HEAT TREATMENT MCQ 1
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
