Phased array ultrasonic technology contribution to engineering critical assessment(eca) of economizer piping welds

摘要

Applications of phased array to evaluate the crack ligament in the counterbore region of economizer piping welds was successful implemented in the field and the PA data were used by EGA for Tee diposition. Sizing of the last significant tip is a challenge for PA techniques. A combination of three to four techniques is required and a diversity of phased array probes with different frequencies and focus depth led to a reliable ligament evaluation. PA undersized the cracks by -0.5 mm (average). Conservative EGA decision was to subtract -2 mm from the ligament reported by PA. Field inspection was reliable and very productive. EGA engineer witnessed the PAUT inspection. The sectorial scan data display was very friendly used by EGA specialist and the customer understood within minutes the dai:data display cursors readings and ligament evaluation. The disposition criterion for Tee with significant cracks was based on PAUT reliabiltiy (validation, diversity and redundancy) and EGA conservative decision. Calibration on economizer sample 9A with two known counterbore cracks contributed to a high-accuracy evaluation.