Ultrasonic Testing for Detection of IGSCC

摘要

Beginning in the fall of 1974, numerous intergranular stress-corrosion cracks (IGSCC) have been found in the heat-affected zone (HAZ) of welded Type 304 stainless steel reactor piping. As a result of these findings, a 2-year program sponsored by EPRI was initiated at Argonne National Laboratory (ANL) in 1975 to help establish the adequacy of conventional ultrasonic-testing techniques for the detection of IGSCC. This paper discusses the quantitative data describing the effect of transducer parameter variations on ultrasonic echo amplitude from a variety of artificial and natural reflectors and gives suggestions for improvements in ultrasonic in-service testing methods, including the use of focussed probes. The effect of variation in ultrasonic attenuation between HAZ and base metal, the importance of adequate reference standards, and geometric effects are also discussed, and recent efforts at ANL and other institutions to improve ultrasonic detection of cracks are reviewed. (ERA citation 05:016144)