1) During heat treatment when carbon is dissolved to form solid solution, it is known as

Ferrite

Pearlite

Austenite

Cementite

Correct Answer- (C)

2) Which one of the following is the solid carburizing material?

Charcoal

Petrol

Ammonia

Kerosene

Correct Answer- (A)

3) While hardening, after heating the steel to the required temperature, it is held at that temperature as soaking time for normally

5 minutes for 10 mm thickness

10 minutes for 5 mm thickness

2 minutes for 20 mm thickness

20 minutes for 2 mm thickness

Correct Answer- (A)

4) Which one of the following quenching media is used for hardening H.S.S. tool?

Water

Brine solution

Oil

Soda water

Correct Answer- (C)

5) What is the hardening temperature for H.S.S. tool?

1250°C

950°C

850°C

750°C

Correct Answer- (A)

6) Which one of the following is the purpose of tempering a hardened steel component ?

To increase toughness

To increase ductility

To increase hardness

To reduce hardness

Correct Answer- (A)

7) While normalizing the steel should be cooled

in still air to room temperature

in oil

by forced air

in water

Back

Next

Correct Answer- (A)

8) The process of increasing carbon percentage on the surface of tow-carbon steel is known as

Hardening

Nitriding

Carburizing

Tempering

Correct Answer- (C)

9) The process of producing a component with tough and ductile core and a hard outer surface is known as

Hardening

Case hardening

Tempering

Annealing

Correct Answer- (B)

10) The process of heating steel to about 40°C above the upper critical temperature and cooling it in still air to room temperature is known as

Hardening

Annealing

Normalizing

Tempering

Correct Answer- (C)

11) Which one of the following heat treatment processes produces a scale-free surface on the component?

Flame hardening

Case hardening

Nitriding

Induction hardening

Correct Answer- (D)

12) In heat treatment process annealing is done to

increase the toughness

increase the softness

increase the hardness

increase the brittleness

Correct Answer- (B)

13) After hardening process, the metal becomes more hardened and also will become more

Brittle

Ductile

Malleable

Tough

Correct Answer- (A)

14) For case hardening the first stage is carburising. By carburising it s meant…

Increasing the percentage of carbon of the steel piece

Increasing the percentage of carbon of the core of the piece

Increasing the percentage of carbon on the surface

Decreasing the percentage of carbon of the steel piece

Correct Answer- (C)

15) For annealing hypoeutectoid steel according to the carbon content, it should be heated to

30°C to 50°C above the lower critical point

30°C to 50°C above the upper critical point

600°C to 630°C

1000°C to 1030°C

Correct Answer- (B)

16) Liquid carburising is done in a heated salt bath. Which one of the following is not a carburising salt?

Sodium carbonate

Sodium sulphate

Sodium cyanide

Barium chloride

Correct Answer- (A)

17) For best result of annealing, the heated steel piece is cooled

slowly in the furnace itself by switching off the heat supply

by removing the piece from the furnace and allowing it to cool in open air

be removing the piece from the furnace and placing it under a blast of air

by removing the piece from the furnace and dipping it in a tank containing water

Correct Answer- (A)

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