The future of ultrasonic examination in engineering

Abstract

Ultrasonic testing is already essential in constructing and operating modern engineering plant, where it is used to detect and measure metallurgical defects which could undermine plant integrity. Safety requirements and the costs of component failure are powerful incentives to apply ultrasonics more widely, and to improve its reliability and efficiency. In particular, ultrasonics is needed to detect planar defects and to measure the defect dimensions which fracture mechanics shows to be structurally significant. The future of ultrasonics will, therefore, be linked closely with the growing use of fracture mechanics to assess defects. The unacceptable defects in a component must be at least as large as those which ultrasonics can detect and measure. At present, however, the performance of ultrasonics is poorly quantified. Consequently, further research is required into the interpretation of echoes, into the inherent limitations of ultrasonic techniques, and into the consequences of non-ideal testing conditions. Fundamental research will also improve ultrasonics for inspecting Inconel and austenitic steel welds, which present special difficulties. Improvements in equipment and procedures will extend the scope of both manual and automatic inspections. Automatic tests will increase the reliability and speed of testing, and will operate in hostile environments. In addition, holographic and other signal processing methods will aid defect diagnosis.