Appendix VIII qualification of manual phased array UT for piping

Abstract

Zetec personnel recently completed an Appendix VIII qualification of an encoded, manually-driven phased array ultrasonic testing (UT) procedure for flaw detection and length sizing in austenitic and ferritic piping welds using the portable OmniScan phased array instrument. The qualified procedure is the result of a joint Zetec/EPRI collaborative effort to qualify manual phased array techniques for application to homogeneous pipe weld examinations. The Zetec/EPRI manual phased array procedure is based on a similar approach previously qualified by EPRI using an automated phased array system. The phased array approach uses 1.5 MHz 2D array probes that enable acoustic beam steering, skewing, and focusing. The qualified procedure uses three separate probes (two looking circumferentially and one looking axially). The focal laws that generate the various beams are created using the stand alone Zetec Advanced Phased Array Calculator. Each probe is scanned parallel to the weld using a rapid, two-stroke line scan on each side of the weld. The axial position of the probes is determined from the wall thickness and the weld crown width. The encoded data is stored and subsequently analysed using the TomoView analysis software. EPRI is working with utility advisors and vendors to move phased array technology into commercial availability based on the success of the recent manual phased array ultrasonic Appendix VIII qualification for piping.