Engineering Material and Their Properties: Machine Design

 Engineering Material and Their Properties:

The knowledge of materials and their properties is of great significance for a design engineer.

A Design engineer must be familiar with the effects which the manufacturing processes and heat treatment have on the properties of the materials .

Classification of Engineering Materials :

1. Metals and their alloys

2. Non - metals

Metals may be further classified as -

(a) ferrous metals

(b) non -ferrous metals

Ferrous metals are those which have the iron as their main constituent .

Example : cost iron , wrought iron , steel etc.

Non - ferrous metals are those which have a metal other than iron as their main constituent.

Example : Copper, Aluminium , Broad , Zinc etc.

Selection of Materials for Engineering Purpose :

The selection of a proper material , for engineering purposes , is one of the most difficult problem for the designer .

The following factors should be considered while selecting the material -

1. Availability of the materials

2. Suitablility of the materials for the working conditions in service .

3. The cost of the materials .

A filament of bulb needs a material like tungsten which can withstand high temperature without understanding deformation.

Physical Properties of Materials :

Luster , Colour, Size , Shape , Density , Electric  and thermal conductivity , melting point .

Mechanical Properties of Matels :

1. Strength 

2. Stiffness

3. Elasticity

4. Plasticity

5. Ductility

6. Brittleness

7. Malleability

8. Toughtness

9. Machinability 

10. Resilience

11. Creep

12. Fatigue

13. Hardness .