Data-Processing for Ultrasonic Phased Array of Austenitic Stainless Steel Based on Wavelet Transform

In order to suppress the large number scattering signal echoes caused by the coarse grain structure which is tend to cover up the defect signal, resulting in the defect misjudgment in the detection of austenitic stainless steel material by ultrasonic phased array, the wavelet transform was applied to deal with the experimental data. By introducing the theory of wavelet transform and based on the study of ultrasonic testing characteristics of austenitic stainless steel welds, ultrasonic phased array testing were performed in an austenitic stainless steel welds test block, a real-time S-scan detection image was chosen for quantitative analysis from an UT acquisition system. The experimental results show that the wavelet transform can enhance the signal-to-noise ratio of the austenitic stainless steel ultrasonic phased array inspection effectively and help identify the location of defects. The researches demonstrate that this method achieves the defect measurement for the 90 mm thick of austenitic stainless steels.