1) The purpose of normalizing steel is to
improve machinability
soften the steel
increase the toughness and reduce Brittleness
remove induced stresses
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
3) A given component cracked after heat treatment. What can be the possible reason?
It was heated for a long time
It was not properly cleaned before heating
It was slowly cooled in air
It was suddenly cooled in a brine
4) Case hardening is a method of producing hard skin on the surface of steel are
High-carbon steel parts
Cast iron (heavy parts)
Alloy steel parts
Low-carbon steel parts
5) To reduce internal stresses of a hardened tool, the method of heat treatment generally applied is
Stabilising
Annealing
Normalising
6) The toughness in steel is increased and brittleness is decreased by a heat treatment operation called as
Annealing
Normalizing
Case hardening
7) In a case hardening process, ammonia gas is introduced on steel; the process is known as
Cyaniding
Carburizing
Nitriding
Ammonising
8) Cyaniding “and “Nitriding” are two methods of
Hardening
Tempering
Case hardening
Normalizing
9) After heating up to required hardening temperature, why must tool steels be quenched?
To induce internal stresses
To fall off the scale
To build up hardening structure
To return it to its original structure
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 slowly quenched
The punch is suddenly quenched
The punch is too little heated
11) Heat treatment of metals is necessary
To make a good appearance on the component
To increase the strength of the metal
To make the metal rust-proof
To produce certain desired properties
12)The external surface of the part made of mild steel can be hardened by
Tempering
Normalizing
Hardening
13) In the nitriding process, the NH3 gas is introduced at
575°C to 600°C
600°C to 650°C
650°C to 700°C
500°C to 560°C
14) H.S.S. is tempered at
220°C to 230°C
230°C to 270°C
280°C to 400°C
15) The instrument used to measure high temperature in the furnace is
Thermometer
Barometer
Colorimeter
16) Which one of the following processes is used for hardening the surface of tool steel?
Carburizing
Cyaniding
Hardening
Induction Hardening
17) The lower critical temperature of high carbon steel while hardening is
960°C
900°C
723°C
560°C
18) The approximate hardness of HSS milling cutter is
45 HRC
52 HRC
62 HRC
75 HRC
19) The purpose of the heat treatment is
To change the internal structure of steel
To change the appearance of the component.
To change the mechanical properties of steel.
To change the chemical properties of steel.
20) One component of C50 steel is heated to 830°C, soaked at it for some time and then quenched in oil. Again it is heated to 600°C and quenched in oil. Name this process of heat treatment.
Annealing
Normalizing
Case hardening
21) Which one of the following processes is adapted to improve the internal structure of steel, which has been subjected to severe hammering?
Hardening
Annealing
Normalizing
Tempering
22) Which one of the following structures of steel is obtained due to the drastic cooling from the austenite structure?
Pearlite
Cementite
Martensite
Troostite
23) Which one of the following processes by which steel is heated to the required temperature and then cooled slowly in the furnace itself?
Tempering
Hardening
Annealing
Nitriding
25) What is the main purpose of annealing?
To improve magnetism
To increase hardness
To improve machinability
To increase toughness
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