ABSTRACT
The use of specifications is voluntary in the United States. However, a purchase order and contract for procurement make them subject to the laws of business contracts, and they must meet these requirements. Fastener materials are selected either by the fastener manufacturer to conform to product requirements or by a customer to meet the needs of the environment to which the fastener will be subjected. The purpose of a bolt and nut is to provide clamping force, and when you purchase a bolt you are, in effect, buying clamping force. The nut, by its design and application, enables you to achieve that clamping force. The selection of materials for bolts and nuts is based on maximum strength, high ductility, and high notch strength. Other choices are based on the environmental aspects of bolt and nut applications, and these are discussed here in separate categories.
