Frequently asked top Mechanical Engineering Interview Questions and answers on Material Science (MS) and Heat Treatment (HT) for Freshers and 2-5 year Experienced Mechanical Engineers. For students, viva questions are also provided.
1) What do you mean by Smelting ?
Process of extraction of iron is called Smelting.
2) What do you understand by Specific Gravity and Tenacity ?
- Specific Gravity . It is the ratio of the mass of 1cubic cm. of a substance to the mass of the same capacity of water.
- Tenacity .It is the property of metal due to which a metal becomes strong enough to resist the pulling force.
3) Define the following metal properties (a) Machinability (b)Malleability
- (a) Machinability is the property of metal due to which a metal can easily be cut by cutting tools to obtain good surface finish. E.g.: Brass, Mild steel
- (b) Malleability is the property of the metal on account of which it can be extended in all directions by hammering or rolling. E.g.: Tin, Lead
4) Define Hardness of the metal ?
It is the property of the metal which makes a metal capable to resist surface penetration by other metals .Hard metals are High carbon steel and High speed steel.
5) What is the Toughness of metal ?
Toughness is the property of metal due to which without fracture a metal is able to withstand bending or torsion. Mild steel and wrought iron are tough metals.
6) Define the following properties of metal : (a) Fusibility (b) Stiffness (c) Ductility
- Fusibility. It is the property of metal due to which a metal becomes fluid when it is heated.
- Stiffness. It is the property of metal due to which a metal is capable of resisting deflection due to an externally applied load.
- Ductility. It is the property of metal due to which a metal can be drawn into the form of wires without rupture.
7) Why are cast iron seasoned before machining ?
For easy machining and saving the cutting edge of the tool.
8) How does carbon affects the properties of steel ?
If carbon content is higher the degree of hardness is more and the melting point is lower, If carbon percentage is lower it is easy to forging and forge welding.
9) Why are machine beds made of cast iron ?
Because it has more compressive strength and negligible shrinkage. It can easily cast into any integral shape, wear resisting and can absorb vibrations.
10) What is the difference between Wrought iron, Cast iron and Pig iron ?
Wrought iron contains less than 0.1% carbon and this is a product of puddling furnace. Cast iron is produced from cupola furnace. It contains 33.5% carbon in combined or free state. Pig iron is an iron carbon alloy contains 35% carbon along with impurities like manganese, sulphur and phosphorous. It is a product of blast furnace.