Which of the following is a case hardening process
During heat treatment of steel, the hardness of various structure in increasing order is
Maximum surface hardness is achieved by
Maximum surface hardness is produced by nitriding followed by cyaniding and carburising.
Tempering is a process of annealing
Tempering is the process of annealing martensite at low temperature. Although martensite is strong and wear resistant, it is brittle. Its toughness is low, primarily because of residual stresses introduced by the transformation. When tempering is carried out at a occurs. The martensite grains retain their strength, but improve their toughness and donot change shape on storage.
Hardness of steel greatly improves with
Annealing, Normalizing and Tempering are not hardening process hardening is done by cyaniding process.
Primary objective of full annealing is to
The primary objective of the full annealing is to reduce the hardness and brittleness or to improve ductility of the material.
Carburized machine components have high endurance limit because carburization
Tempering temperature of most of the material is of the order of
Tempering process is categorised in three category
Case hardening is the only method suitable for hardening
Which of the following materials cannot be heat treated
The machine tool guide ways are hardened by
The Iron-carbon diagram and the TTT curves are determined under
Iron-carbon diagram are draw in equilibrium condition that is why it is also called iron-carbon equilibrium diagram while T-T-T diagram is drawn for non-equilibrium conditions.
Cast steel crankshaft surface is hardened by
TTT diagram indicates time, temperature and transformation of
When the temperature of a solid metal increases
The main purpose of spheroidising treatment is to improve
The essential constituent of a hardened steel is
Martensite is an essential constituent of hardened steel.
Which of the following is defined as the ability of the structure to transform into martensite?
Hardenability is defined as the ability of the structure to transform into martensite.
Normalizing of steel is done by
The heat treatment process used for hardening of steel is
Microstructure of annealed hypereutectoid plain carbon steel consists of
Which one of the following cooling methods is best suited for converting Austenite steel into very fine Peariite steel?
The oil quenching is the best suited for Austenite steel into very fine pearlite steel.
Doubling the frequency of current in an induction hardening process
“Matching Exercise”. Choose the correct one out of the alternatives A, B, C, D.
Heat treatment process
R. Martempering sizes
1. Surface hardening
2. Relieving stress
3. Refining grain
4. Reducing warping and cracking
Match List-I (Heat Treatment) with List-ll (Effect on the properties) and select the correct answer using the codes given below the lists:
1. Refined grain structure
2. Improves the hardness of the whole mass
3. Increases surface hardness
4. Improves ductility
A B C D
(a) 4 3 2 1
(b) 1 3 4 2
(c) 4 2 1 3
(d) 2 1 3 4
Annealing is softening process which improves ductility. Normalizing is cooling of material in air so it refines grain structures (due to faster cooling than annealing) Nitriding is employed with alloy steel in which different alloys forms their respective nitrides so surface hardness improves.
Match List-I (Name of treatment) with List-ll (Media used) and select the correct answer using the codes given below the lists:
A. Pack carburising
B. Gas carburising
1. Ammonia gas
2. Sodium cyanide
3. Carburising compound
A B C D
(a) 3 4 2 1
(b) 2 1 3 4
(c) 3 1 2 4
(d) 2 4 3 1
Match List-I (Temperature) with List-ll (Tempering) and select the correct answer using the codes given below the lists:
A. Low temperature tempering
B. Medium temperature tempering
C. High temperature tempering
1. 150°C to 250°C
2. 250°C to 350°C
3. 350°C to 450°C
4. 500°C to 650°C
A B C
(a) 1 2 3
(b) 1 2 4
(c) 2 3 4
(d) 4 3 1
Which one of the following advantage of cyaniding is incorrect?
Globular form of cementite is the structure of steel is obtained through
Presence of hydrogen in steel causes