TABLE OF CONTENTS Product forms commonly subjected to ultrasonic inspection can be wrought, cast, welded, composite, or other materials. There are two main applications for nondestructive testing (NDT) in general. These are production-type tests of either raw materials and/or new components, and inspections that take place at a time when the component is in service. There is virtually an infinite list of areas where ultrasonic testing can be applied. It is, however, prudent to remember that the shape and orientation of a discontinuity does not always lend itself to ultrasonic inspection.
The application of almost any method of nondestructive testing is dependent on factors such as the nature of the material, accessibility to critical areas, component geometry, discontinuities that are sought, and cost factors. From an economic standpoint, the cost of dismantling a system for NDT plus the cost of the NDT itself has to be considered against the cost of replacement of the component or system. The amount and method of inspection necessary to ensure an acceptable product or system as well as the probability of discontinuity detection has to be evaluated. For example, it is certainly possible to scan a complete tank floor and map the corrosion ultrasonically; however, the cost of performing this may exceed the cost of replacing the tank floor. In this case, there are other less timeconsuming and therefore more economical means of accomplishing this task; in this instance, magnetic flux leakage.
A general description of some applications for UT follows.
