MCQ’s On Heat treatment of Metals and Alloys
Q. What is the melting point of pure iron?
A. 1500°C
B. 1535°C
C. 1570°C
D. 1605°C
.
.Answer: B
Explanation: Process Iron exists in many allotropic forms, and every such allotropic form has a different melting, boiling and solidifying point. But, for pure iron, the melting point is 1535°C.
Q. Which iron is formed when the melt is frozen?
A. Alpha
B. Beta
C. Gamma
D. Delta
.
..Answer: D
Explanation: Process Alpha irons, beta irons or gamma irons cannot be formed when the metal is in the frozen form. When the molten metal is frozen, delta iron is formed.
Q. What is the kind of lattice in a delta iron?
A. Face centered cubic
B. Body centered cubic
C. Hexagonal closely packed
D. Tetragonal closely packed
.
.Answer: B
Explanation: Process The delta form of solid state of iron, which is formed on cooling the melt, has a body centered cubic lattice structure.
Q. What is the kind of lattice in a gamma iron?
A. Face centered cubic
B. Body centered cubic
C. Hexagonal closely packed
D. Tetragonal closely packed
.
.Answer: A
Explanation: Process The gamma form of solid state of iron, which is formed on cooling the melt, has a face centered cubic lattice structure.
Q. In transformation in steel, hypo eutectoid steel are heated up to what temperature?
A. 677°C
B. 700°C
C. 723°C
D. 746°C
.
.Answer: C
Explanation: Process In transformation in steel, the hypo eutectoid steels are heated up to a very high amount of temperature. The temperature to which they are taken is 723°C.
Q. What is the Brinell hardness of pearlite?
A. 150
B. 180
C. 210
D. 240
.
.Answer: B
Explanation: Process Pearlite is not the hardest form. The Brinell hardness of pearlite is only 180. There is a harder material than pearlite, called as martensite, which has Brinell hardness ranging from 650-700.
Q. The alpha iron is highly non-magnetic.
A. True
B. False
.
.Answer: B
Explanation: Process It is one of the properties of alpha irons that alpha irons are highly magnetic and they are found to exist only at room temperature. The alpha iron is the fourth retardation of iron.
Q. How much is the Brinell hardness of martensite?
A. 600-650
B. 650-700
C. 750-800
D. 800-850
.
.Answer: B
Explanation: Process Martensite is a ferro-magnetic substance in nature, and it is known to have Brinell hardness ranging from 650-700.
Q. What is the value of ‘a’ in a delta iron lattice?
A. Q.00 Å
B. Q.93 Å
C. Q.00 Å
D. Q.93 Å
.
.Answer: B
Explanation: Process The value of a, which is the distance between two consecutive atoms in the lattice, in delta iron lattice is calculated to be Q.93 Å, which is around Q.93 x 10-10 meters.
Q. Alpha iron exists only in high temperature and pressure conditions.
A. True
B. False
.
.Answer: B
Explanation: Process It is one of the properties of alpha irons that alpha irons are highly magnetic and they are found to exist only at room temperature.
Q. HPF steel is normalized at what temperature?
A. 800°C
B. 900°C
C. 1000°C
D. 1100°C
.
.Answer: B
Explanation: Process The HPF steel has to be taken to high magnitudes of temperatures. The HPF steel or the hot press forming steel gets normalized at 900°C.
Q. What is the Vicker’s hardness of steel before the HPF Process?
A. 150 Hv
B. 160 Hv
C. 170 Hv
D. 180 Hv
.
.Answer: C
Explanation: Process The HPF Process in steels is considered to be a very important Process, it involves heating the steel to high temperatures. The Vickers hardness of steel before HPF Process is 170 Hv.
Q. What is the Vickers hardness of steel after the HPF Process?
A. 362 Hv
B. 462 Hv
C. 562 Hv
D. 662 Hv
.
.Answer: B
Explanation: Process The HPF Process is a very essential Process. The Vickers hardness of the material is found to change after this Process is done. The Vickers hardness of steel after HPF Process is 462 Hv.
