Viva Questions of Materials in Basic Mechanical Engineering
Viva Questions of Materials in Basic Mechanical, Materials based Viva Questions, Basic Mechanical Engineering Viva Questions, Engineering Viva Questions,
Short Type Questions and Answers
Q. 1.Classify the engineering materials of construction.
Ans.Engineering materials of construction can be classified as
(1) Metallic materials : (a) Ferrous material (b) Non- ferrous material
(2) Non-metallic materials: (a) Organic material (b) Non-organic material.
Q. 2.What are the mechanical properties of material?
Ans.The mechanical properties of materials define the behavior of materials under the action of external forces, called loads. They are a measure of the strength and lasting characteristics of a material.
Q. 3.Define the term ‘strength’ of a material.
Ans.The strength of a material is its capacity to withstand the action of external loads. The stronger the material the greater the load it can withstand.
Q. 4.What is elasticity?
Ans.Elasticity is that property of a material by virtue of which deformation caused by applied load disappears upon removal of the load.
Q. 5.Define the ‘stiffness’ of a material.
Ans.The resistance of a material to elastic deformation or deflection is called the high degree of stiffness or rigidity.
Q. 6.What do you mean by Ductility and Malleability is a property of an engineering material?
Ans.Ductility is the property of a material that enables it to draw out into thin wire. Mild steel is a ductile material.
The malleability of a material is its ability to be flattened into its sheets without cracking by hot or cold working. Aluminum, copper, tin, lead, steel, etc. are malleable metals.
Q. 7.What is Resilience?
Ans.Resilience is the capacity of a material to absorb potential energy within the elastic range. On removal of the load, the energy stored is given off exactly as in spring when the load is removed.
Q. 8.Explain the terns “Toughness” for an engineering material.
Ans.Toughness is a measure of the amount of energy a material can absorb before fracture or failure takes place.
Q. 9.Explain the terms hardness, hardenability and Brittleness.
Ans.Hardness is a fundamental property that is closely related to strength. Hardness is usually defined in terms of the ability of a material to resist, scratching, abrasion, cutting, indentation, or penetration.
Hardenability indicates the degree of hardness that can be imparted to metal by the process of hardening.
The brittleness of a material is the property of breaking without much permanent distortion.
Q. 10.What is “Creep”?
Ans.It is the property of engineering material. It can be defined as “The slow and progressive deformation of a material with time at constant stress.” The simplest type of creep deformation is viscous flow.
Ans.Fatigue is defined as the failure of a given material when it is subjected to the stresses of the cyclic nature. By fatigue failure occurs much before the yield point of the given material.
Q.12.What are ferrous metals? How are they classified?
Ans.Ferrous metals are those which have iron as their main constituent. They are basically classified as cast iron, wrought iron, steels, and alloy steels.
Q. 13.What are steels? Classify the different steels.
Ans.Steel is an alloy of iron, carbon, and several other elements. Like manganese, Silicon is an important constituent because of its ability to increase the hardness and strength of steel. Steel may be classified as:
1. Low carbon steel (mild steel)
2. Medium carbon steel
3. High carbon steel.
Q.14.What are the properties of tool steel?
Ans.Tool steel is very hard. It must be heated and wear-resistant. Heat resistance is the property of preserving hardness and cutting ability at the high temperature arising in cutting. Wear resistance is the property of retaining shape and size during the cutting.
Q.15.Explain the effect of alloying chromium and nickel in stainless steel.
Ans. The addition of nickel and chromium increases the tensile strength and increases in resistance to corrosion takes place.
Q. 16.What is the percentage of carbon in cast iron?
Q. 17.Distinguish between creep and fatigue.
Ans.Creep is low and progressive deformation of a material with time under constant stress at high-temperature applications. Fatigue is the reduced tendency of material to offer resistance to applied stress under repeated or fluctuating loading condition.
Q. 18.List two effects of manganese in plain carbon steels.
Ans.Manganese increases tensile strength and hardness. It decreases weldability.