Guideline for the Determination of the Scanning Grid for the Automated Ultrasonic Testing of Large Forgings

The quality requirements for large forgings, especially those used in the manufacture of power generation machinery, i.e., for tubine and generator rotors, have increased continuously over the past years. A consequence is the growing number of forgings, which have to be subjected to automated non-destructive ultrasonic testing. When going from manual to automated ultrasonic testing it requires the specification of many parameters, including the sampling distance, i.e. the distance between adjacent scanning points in the scan direction and the index direction, i.e., the distance between adjacent scan-lines in index direction. Scan step and index step define the scanning grid.