

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

Change grain size

30. Pure iron is the structure of

Pearlite

Austenite

Ferrite and cementite

Ferrite

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

Nodular aggregates of graphite

Flakes

Cementite

Free carbon

32. In induction hardening ________ is high.

Current

Voltage

Frequency

Temperature

33. Combined carbon in iron makes the metal

Soft and gives coarse grained crystalline structure

Soft and gives a fine grained crystalline structure

Hard and gives a coarse grained crystalline structure

Hard and gives a fine grained crystalline structure

34. Paramagnetic alpha iron changes to gamma iron at

910°C

770°C

1440°C

1539°C

35. The unique property of cast iron is its high

Ductility

Damping characteristics

Malleability

Surface finish

36. 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 is very soft and ductile

It contains carbon of the order of 0 to 0.25%

It melts at 1535°C

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

0.2%

1.3%

0.8%

2%

38. In mottled cast iron, carbon is available in

Partly in free and partly in combined state

Free form

Combined form

Nodular form

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

All of these

Internal stresses are relieved

Steels are heated to 500 to 700°C

Cooling is done slowly and steadily

40. Gamma iron exits at following temperature

Near melting point

Room temperature

Between 1400°C and 1539°C

Between 910°C and 1400°C

Engineering Materials Practice Set-6

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