Phased Array Ultrasonic Evaluation Method of Grain Size

Abstract

The invention provides a phased array ultrasonic evaluation method of crystal grain size, the method includes: using the primary bottom echo and the secondary bottom echo to obtain the experimental longitudinal wave scattering attenuation coefficient; deriving the linear phased array from the Huygens principle The probe radiates the sound field, receives the average sound pressure through the probe, defines the diffraction correction coefficient of the linear phased array probe and calculates the final diffraction correction coefficient; according to the Weaver ultrasonic scattering model, the theoretical relationship between the grain size and the longitudinal wave scattering attenuation coefficient is obtained, based on the nonlinear minimum The square method uses polynomial fitting to obtain the proxy model of the grain size and the theoretical longitudinal wave scattering attenuation coefficient; the experimental longitudinal wave scattering attenuation after removing the diffraction loss is substituted into the proxy model to invert the grain size value. The invention eliminates diffraction loss interference, fuses multi-angle sound beam information, and greatly reduces relative error compared with traditional methods, and provides a feasible and reliable means for estimating the grain size of polycrystalline materials.

Description

technical field [0001] The invention belongs to the technical field of grain size evaluation, in particular to a phased array ultrasonic evaluation method of grain size. Background technique [0002] Grain size is an important factor affecting the mechanical properties of polycrystalline materials, such as yield strength, creep strength, and corrosion resistance. For example, the Hall-Petch effect shows that the hardness and yield stress of a material generally increase with decreasing grain size. However, during heat treatment, melting or machining, the actual grain size may deviate from the design value. Therefore, it is of great significance to effectively evaluate the grain size to ensure the safe service of key components. [0003] Grain size evaluation can be divided into destructive and non-destructive methods. Destructive methods are mainly metallographic and electron backscattered diffraction, but they can only detect local information, and require sophisticated ...

AI Technical Summary

Problems solved by technology

This requires consideration of not only the transmit delay for deflection or focusing, but also the receive delay for summing all received signals, which makes diffraction correction for phased-array probes more complex than conventional single-probe diffraction correction, which has not yet been implemented. There are calibration methods that can be used directly with phased array probes

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