1) The purpose of normalizing steel is to

remove induced stresses

improve machinability

soften the steel

increase the toughness and reduce Brittleness

Correct Answer- (A)

2) A carbon steel piece is heated just above 730°C, maintained at that temperature for a few hours and then slowly cooled. What heat treatment process is carried out?

Normalizing

Casehardening

Hardening

Annealing

Correct Answer- (D)

3) A given component cracked after heat treatment. What can be the possible reason?

It was heated for long time

It was not properly cleaned before heating

It was suddenly cooled in brine

It was slowly cooled in air

Correct Answer- (C)

4) Case hardening is a method of producing hard skin on the surface of steel are

High-carbon steel parts

Cast iron (heavy parts)

Low-carbon steel parts

Alloy steel parts

Correct Answer- (C)

5) To reduce internal stresses of a hardened tool, the method of heat treatment generally applied is

Stabilising

Annealing

Normalising

Tempering

Correct Answer- (D)

6) The toughness in a steel is increased and brittleness is decreased by a heat treatment operation called as

Annealing

Normalizing

Tempering

Case hardening

Correct Answer- (C)

7) In a case hardening process, ammonia gas is introduced on steel; the process is known as

Cyaniding

Nitriding

Carburizing

Ammonising

Correct Answer- (B)

8) Cyaniding “and “Nitriding” are two methods of

Hardening

Case hardening

Tempering

Normalising

Correct Answer- (B)

9) After heating upto required hardening temperature, why must tool steels be quenched?

To induce internal stresses

To build up hardening structure

To fall off the scale

To return it to its original structure

Correct Answer- (B)

10) A punch is made out of unalloyed steel. After hardening a crack takes place. What can be the reason to develop this crack?

The punch is too long heated

The punch is too little heated

The punch is too slowly quenched

The punch is suddenly quenched

Correct Answer- (B)

11) Heat treatment of metals is necessary

To produce certain desired properties

To make good appearance on the component

To increase strength of the metal

To make the metal rust-proof

Correct Answer- (A)

12)The external surface of the part made of mild steel can be hardened by

Tempering

Normalising

Case hardening

Hardening

Correct Answer- (C)

13) In nitriding process the NH3 gas is introduced at

500°C to 560°C

575°C to 600°C

600°C to 650°C

650°C to 700°C

Correct Answer- (A)

14) H.S.S. is tempered at

220°C to 230°C

230°C to 270°C

280°C to 400°C

550°C to 600°C

Correct Answer- (D)

15) The instrument used to measure high temperature in the furnace is

Thermometer

Barometer

Colorimeter

Pyrometer

Correct Answer- (D)

16) Which one of the following processes is used for hardening the surface of tool steel?

Carburizing

Cyaniding

Induction hardening

Hardening

Correct Answer- (C)

17) Lower critical temperature of high carbon steel while hardening is

960°C

900°C

723°C

560°C

Correct Answer- (C)

18) Approximate hardness of HSS milling cutter is

45 HRC

52 HRC

62 HRC

75 HRC

Correct Answer- (C)

19) The purpose of heat treatment is

To change the mechanical properties of steel.

To change the internal structure of steel

To change the appearance of the component.

To change the chemical properties of steel.

Correct Answer- (A)

20) One component of C50 steel is heated to 830°C, soaked at it for some time andthen quenched in oil. Again it is heated to 600°C and quenched in oil. Name this process of heat treatment.

Annealing

Normalizing

Hardening and tempering

Case hardening

Correct Answer- (C)

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