Q. What is the amount of carbon used in HPF steel?
A. Less than 0.37%
B. Less than 0.27%
C. Less than 0.47%
D. Less than 0.57%
.
.Answer: B
Explanation: Process The carbon content which is used in HPF steel is very less in percentage composition. The amount of carbon used in terms of percentage weight is less than 0.27%.
Q. What is the amount of silicon used in HPF steel?
A. Less than 0.30%
B. Less than 0.20%
C. Less than 0.40%
D. Less than 0.50%
.
..Answer: D
Explanation: Process The silicon content which is used in HPF steel is very less in percentage composition. The amount of silicon used in terms of percentage weight is less than 0.50%.
Q. What is the amount of boron used in HPF steel?
A. Less than 0.003%
B. Less than 0.007%
C. Less than 0.009%
D. Less than 0.057%
.
.Answer: A
Explanation: Process The boron content which is used in HPF steel is extremely less in percentage composition. The amount of boron used in terms of percentage weight is less than 0.003%.
Q. What is the amount of tungsten used in HPF steel?
A. Less than 0.03%
B. Less than 0.02%
C. Less than 0.04%
D. Less than 0.05%
.
..Answer: D
Explanation: Process The tungsten content which is used in HPF steel is very less in terms of percentage composition. The amount of tungsten used in terms of percentage weight is less than 0.05%.
Q. What is the amount of nitrogen used in HPF steel?
A. Less than 0.03%
B. Less than 0.02%
C. Less than 0.04%
D. Less than 0.05%
.
.Answer: B
Explanation: Process The nitrogen content which is used in HPF steel is very less in percentage composition. The amount of nitrogen used in terms of percentage weight is less than 0.02%.
Q. In an inverse rate curve for steel, steel is heated uniformly.
A. True
B. False
.
.Answer: A
Explanation: Process In an inverse rate curve for steel, the steel is not just heated uniformly, also its temperature is recorded.
Q. In an HPF steel, the amount of manganese used is 3% by weight.
A. True
B. False
.
.Answer: B
Explanation: Process The manganese content which is used in HPF steel is comparatively more than other substances in percentage composition. The amount of manganese used for HPF steel is less, approximately about, Q.5% to Q.0%.
Q. Which of the following Processes is called as quenching?
A. Slow cooling
B. Slow heating
C. Rapid cooling
D. Rapid heating
.
.Answer: C
Explanation: Process Among the following, that is, slow cooling, slow heating, rapid cooling and rapid heating, quenching is the name given to the Process of rapid cooling.
Q. On martensite formation, what is the percentage increase in the volume of the steel?
A. 3%
B. 13%
C. 23%
D. 33%
.
.Answer: A
Explanation: Process It has been observed that whenever there is a formation of martensite, there is some amount of increase in the volume accompanied by it. This increase in the volume is about 3%.
Q. How much is the Brinell hardness of sorbite?
A. 250
B. 350
C. 450
D. 550
.
.Answer: B
Explanation: Process The cementite in sorbite is known to be very finely divided. The material sorbite is not one of the hardest materials known in casting. The Brinell hardness of sorbite is 350.
Q. How much is the Brinell hardness of troostite?
A. 250
B. 350
C. 450
D. 550
.
.Answer: C
Explanation: Process The cementite in the troostite is very finely divided. The material troostite is not one of the hardest materials known in casting. The Brinell hardness of sorbite is 450.
Q. What is the chemical formula of cementite?
A. Fe3O4
B. Fe2O3
C. Fe3C
D. FeSO4
.
Q. What is the crystal structure of cementite?
A. Orthogonal
B. Pyramidal
C. Trapeziodal
D. Orthorhombic
.
..Answer: D
Explanation: Process The crystal structure of the compound cementite or iron carbide is not orthogonal or pyramidal or trapezoidal, but it is orthorhombic.
