Automatic charting of ultrasonically detected flaws in bar

The problems associated with ultrasonic testing of bar and billets are described and the advantages and disadvantages of an imniersion technique considered. A semi-immersion system employing probe scanning which has been successfully used on steel bar is described. The need for a physical picture of the location of defects and the limitations of the conventional oscilloscope display in this respect are pointed out. Details are given of an electronic unit for coupling an ultrasonic test set to a standard 4-channel pen recorder, to obtain analogue representation of the depth, severity and longitudinal positions of internal defects. Typical records and results achieved in practice are presented.