Ultrasonic Evaluation of Two Dissimilar Metal Weld Overlay Specimens

Crawford, Susan L. ; Cinson, Anthony D. ; Prowant, Matthew S. ; Moran, Traci L. ; Anderson, Michael T.

关键词: ALLOYS;    DEFECTS;    DETECTION;    EVALUATION;    PROBES;    SIZE;    THERMAL FATIGUE;    ULTRASONIC WAVES;    WAVELENGTHS Ultrasonic Evaluation;    Dissimilar Metal Weld;    Weld Overlay;    Phased Array;   

DOI  :  10.2172/1049665
RP-ID  :  PNNL-21502
PID  :  OSTI ID: 1049665
Others  :  Other: 401001060
Others  :  TRN: US201218%%584

学科分类：材料科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Two dissimilar metal weld (DMW) pipe-to-nozzle specimens were implanted with thermal fatigue cracks in the 13% to 90% through-wall depth range. The specimens were ultrasonically evaluated with phased-array probes having center frequencies of 0.8, 1.0, 1.5, and 2.0 megahertz (MHz). An Alloy 82/182 weld overlay (WOL) was applied and the specimens were ultrasonically re-evaluated for flaw detection and characterization. The Post-WOL flaw depths were approximately 10% to 56% through-wall. This study has shown the effectiveness of ultrasonic examinations of Alloy 82/182 overlaid DMW specimens. Phased-array probes with center frequency in the 0.8- to 1.0-MHz range provide a strong coherent signal but the greater ultrasonic wavelength and larger beam spot size prevent the reliable detection of small flaws. These small flaws had nominal through-wall depths of less than 15% and length in the 50-60 mm (2-2.4 in.) range. Flaws in the 19% and greater through-wall depth range were readily detected with all four probes. At the higher frequencies, the reflected signals are less coherent but still provide adequate signal for flaw detection and characterization. A single inspection at 2.0 MHz could provide adequate detection and sizing information but a supplemental inspection at 1.0 or 1.5 MHz is recommended.