Image de-noising method for coarse austenite stainless steel welding line ultrasonic detection

Abstract

The invention discloses an image de-noising method for coarse austenite stainless steel welding line ultrasonic detection, and belongs to the field of ultrasonic nondestructive detection. The method comprises the following steps: at first, detecting a welding line by an ultrasonic detection system, which comprises a flaw detector, a probe, and a scanning apparatus, to obtain an ultrasonic image, outputting A scanning signal data that forms the ultrasonic image; then reconstructing the ultrasonic image through a signal time shifting and amplitude addition treatment; finally extracting the phase information of A scanning signal through Hilbert transform, establishing weight factors representing the phase position distribution of each point of the ultrasonic image on the basis of standard deviation of phase position, and amplifying the contribution of signal phase position distribution on flaw echo amplitude in the ultrasonic image to inhibit the noise amplitude of structure with randomly distributed phase positions. The provided method can be used to detect the ultrasonic defects of a coarse grain material and has a good application and promotion value.

Description

technical field [0001] The invention relates to an image noise reduction method for ultrasonic detection of coarse-grained austenitic stainless steel welds, which belongs to the field of ultrasonic non-destructive testing. Background technique [0002] Coarse-grained austenitic stainless steel weld materials are widely used in nuclear power and chemical industries, and their safety has attracted much attention. Ultrasonic testing (UT) has the advantages of good directionality, high energy, strong penetrating power, harmless to the human body, can locate and quantify defects in the medium, and is sensitive to area-type defects that are more harmful, so it is commonly used Weld inspection method. However, the interaction between the coarse elastic anisotropic grains in the austenitic stainless steel weld and the ultrasonic wave will lead to strong structural noise in the ultrasonic signal / image, resulting in missed detection or misjudgment of defects. [0003] In recent year...

AI Technical Summary

Problems solved by technology

Aiming at the problems of strong structural noise and low signal-to-noise ratio of defects in ultrasonic images caused by the austenitic stainless steel weld structure, based on the phase standard deviation of the A-scan signal data that constitutes the ultrasonic image, a weighting factor for characterizing the phase distribution is established to amplify the phase The contribution of the distribution to the amplitude of the defect echo in the image effectively suppresses the amplitude of the structural noise, significantly enhances the defect signal-to-noise ratio of the ultrasonic image of the coarse-grained austenite weld, and provides a solution for the ultrasonic defect detection of coarse-grained materials

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