Full characterization of near-surface flaws with multimode straight-beam transducers

摘要

Reliable and accurate characterization as to type (cracks vs. others), location (highly stressed zone or not), and size of potential flaws in cladded pressure vessels by ultrasonic methods ensures the integrity of these structures. Vessel integrity is primarily affected by the presence of fatigue cracks in the highly stressed near- surface regions (Zones 1 and 2). While there have been some new high- and low- beam multimode transducer developments for characterizing Zone 2 (underclad) and Zone 3 (deeply buried) flaws, respectively [1,2], emphasis has recently been placed upon fully characterizing manufacturing flaws in the cladding (Zone 1) because they can initiate fatigue cracks.