Crystal grain size averaging method based on polycrystalline material extraction by effective ultrasonic backscatter signal

Abstract

The invention provides a crystal grain size averaging method based on polycrystalline material extraction by an effective ultrasonic backscatter signal, which belongs to the field of ultrasonic nondestructive characterization. The method comprises the following steps: a water immersion ultrasonic scanning system having a full-waveform storage function and a water immersion ultrasonic focusing probe are employed for collecting an A scanning signal of a reference test block; then a space variance of the A scanning signal is calculated through MATLAB, and an actual measurement experiment curve isobtained; a ultrasonic backscatter theoretical model coupled with a practical detection system; finally, the actual measurement experiment curve and a ultrasonic backscatter theoretical model curve are subjected to fitting, a material space correlation function corresponding to a reference test block is solved by an iterative method is employed, and an average size of the crystal grain can be extracted, a solution scheme is provided for the average crystal grain size of the ultrasonic nondestructive characterization of a polycrystalline material, and the method has good application prospect and popularization value.

Description

technical field [0001] The invention relates to the field of ultrasonic nondestructive characterization of microstructure characteristics of polycrystalline materials, and more specifically relates to a method for extracting the average grain size of polycrystalline materials based on effective ultrasonic backscattering signals. Background technique [0002] Polycrystalline materials such as austenitic stainless steels, nickel alloys and titanium alloys are mostly used in modern industry. This type of polycrystalline material is composed of single crystal grains with different sizes, shapes, and orientations and grain boundary spacing, and has a more complex microstructure than single crystal materials. Ultrasonic waves enter the interior of the material, and their propagation becomes extremely complicated. The impact of ultrasonic scattering on ultrasonic testing is the most significant. The ability of ultrasonic flaw detection largely depends on the microstructural proper...

AI Technical Summary

Problems solved by technology

The attenuation method has high measurement accuracy, but it needs to correct parameters such as workpiece surface roughness, coupling agent, and ultrasonic beam divergence, and is greatly affected by factors such as component thickness, internal defects, and grain uniformity. It can be seen comprehensively that the current Existing detection and evaluation methods have great limitations for the non-destructive characterization of complex polycrystalline materials, especially polycrystalline metal materials in service

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