Question 1

An eutectoid steel consists of

Accepted Answer

Eutectoid steel, at the eutectoid composition (about 0.76% carbon), consists wholly of pearlite when cooled slowly to room temperature. Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of ferrite and cementite that forms from austenite during the eutectoid transformation.

Question 2

In normalizing, one of the following is not correct

Accepted Answer

Normalizing involves heating a metal to a specific temperature and then allowing it to cool in air, which results in a moderate rate of cooling, not slow.

Question 3

Fine grain sizes are obtained by

Accepted Answer

A

Question 4

Which one of the following is not the purpose of full annealing

Accepted Answer

Full annealing is a heat treatment process aimed at refining grains, inducing softness, and removing strains and stresses in metals. It does not produce the hardest material; instead, it makes the material softer and more ductile.

Question 5

Annealing is generally done to impart

Accepted Answer

Annealing is a heat treatment process used to reduce hardness, increase ductility, and help eliminate internal stresses in a material, making it softer and more workable.

Question 6

Which of the following processes is used to harden a steel?

Accepted Answer

Quenching is a process used to harden steel by heating it to a high temperature and then rapidly cooling it, typically in water or oil. This rapid cooling changes the steel's microstructure, increasing its hardness and strength.

Question 7

The hardness of quenched Martensite

Accepted Answer

The answer of The hardness of quenched Martensite
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Question 8

Dispersion hardening materials can be produced with the help of followinf process

Accepted Answer

Dispersion hardening materials are often produced using powder metallurgy, which allows for the uniform distribution of fine particles within a metal matrix, enhancing its strength and hardness.

Question 9

in case of carbonitriding by diffusion of which elements the surface become harder of the metal

Accepted Answer

Carbonitriding involves the diffusion of both carbon and nitrogen into the surface of the metal to increase its hardness. This process is a variation of the traditional case hardening technique that adds nitrogen to the carburizing process, enhancing surface properties such as wear resistance and fatigue strength.

Question 10

in case of flame hardening the heat source in the form of

Accepted Answer

Flame hardening typically uses an oxy-acetylene flame as the heat source because it can produce a very high temperature, allowing for rapid heating of the steel surface to be hardened.

Question 11

in jominy end quench test sample is quenched by

Accepted Answer

In the Jominy end quench test, the sample is typically quenched using water to assess the hardenability of steel.

Question 12

martempering is also known as

Accepted Answer

Martempering is also known as marquenching. It is a heat treatment technique that aims to reduce the stresses and cracking risks associated with quenching by cooling the material at a moderate rate within a specific temperature range.

Question 13

In martempering heat treatment, the final phase which obtain

Accepted Answer

Martempering results in the formation of martensite, which is not listed among the options.

Question 14

In petenting process, which is the final phase obtainafter completion of heat treatment

Accepted Answer

The answer of In petenting process, which is the final...

Question 15

which of the following metal alloy is suitable for the precipitation hardenable alloy.

Accepted Answer

Al-Cu (Aluminum-Copper) alloys are well-known for their ability to be precipitation hardened, which involves heat treatment to enhance their strength and hardness.

Question 16

Pearlite is harder than ferrite,this statement is-------

Accepted Answer

Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of ferrite and cementite (iron carbide, Fe3C) that occurs in some steels and cast irons. It forms by a controlled cooling process from the austenite phase. Pearlite is harder and stronger than ferrite due to the presence of cementite, which is a very hard material.

Question 17

Cementite is harder than pearlite,this statement id -------

Accepted Answer

Cementite (Fe3C) is a compound of iron and carbon, and it is much harder than pearlite, which is a mixture of ferrite and cementite in a lamellar structure.

Question 18

The Atomic structure of austenite phase is

Accepted Answer

Austenite has a face-centered cubic (f.c.c) crystal structure.

Question 19

The Atomic structure of martensite is

Accepted Answer

Martensite has a body-centered tetragonal (b.c.t) crystal structure. This structure is a result of the diffusionless transformation of austenite into martensite in steel and other alloys, leading to a hard and brittle phase.

Question 20

In case of annealing heat treatment process hypoeutectoid steels are heated above --------- temperature

Accepted Answer

In the annealing heat treatment process, hypoeutectoid steels are heated above the Ac3 temperature. This is the temperature at which the steel's structure changes from ferrite and pearlite to austenite, allowing for the desired changes in mechanical properties through controlled cooling.

Quiz 1: Heat Treatment Processes for Steel