Pulse-inversion chirp-coded weld harmonic imaging (PI-CWHI) of friction stir welded butt-joint KU Leuven
The microscopic size and the closed characteristics of zigzag line defects at the root of friction stir welded joints frequently result in a detection inability by off-the-shelf ultrasonic weld inspection techniques. To overcome this problem, we take advantage of a non-linear ultrasonic approach by employing a slanted contact pitch-catch mode scanning using chirp-coded excitation with subsequent pulse-inversion analysis. We validated that the ...