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2011
Conference Paper
Titel
SAFT ultrasonic imaging and sizing of stress corrosion cracks in the heat-affected zone of welded austenitic pressurized components
Abstract
In this contribution, we address the detection and the sizing of stress corrosion cracks occurring in the heat-affected zones of welds in austenitic stainless steels from ultrasonic inspection data. In order to improve the defect signal-to-noise ratio, particularly for the crack-tip echoes, we have applied the Synthetic Aperture Focusing Technique (SAFT). Three welded specimens of austenitic stainless steel have been examined, where stress corrosion cracks with different depth had been artificially introduced. Ultrasonic measurements to acquire Bscan data were conducted using conventional inspection set-ups with various angle beam transducers. The sizing of the cracks has been performed on the basis of the SAFT reconstructed images evaluating the angle mirror and the crack-tip echoes. The determined crack lengths show excellent agreement with the actual flaw sizes obtained from macro-graph images.