ABSTRACT Brazing is a common joining technique employed in industry to assemble sheet metal components. A metal filler wire is melted, wetting the substrate surfaces, after which it solidifies, producing a strong bond between the base material sheets. As in all joining techniques, process and material variations can lead to imperfections in brazed joints. The primary brazing imperfections studied in this investigation are lack of adhesion, porosity and inclusions in the filler material, melting of the base metal, as well as unwanted deviations in braze geometry. Several non-destructive evaluation techniques can detect the overall presence of these imperfections by comparing the joint to an ideal sample. These approaches, however, do not achieve the desired precision in quantification of the individual imperfection types, and necessitate high reproducibility in braze joint geometry. The primary difficulty in quantifying the individual imperfections is that the size and shape of both the filler and substrate materials are not known sufficiently well prior to inspection. To overcome this difficulty, ultrasonic inspection using the full matrix data acquisition method with post processing has been utilized to both detect and correct for the top braze surface in imaging the above-mentioned internal imperfections.
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