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Correct answer is (c) Homogenizing

Easy explanation: Homogenising has ANOTHER NAME as diffusion annealing. This METHOD is applied to both the INGOTS, carbon as WELL as alloy steel.

Correct OPTION is (b) False

The best explanation: 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.

The correct OPTION is (d) Manganese powder

The best I can explain: 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.

Right OPTION is (b) False

Explanation: 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.

Correct choice is (b) False

Explanation: 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.

Right CHOICE is (b) HARDENING of steel

Best EXPLANATION: 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.

Correct answer is (d) Less than 0.50%

Easiest explanation: 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%.

The correct choice is (B) 2.93 Å

Explanation: The value of a, which is the distance between two consecutive ATOMS in the lattice, in DELTA IRON lattice is calculated to be 2.93 Å, which is around 2.93 x 10-10 meters.

Right option is (c) 723°C

To ELABORATE: 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.

The correct option is (a) Above critical temperature

For EXPLANATION I WOULD say: 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.

The correct option is (a) True

The explanation: 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.

Correct option is (b) False

The best explanation: 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.

Correct option is (b) 900°C

Explanation: 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.

The correct ANSWER is (b) 462 Hv

Explanation: 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.

The correct choice is (B) Body centered CUBIC

The best I can explain: The delta FORM of solid state of iron, which is formed on cooling the melt, has a body centered cubic LATTICE structure.

The CORRECT option is (a) True

Best explanation: 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.

Right answer is (b) False

To elaborate: 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.

Right option is (b) False

The best I can explain: 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.

Right choice is (d) Orthorhombic

Best explanation: The CRYSTAL STRUCTURE of the compound CEMENTITE or iron CARBIDE is not orthogonal or PYRAMIDAL or trapezoidal, but it is orthorhombic.

The correct answer is (b) False

The EXPLANATION: 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, 1.5% to 2.0%.

The CORRECT option is (c) RAPID cooling

Explanation: 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.

The correct CHOICE is (b) False

To elaborate: 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.

The CORRECT option is (b) LESS than 0.02%

The best I can explain: 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%.

Correct option is (a) 3%

The EXPLANATION is: 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%.

Right choice is (a) True

Explanation: 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.

The correct answer is (a) True

Best explanation: 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.

Right ANSWER is (B) Less than 0.27%

For EXPLANATION I would say: 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%.

The correct choice is (B) 180

The best I can EXPLAIN: 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.

The correct choice is (d) DELTA

The EXPLANATION: 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.

Right ANSWER is (b) 1535°C

For explanation: 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.

The CORRECT ANSWER is (B) 6.67%

To EXPLAIN: NONE.

The correct choice is (b) False

To elaborate: 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.

Right answer is (a) Ac1

For explanation I would SAY: 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.

Right choice is (a) LESS than 0.003%

EASY explanation: 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%.

The correct answer is (a) 480K

For explanation I would say: 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.

Correct CHOICE is (a) True

To EXPLAIN: In an inverse rate curve for STEEL, the steel is not just HEATED uniformly, also its temperature is recorded.