ERRORS OBSERVED IN THE ULTRASONIC DETECTION AND SIZING OF ARTIFICIAL DEFECTS IN FUSION WELDED JOINTS.

This paper details the results of two ultrasonic test programs performed on artificial defects in fusion welded joints. The results of the initial program were very poor and considerable variability, both between operators and between predicted and actual defect parameters, was observed. There was a general tendency to undersize defect lengths and heights, while an apparent trend in oversizing defect depths could have arisen due to undersizing the heights. The twelve operators involved in the second test program obtained a far greater accuracy in predictions of defect parameters. These results indicated that if a series of unknown, but different sized defects were ultrasonically inspected, then the range in the ultrasonic testing predictions would give some indication of the relative extent of the defects. These results however, are contingent on the inspectors being given sufficient information about the defect, and provided with a specified sizing procedure.