Phased array and TOFD in lieu of RT for pre- and in-service inspections

摘要

As the restrictions in the use of industrial radiography (RT) have increased over the years, the need for alternative weld inspection methods and techniques, such as time-of-flight diffraction (TOFD) and phased array (PA), has become more evident.In this article, Norbert Trimborn, Strategic Business Leader, Advanced NDT at SGS, discusses the replacement of RT by PA and TOFD. Information is given about the inspection requirements for pre-service and in-service inspections. Based on these requirements, SGS has developed a PA inspection system for the inspection of boiler tube welds. The advantages and disadvantages of this system are discussed by giving information about general advantages, combined with an overview of the differences in the detection and sizing of different types of defect.