Q. What is the curie temperature of cementite?
A. 480K
B. 500K
C. 520K
D. 540K
.
.Answer: A
Explanation: Process The compound cementite is also called as Iron Carbide. The chemical formula of the compound cementite is Fe3C. The curie temperature of the compound cementite is approximately about 480K.
Q. What is the percentage weight of iron in cementite?
A. 9Q.3%
B. 9Q.3%
C. 9Q.3%
D. 9Q.3%
.
.Answer: A
Explanation: Process In the compound iron carbide or cementite, the percentage weight of iron is 9Q.3% and the rest of the space in the lattice is occupied by carbon. By weight, carbon is present in about Q.67% in the mixture.
Q. What is the percentage weight of carbon in cementite?
A. Q.53%
B. Q.67%
C. Q.23%
D. Q.39%
.
.Answer: B
Explanation: Process None.
Q. Cementite is a brittle material.
A. True
B. False
.
.Answer: A
Explanation: Process Cementite, when in its purest form, is used as a ceramic. Cementite or iron carbide is considered to be a brittle material.
Q. Heat treatment is a Process which alters the mechanical properties of metal by changing the product shape.
A. True
B. False
.
.Answer: B
Explanation: Process Heat treatment is basically a combination of heating and cooling operations applied to a metal in the solid state in a way to alter their physical and mechanical properties. This method enhances the mechanical properties of metal and the whole Process is accomplished by without changing the shape of metal which being treated.
Q. Case hardening of non-ferrous materials can be done easily as compared to that of ferrous materials.
A. True
B. False
.
.Answer: B
Explanation: Process In general, all the heat treatment Processes are similar as they all include heating and cooling of metals. The heat treatment of ferrous materials normally includes Processes like annealing, normalizing, hardening, or tempering. But for nonferrous metals, tempering, normalizing or case hardening cannot be done, they only goes through an annealing Process.
Q. Proper equipment with close control must be implemented in the heat treatment of metals.
A. True
B. False
.
.Answer: A
Explanation: Process In heat treatment of materials, it must include proper equipment with close control over the parts relevant to the heating and cooling. For example, the furnace should be of proper shape and size and should be kept within the prescribed limits for each operation. The material used for the heat treatment should be finished and of appropriate size.
Q. In heat treatment of metals, quenching is a method which induces ductility in the metal.
A. True
B. False
.
.Answer: B
Explanation: Process Quenching is a Process in which heated metal product interacts directly with cooled water. In heat treatment of metals, this method is used for static load purposes as this Process makes the metal hard and brittle. The brittleness basically induced in the metal due to the formation of fine grains on the metal surface.
Q. The heating rate of metals mainly depends on the thermal conductivity of metal which being treated.
A. True
B. False
.
.Answer: A
Explanation: Process In heat treatment of metals, first stage involves heating of metals in which metal is uniformly heated with appropriate heating rate. The heating rate of metal mainly depends on the thermal conductivity of metal and also depends on the metal condition like its size and cross-section.
Q. In heat treatment, soaking is a stage in which metal product is cleaned by finishing operation.
A. True
B. False
.
.Answer: B
Explanation: Process In heat treatment of metals, soaking is a stage which includes holding of metal to the appropriate temperature until the required internal structural changes occur. And soaking period is a term used for the time the metal is held at the specific temperature. For the determination of soaking period, a chemical analysis of the metal is done.
Q. In heat treatment of materials, the purpose of annealing is totally opposite to that of hardening.
A. True
B. False
.
.Answer: A
Explanation: Process In general, the purpose of annealing is just the opposite of hardening. In annealing Process, metal is treated to relieve internal stresses and to get soften or ductile by refining their grain structures. And the purpose of hardening is to harden the metal, which also increases its strength by decreasing its ductility.
Q. For annealing of ferrous materials, the material is heated with a faster rate to get the desired properties.
A. True
B. False
.
