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4

Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called

A. Tempering

B. Hardening

C. Annealing

D. Normalising

Correct Answer :

C. Annealing


Related Questions

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4

The hardenability of steel decreases with

A. Decrease in dislocation density

B. Increase in solutionising temperature

C. Increase in strength

D. Decrease in grain size

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4

Property responsible for the talcum powder to cling to the skin is the

A. Capillary action

B. Adhesion

C. Cohesion

D. Surface tension

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4

Specific gravity of a metal, which weighs 5 kg in air and 4 kg when submerged in water, will be

A. 5

B. 1.25

C. 2.5

D. 3.75

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4

The ratio of the shear stress to the principal stress on a principal plane is

A. 0

B. 1

C. 1/2

D. 1/3

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4

Solidification time of a molten metal in a casting is proportional to (where, V = volume of metal & A = its surface area; in the casting)

A. V/A

B. V/A2

C. V2/A

D. V2/A2

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4

The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the 'Curie temperature'. Its value for cobalt is __________ °C.

A. 768

B. 1127

C. 1359

D. 1480

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4

The concentration of (H+) ions is 4 x 10-5 in a solution. Then pH of the solution will be (Given log 4 = 0.6)

A. 4.4

B. 5.6

C. 8.4

D. 2.4

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4

Pick out the wrong statement.

A. Weldability of high carbon steel is poorer compared to low carbon steel

B. Invar is a magnetic alloy

C. Magnetic permeability of the diamagnetic material is less than one

D. Martenistic transformation never goes to completion (i.e., 100%) at room temperature

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4

A polymer is termed as an 'elastomer', if its percentage elongation is more than 100%. An elastomer is termed as 'rubber' if its percentage elongation is more than __________ percent.

A. 150

B. 200

C. 300

D. 400

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4

__________ property of a material is determined by the Herbert Pendulum device.

A. Hardness

B. Tensile

C. Toughness

D. Compressive

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4

Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.

A. Atoms

B. Neutrons

C. Nucleons

D. Electrons

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4

Addition of __________ to steel does not impart hardness.

A. Nickel

B. Copper

C. Chromium

D. Silicon

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4

The rolling process cannot be used to produce

A. Plates

B. Rods

C. Tubes

D. Wires

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4

In case of brasses, with decreasing zinc percentage and increasing copper percentage, its __________ increases.

A. Percentage elongation

B. Brinell hardness

C. Tensile strength

D. All 'a', 'b' & 'c'

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4

Referring to the periodic table of elements, it is found that with increasing atomic number. The atomic size in the same

A. Period increases

B. Period decreases

C. Group increases

D. Both 'b' & 'c'

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4

Steel rods are normally used for concrete reinforcement because concrete and steel have almost equal

A. Tensile strength

B. Compressive strength

C. Young's modulus

D. Thermal co-efficient of expansion

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4

The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe)

A. A

B. D

C. 1/A

D. 1/A2

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4

The noble metals

A. Are exemplified by Na, K and Li

B. Do not resist corrosion very strongly

C. Are the lowermost in the electro-chemical series of metals

D. None of these

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4

Insulation of liquid surface can be achieved by __________ on top of its surface.

A. Floating hollow polypropylene spheres

B. Spraying alumina powder

C. Putting cement

D. None of these

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4

Thermal equivalent of electrical power in practical calculation is __________ kcal/kWh.

A. 746

B. 3000

C. 1000

D. 550

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4

In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will

A. Decrease gradually

B. Increase gradually

C. Increase rapidly

D. Remain constant

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4

Which one is neutral in character?

A. N2O4

B. N2O

C. N2O5

D. N2O3

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4

Superheating of steam is done at constant

A. Enthalpy

B. Entropy

C. Pressure

D. Volume

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4

Stellite is a __________ material.

A. Ferrous

B. Ceramic

C. Cemented carbide

D. Non-ferrous cast alloy cutting tool

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4

As the fluid flow rate increases, the float of the Rotameter

A. Rises in the tube

B. Rotates at higher speed

C. Rotates at lower speed

D. Drops down in the tube

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4

The lightest non-inflammable gas is

A. H2

B. He

C. Ar

D. O2

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4

Carbide tipped cutting tools are manufactured by powder metallurgy techniques and have a composition of

A. 90% tungsten carbide and 10% cobalt

B. 70% aluminium oxide & 30% silica

C. 30% nickel, 15% chromium & 55% tungsten

D. 65% tungsten & 35% zirconium

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4

In troposphere (the weather domain), the temperature 't' at height 'h' above the sea level in metres is given by (where, temperature at sea level is 15°C and t is in °C.)

A. t = 15 - 0.0065 h

B. t = 15 + 0.0065 h

C. t = 0.0035 h - 15

D. t = 15 - 0.0035 h

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4

One ton of refrigeration is not equivalent to the heat removal rate of

A. 200 BTU/minute

B. 50 kcal/minute

C. 50 kJ/sec

D. 3.5 KW

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4

The highest stress that a material can withstand for a specified length of time without excessive deformation is called the __________ strength.

A. Creep

B. Endurance

C. Fatigue

D. None of these