An Ultrasonic Evaluation Method for Grain Size Eliminating the Effect of Water Acoustic Distance

Abstract

The invention discloses a grain size ultrasonic evaluation method without the influence of underwater sound distance. The method comprises the following steps: a calibrated metal testing block is subjected to data acquisition, an original grain size evaluation model structure without the influence of underwater sound distance is primarily analyzed and determined, a pivot element of the dimensionality-reduction combination of all variables in the original evaluation model is calculated by a PCA (Principal Component Analysis) method, an implicit grain size evaluation model without the influence of underwater sound distance is established through parameters of each pivot element regression estimation model, and a tested block which is not subjected to model calculation is subjected to grain size evaluation. The method can reduce the error of the average grain size evaluation system and is mainly used for measuring the metal testing block with the average grain size of 105.57mu m by use of a metallographic phase method, the model evaluation result is 106.74mu m and the error is only 1.1%; and the provided method can inhibit the adverse effect of the underwater sound distance adjusting precision on the grain size evaluation and can improve the metal grain size nondestructive evaluation reliability.

Description

technical field [0001] The invention relates to the technical field of metal average grain size measurement, in particular to an ultrasonic evaluation method for grain size that eliminates the influence of water acoustic distance. Background technique [0002] Grain size is an important parameter to characterize the microscopic properties of metal materials, which affects the mechanical properties of materials such as fatigue strength, yield strength, toughness and plasticity, creep resistance and fatigue expansion resistance. Therefore, it is of great significance to accurately measure the grain size of metal materials for the study of their mechanical properties. There are two methods for measuring the grain size of metal materials: destructive and nondestructive. Destructive methods such as metallography have the advantages of intuitive results and high detection accuracy, but they need to destroy the material, and the analysis procedures are cumbersome and the detection ...

AI Technical Summary

Problems solved by technology

However, accurate detection of the attenuation coefficient in engineering practice will be constrained by a series of harsh experimental conditions

For example, under the conditions of different water sound distances, the attenuation coefficient detected for the same material is not a constant value, and the existing detection models do not consider the water sound distance as an influencing factor, and it takes a lot of time to adjust the water sound distance in actual detection. Focus the sound beam in the middle of the measured object, and the adjustment accuracy is difficult to guarantee

Images