.Answer: B
Explanation: Process The objective of annealing Process is mainly is to induce ductility or softness in the material. To anneal ferrous materials (iron is base metal), the metal is slowly heated to its proper temperature. Then after soaking Process, the material is cooled very slowly by placing heated metal part in an insulating material.
Q. In the heat treatment, normalizing method cannot be applicable for non-ferrous materials.
A. True
B. False
.
.Answer: A
Explanation: Process The objective of normalizing is to remove internal stresses from the material being treated. Normalizing can be applicable to ferrous materials, but it cannot be used for treating non-ferrous materials. In normalizing, the metal is heated to a higher temperature and then it is removed from the furnace for air cooling.
Q. Carburizing is a case hardening Process in which carbon is added to the surface of a metal.
A. True
B. False
.
.Answer: A
Explanation: Process Carburizing is a case hardening Process in which carbon is added to the metal surface. In the Process of carburizing, when the metal is heated in a container with charcoal, the case becomes very hard and the inside core remains soft and tough. Then the metal part is removed from the furnace for air cooling.
Q. Which of the following is not an objective of annealing?
A. Softening of steel
B. Hardening of steel
C. Increase ductility
D. Relieve internal stress
.
.Answer: B
Explanation: Process Among the many purposes of treating the steel through annealing is softening of steel, hardening of steel and relieving the internal stresses, but annealing is not used for hardening of the steel.
Q. In full annealing, the steel is heated at what temperature?
A. Above critical temperature
B. Above vaporization temperature
C. Above liquefying temperature
D. Above solidification temperature
.
.Answer: A
Explanation: Process In the Process of full annealing, the steel has to be heated slightly above the critical temperature. At this point, the steel has to be held for a considerable amount of time.
Q. In annealing Process, for the formation of hypereutectoid steel, the steel has to be heated above what point?
A. Ac1
B. Ac2
C. Ac3
D. Ac4
.
.Answer: A
Explanation: Process For the formation of hypereutectoid steel, in annealing Process, the steel has to be heated above the Ac1 point, which is the lower critical line in the temperature versus carbon content graph.
Q. In annealing Process, for the formation of hypoeutectoid steel, the steel has to be heated above what point?
A. Ac1
B. Ac2
C. Ac3
D. Ac4
.
.Answer: C
Explanation: Process None.
Q. For how long is the heated steel held in full annealing Process?
A. 1 minute
B. 3 minutes
C. 6 minutes
D. 9 minutes
.
.Answer: B
Explanation: Process The heated steel is held at the critical temperature for about 3 to 4 minutes. By doing this, the steel gets enough time to make the internal changes desired.
Q. In full annealing, the metal cannot be buried in which of the following materials?
A. Sand
B. Lime
C. Ashes
D. Manganese powder
.
..Answer: D
Explanation: Process In the Process, full annealing, if the metal is removed at high temperatures, they need to be buried. For this, the material cannot be manganese powder.
Q. Annealing is a fast Process.
A. True
B. False
.
.Answer: B
Explanation: Process Annealing is considered to be a very slow Process, as the part where the steel is cooled, takes up a lot of time for the Process to get completed.
Q. Which of the following is also called as diffusion annealing?
A. Isothermal annealing
B. Process annealing
C. Homogenizing
D. Spheroidise annealing
.
.Answer: C
Explanation: Process Homogenising has another name as diffusion annealing. This method is applied to both the ingots, carbon as well as alloy steel.
Q. At what temperature is homogenizing carried out?
A. 1150°C
B. 1370°C
C. 1420°C
D. 1320°C
.
.Answer: A
Explanation: Process Homogenizing is carried out between temperature ranges of 1100°C to 1200°C, but the most optimum temperature is 1150°C, at which the diffusion Process goes ahead smoothly.
Q. Normalizing Process takes a lot of time to complete.
A. True
B. False
.
.Answer: B
Explanation: Process Normalizing is a comparatively faster Process than annealing, as in this Process, the cooling rate is supposed to be very high, causing the Process to end in lesser time.
