Novel ultrasonic testing of complex welds

Fluor and RTD have recently applied an ultrasonic testing (UT) technique that incorporates a phased array to field and shop operations. The new technique allows verification of weld integrity for difficult to access welds such as branch connection fittings and full penetration groove welds with fillet reinforcements. Verification of these types of welds is a necessity for power, oil and gas facilities, in particular, those operating under high pressure, high temperature, and corrosive environments. Historically, visual inspections of welds and radiograph testing (RT) have been used, but these methods are costly, time-consuming, and cannot match the benefits of the new UT phased array (UT-PA) method. The UT-PA technique has an arrangement of multiple piezoelectric elements that are independently controlled for developing synchronized and manageable sonic waves. The technique requires less time than conventional UT, is not hazardous as compared to RT, and allows for 100% volumetric inspection. Other advantages of UT-PA include its ease of use, increased accuracy, and development of instantaneous digital inspection records for tracking defect propagations in the future. The present work describes the application of this nondestructive examination (NDE) technique to a branched connection of an ASTM B564 outlet fitting to both an ASTM A608 modified 20Cr-32Ni-Nb statically cast header and an HP45 modified tee. An outline of the advantages for the UT-PA method is also included which explains the rationale that, in the future, will cause the welding industry to rely more on modified UT advanced imaging.