Sensitivity compensation method of defects in defocusing area of ultrasonic focusing probe

Abstract

The invention provides a sensitivity compensation method of defects in the defocusing area of an ultrasonic focusing probe.The sensitivity compensation method is characterized in that sensitivity compensation curves are actually measured by manufacturing compensation samples, the ultrasonic echo data of the to-be-measured samples is acquired through an ultrasonic microscope, the X, Y and Z spatial coordinates of the defects are extracted, corresponding compensation curves are selected according to actual detecting conditions, and sensitivity compensation is completed according to the depths Hdefect of the defects and the positions Hfocus of focuses.The sensitivity compensation method has the advantages that the detecting sensitivity of the defects in the defocusing area of the focusing probe is achieved; compared with AVG curves of flat probes, the method is more suitable for the focusing probe, the sensitivity compensation of the defects of the defocusing area is achieved, high precision and repeatability are achieved, the method is significant to fast defect detection and defect size representation, and misjudgment of defect size is avoided; by the sensitivity compensation, the defect size and number in materials can be statistically analyzed, and the purity of metal materials can be evaluated accurately.

Description

technical field [0001] The invention belongs to the field of ultrasonic detection, and in particular relates to a sensitivity compensation method for defects in the defocus area of ​​an ultrasonic focusing probe. Background technique [0002] The sound field emitted by the ultrasonic focusing probe has the advantages of thin sound beam, concentrated energy, high resolution and sensitivity. When the focusing probe is working, the piezoelectric chip in the probe converts electrical energy into mechanical energy through the inverse piezoelectric effect, and excites ultrasonic waves. The sound waves converge to a point through the action of the lens, which is called the focus of the probe. However, the focal point after ultrasonic focusing is not a theoretically space-free geometric point, but an approximate cylinder. The inside of the cylinder is the focusing area, and the outside of the cylinder is the defocusing area. [0003] When the focus probe is used for detection, when...

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Problems solved by technology

[0004] When performing internal defect detection on a test piece, since the depth of the internal defect is uncertain, the ideal focus position cannot be preset to ensure that all defects can be located in the fo

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