Recent Advances in Feature Extraction Techniques Being Developed for Ultrasonic Examination of Austenitic Stainless Steel Welds

摘要

Techniques are described which are being developed to characterize the features found during ultrasonic examination of stainless steel welds which are indicative of defects. Ultrasonic waveforms obtained from both defects and grain boundaries have similar time-domain characteristics. This phenomenon, together with variable signal attenuation and dispersion, is commonly encountered. The problem is to develop feature extraction techniques which will enable the examiner to discriminate realiably between weld defect signals and the other noise. Techniques presented use both time and frequency domain algorithms. The use of these techniques has demonstrated significantly better discrimination than conventional ultrasonic methods. (ERA citation 04:023079)