抄録
Spot-welding technique is widely used in the various fields of engineering and industries. Since the size and quality of the nugget which is melted and re-solidified part of a welding are closely related to the strength of the welded structure, it is important to estimate the diameter and mechanical property of the nugget quantitatively. In this work, an air-coupled ultrasound technique employing focused transducers has been used for non-contact measurements of a spot-welding. Transmission C-scan measurements were performed using a pair of focused transducers operating with tone burst waves at 0.4 MHz. A method for determining nugget size from the amplitude of the transmitted signal has been developed. The method has applied to the measured C-scan images to determine the nugget size of the welding.
