Questions and Answers Section 1

Questions and Answers

Question :


1.The compressive strength of cast iron is more than that of its

Show Answer

tensile strength.

Note:-

Compressive strength or compression strength is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to tensile strength, which withstands loads tending to elongate.

Question :


2.When a steel containing less than 0.8% carbon is cooled slowly from temperatures above or within the critical range, it consists of

Show Answer

ferrite and pearlite

Note:-

Pearlite is a two-phased, layered structure composed of alternating layers of ferrite (88 wt%) and cementite (12 wt%) that occurs in some steels and cast irons.

Question :


3.Eutectoid reaction occurs at

Show Answer

723°C

Note:-

A eutectoid reaction is a three-phase reaction by which, on cooling, a solid transforms into two other solid phases at the same time. If the bottom of a single-phase solid field closes (and provided the adjacent two-phase fields are solid also), it does so with a eutectoid point.

Question :


4.Nickel when added to copper improves

Show Answer

hardness

Note:-

Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion.

Question :


5.In the lower part of the blast furnace (zone of fusion), the temperature is

Show Answer

1200°C to 1300°C

Question :


6.Which of the following impurity in cast iron promotes graphite nodule formation and increases the fluidity of the molten metal?

Show Answer

Silicon

Note:-

Silicon is a chemical element with symbol Si and atomic number 14. A hard and brittle crystalline solid with a blue-grey metallic luster, it is a tetravalent metalloid and semiconductor.

Question :


7.Inconel contains

Show Answer

80% nickel, 14% chromium and 6% iron

Note:-

Inconel is a family of austenitic nickel-chromium-based superalloys. Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected to pressure and heat. Inconel alloys are typically used in high temperature applications.

Question :


8.In a hardening process, the hypo-eutectoid steel is

Show Answer

heated from 30° C to 50° C above the upper critical temperature and then cooled suddenly in a suitable cooling medium.

Note:-

Hardening is a metallurgical metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain. A harder metal will have a higher resistance to plastic deformation than a less hard metal.

Question :


9.The ratio of the volume occupied by the atoms to the total volume of the unit cell is called

Show Answer

atomic packing factor

Note:-

In crystallography, atomic packing factor (APF), packing efficiency or packing fraction is the fraction of volume in a crystal structure that is occupied by constituent particles.

Question :


10.The property of a material which enables it to retain the deformation permanently, is called

Show Answer

plasticity

Note:-

In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces.