Development of Inspection Method for Pipes by Non Contact Air Coupled Ultrasonic Testing

We have developed the constant incident angle method to inspect pipes by using high power square burst wave in non contact air coupled ultrasonic testing (NAUT). We also succeeded to scan the effective guided wave propagated circumferentially in pipes. This paper describes the optimum frequency, incident angle, the selection of probes and examples of detecting image pictures with the constant incident angle focusing method using focus probe.