Abstract
A nondestructive evaluation method for delineating weld interface of arc weld in hot rolled steel sheet for automotive structure is developed by a nonlinear ultrasonic imaging. The ultrasonic wave of 20MHz from the ultrasonic sensor sends, the received signal is amplified through the high-pass filter of 40MHz, and the image is created from the data. With the nonlinear ultrasonic technique, the higher harmonic amplitudes at weld interface appear large. The estimated weld interface close to the contour line obtained by the macro photographs. Thus, the destructive observation of the weld interface could be replaced by the nonlinear ultrasonic imaging.
