Ultrasonic Method for Testing Spot-Welds

Abstract

We developed a technique for nondestructively evaluating spot-welds based on through-transmission of Lamb waves. The nugget diameter can be evaluated by measuring the width of the zone where attenuated transmitted waves are observed. A particularly important feature of the developed technique is that spot-welds with no weld metal can be reliably distinguished from spot-welds with weld metal. We also developed a measuring system using array transducers. The measurement results using the system agree well with the nugget diameters measured by cross-sectional observation.