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Title: Development of a pseudo phased array technique using EMATs for DM weld testing

Ultrasonic inspection of dissimilar metal (DM) welds in piping with cast austenitic stainless steel (CASS) has been an area ongoing research for many years given its prevalence in the petrochemical and nuclear industries. A typical inspection strategy for pipe welds is to use an ultrasonic phased array system to scan the weld from a sensor located on the outer surface of the pipe. These inspection systems generally refract either longitudinal or shear vertical (SV) waves at varying angles to inspect the weld radially. In DM welds, however, the welding process can produce a columnar grain structure in the CASS material in a specific orientation. This columnar grain structure can skew ultrasonic waves away from their intended path, especially for SV and longitudinal wave modes. Studies have shown that inspection using the shear horizontal (SH) wave mode significantly reduces the effect of skewing. Electromagnetic acoustic transducers (EMATs) are known to be effective for producing SH waves in field settings. This paper presents an inspection strategy that seeks to reproduce the scanning and imaging capabilities of a commercial phase array system using EMATs. A custom-built EMAT was used to collect data at multiple propagation angles, and a processing strategy known as themore » synthetic aperture focusing technique (SAFT) was used to combine the data to produce an image. Results are shown using this pseudo phased array technique to inspect samples with a DM weld and artificial defects, demonstrating the potential of this approach in a laboratory setting. Recommendations for future work to transition the technique to the field are also provided.« less
Authors:
;  [1] ; ; ; ;  [2]
  1. Southwest Research Institute, Sensor Systems and Nondestructive Technology Department, 6220 Culebra Road, San Antonio, TX 78238-5166 (United States)
  2. IHI Corporation, Nuclear Power Operations, Yokohama Engineering Center, 1, Shin-Nakahara-cho, Isogo-ku, Yokohama 235-8501 (Japan)
Publication Date:
OSTI Identifier:
22391197
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1650; Journal Issue: 1; Conference: 41. Annual Review of Progress in Quantitative Nondestructive Evaluation, Boise, ID (United States), 20-25 Jul 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AUSTENITIC STEELS; DEFECTS; IMAGES; MATERIALS TESTING; METALS; SENSORS; SHEAR; SURFACES; TRANSDUCERS; ULTRASONIC WAVES; WELDED JOINTS; WELDING