Main Factors to be Considered when Selecting Material

The main factors to be considered when selecting a material to meet some specific requirement are:

• Fitness of use,
• Formability,
• Availability, and
• Cost.

To assess the fitness of use, it is necessary to analyze the component function and determine the minimum property requirements (strength, toughness, etc.) required of a material. For any particular application, not all properties are of equal importance, for example creep resistance is of extreme importance for gas turbine disc and blade materials but of no consequence for, say, the transmission shaft of a small car, whereas fatigue resistance would be of equal importance in both cases.

Formability is an important characteristic, as this will affect the production methods to be used and costs of manufacture.

It may seem a fairly obvious point but before selecting a material it is necessary to know whether the chosen material is readily available in the quantities required.

Cost is of vital importance, as the final article must be produced at an acceptable cost if it is to be marketable. The fina1 cost will be based on both the material cost and the costs of processing.