Data Fusion of Non Destructive Testing for Detection of Defects in Welding

In this paper the specimens of Aluminum 2024 with 5 millimeter in thickness are joined together by friction stir welding with travel speed of 100 mm/min and tool rotational speeds of 450, 900 and 1800 rpm and a tool were made of hot working steel, H13, firstly. Thus three kinds of welds are produced. Radiography and ultrasonic (UT) non-destructive testing (NDT) procedure were applied to characterize the presence and geometry of possible weld defects prior to mechanical destructive testing. A Echograph Model 1090 digital UT instrumentation and a 4 MHz angle beam probe (refraction angle α = 70°) was used for C-scan of UT contact testing of welded samples (transverse UT velocity 2850 m/s and signal amplification 40 dB). The detection accuracy of defects can be improved by image fusion of ultrasonic and radiography data. For this reason, the data of the two sensors are transformed into a same scale images (length, width and also depth). Pixel by pixel image fusion is used for fusion and analysis. Comparing these results with the destructed part shows that the fusion of two tests improves the results.