Differences in defect indications of three artificially produced defects in ultrasonic inspection

Different types of artificial defects are used for qualification of ultrasonic inspection procedures, equipment and personnel for in-service inspections of nuclear components. To reliably evaluate the performance of an inspection, the defects have to be representative enough compared to the real service-induced defects. Fatigue cracks can nowadays be produced artificially as thermal fatigue or mechanical fatigue cracks. Thermal fatigue crack production is very well controlled in matter of size and opening and those cracks are very realistic option compared to the real service-induced defects. Mechanical fatigue crack production is a well-known and widely used method and can be used to produce very realistic cracks as well. Ultrasonic indications are highly dependent on defect characteristics like roughness, crack opening, tilt and branching. This work studies the influence of different reflector properties on defect indications. Two different types of artificial defects from different manufactures are inspected with conventional ultrasonic (UT), phased array (PA) and scanning acoustic microscope (SAM) techniques. The aim of the study is to get a wider perspective on the differences in similar type of defects from different manufacturers.