Mechanized scanning, display and recording ultrasonic weld inspection

Abstract

A scanning mechanism for oscillating a watercoupled ultrasonic transducer, over the surface of a part containing a strip weld and, positioning the ultrasonic transducer along orthogonal paths of travel (one parallel to and the other orthogonal to the strip weld) is disclosed. Position sensors forming part of the scanning mechanism continuously provide signals relating to the orthogonal and oscillatory position of the transducer. An ultrasonic beam emitted by the transducer enters the part and is reflected back and forth between the surfaces of the part, through the weld. Ultrasonic specular reflections (flaw echoes) created by flaws or faults in the weld travel back to the transducer. The 'flaw echo' presence and position signals are applied to a monitor subsystem that simultaneously displays the position of the origin of flaw echoes, (and thus flaws), in two planes--one plane lying parallel to the reflecting surfaces of the part, and the other lying orthogonal to the reflecting surfaces and parallel to the strip weld. Preferably, the flaw displays are shaded in accordance with the magnitude of the received flaw echo signals. Further, a video recorder records the data being displayed for subsequent redisplay and analysis. The axis of oscillation of the transducer may coincide with the point where the ultrasonic beam enters the part, or it may lie on either side of the entry point. As an alternative arrangement, two transducers, one for transmission and the other for reception, are used to sense specular reflections that do not return to the transmitting transducer.