As ceramic tabs have been increasingly used in welding constructions in recent years, they result in closed distribution of defects. As that result, the conventional ultrasonic angle beam testing has been anxious about the reliability of detection of weld defects. We had already submitted the applicable ultrasonic testing technique based on the artificial defects. This paper describes the reliability of evaluation on the natural defects using the conventional maximum echo height sizing technique and tip echo technique. In addition to the advanced tip echo technique, the reliability of evaluation of defect sizing has been remarkable progress.
