TABLE OF CONTENTS The choice of materials is a major determinant for the successful functioning and the feasible, low-cost manufacture of any product. The design engineer must tread a course (which is often a narrow one) between functional requirements on one hand and cost considerations on the other. In some cases, there will be a real conflict between function and cost in the selection of a material. In other cases, happily, the choice is easy: There is a particular material that does the job functionally and which minimizes the cost of production. It is the purpose of this section of the handbook to provide information about the properties, relative costs, and fabricability of materials so as to aid the designer in making such favorable choices.
There is a real need for economy in materials costs because, for most products, these costs account for a major portion of the total: 50 percent is a common order-of-magnitude percentage. However, the objective is not necessarily minimum materials cost but minimum overall cost, including the initial price of the material, the cost of processing and assembling it with other materials into a product, the cost of guaranteeing the durability of the product and servicing it, etc. Thus, in the long run, the lowest-cost material may not be the material with the lowest price tag.
The designer today is provided with a vast array of metallic and nonmetallic...
