CN-122016934-A - Nondestructive testing method and device for inclusions in titanium alloy bar

CN122016934ACN 122016934 ACN122016934 ACN 122016934ACN-122016934-A

Abstract

The invention relates to the technical field of ultrasonic detection, in particular to a nondestructive detection method and device for inclusions in a titanium alloy bar. The method comprises the steps of synchronously obtaining ultrasonic A-scan signals before and after thermal imaging and thermal excitation at multiple moments through applying thermal pulse excitation, calculating a delay cooling factor based on time sequence change of pixel temperature, determining the existence rate of hot spots by combining spatial distribution of the delay cooling factor in a multidirectional adjacent area, screening a thermal anomaly area, determining a peak redundancy coefficient by utilizing time sequence fluctuation of ultrasonic signal amplitude in the area, analyzing the A-scan waveforms before and after thermal excitation through window sliding cross correlation to obtain distortion degrees, and fusing the distortion degrees to obtain ultrasonic anomaly degrees, thereby judging whether inclusions exist. The method effectively avoids ultrasonic scattering noise caused by the coarse crystal structure of the titanium alloy, and improves the reliability of detecting the tiny inclusions.

Inventors

AN ZHENYU
CHEN XIAOLAN
WANG ZIHENG

Assignees

宝鸡市启辰新材料科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. A nondestructive testing method for inclusions in a titanium alloy bar, which is characterized by comprising the following steps: Applying thermal pulse excitation to the bar, acquiring thermal imaging at imaging sampling time after thermal excitation and signal amplitude of reflective ultrasonic A-scan waveform at ultrasonic sampling time before and after thermal excitation, and determining a temperature value of a position corresponding to each pixel point in thermal imaging; Determining a delay cooling factor according to the time sequence change of the temperature value of each pixel point at different imaging sampling moments after thermal excitation, and determining the existence rate of hot spots of the pixel points in thermal imaging according to the change of the delay cooling factors of the circle centers and other pixel points in different directions in a preset radius area with the circle centers of different pixel points as circle centers; In the thermal anomaly area, combining the distribution fluctuation of the signal amplitude of the pixel point at different ultrasonic sampling moments, determining a peak redundancy coefficient, performing window sliding cross-correlation analysis on the A-scan waveforms before and after thermal excitation, and determining the distortion degree of the A-scan waveform; whether the thermally abnormal region is contaminated with an anomaly is determined based on the degree of ultrasonic anomaly.
2. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 1, wherein the determining the delay cooling factor according to the time sequence change of the temperature value of each pixel point at different imaging sampling moments after thermal excitation comprises: determining a temperature value peak value after thermal excitation of each pixel point and a time interval corresponding to temperature half-decay; and (5) carrying out standardization treatment on the time interval to obtain the delay cooling factor.
3. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 1, wherein the determining the existence rate of hot spots of the pixels in thermal imaging according to the change of the delay cooling factors of the circle centers and other pixels in different directions comprises: acquiring delay cooling factors of pixel points on the radius length from the circle center to the outline in each preset direction, and sequencing according to the sequence from the circle center to the outline to obtain a cooling sequence; Calculating the numerical difference of the delay cooling factors of the circle center pixel point and other pixel points of the cooling sequence, and determining the heat diffusion difference degree of the circle center pixel point corresponding to the preset direction; and performing dispersion analysis on the heat diffusion differences in all preset directions to obtain the existence rate of the hot spots.
4. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 3, wherein the performing a dispersion analysis on the differences of thermal diffusion in all preset directions to obtain the existence rate of hot spots comprises: Calculating standard deviation normalization values of the heat diffusion difference degrees in all preset directions, and using a difference value between a constant 1 and the standard deviation normalization values as a direction analysis index; taking normalized values of the thermal diffusion difference mean values of all preset directions as numerical analysis indexes; And calculating the average value of the numerical analysis index and the direction analysis index to obtain the hot spot existence rate.
5. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 1, wherein the screening of the thermally abnormal region according to the presence rate of hot spots comprises: taking the pixel point with the hot spot existence rate larger than a preset existence threshold value as a suspected pixel point; And determining the number of other suspected pixel points in the eight neighborhood range of the suspected pixel points, and taking the suspected pixel points with the number larger than the preset number as inclusion abnormal pixel points, wherein the inclusion abnormal pixel points form a thermal abnormal region.
6. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 1, wherein the step of determining the peak redundancy coefficient by combining the distribution fluctuation of the signal amplitudes of the pixel points at different ultrasonic sampling moments comprises the steps of: calculating the average value of the peak values and the maximum values of the signal amplitudes of all the pixel points in the thermal anomaly area, and carrying out standardized processing on the average value of the peak values and the maximum values to obtain the peak value amplitude characteristic value of the thermal anomaly area; calculating the peak value maximum standard deviation of the signal amplitudes of all pixel points in the thermal anomaly area, and normalizing the peak value maximum standard deviation to obtain a peak value discrete characteristic value; And merging the peak amplitude characteristic value and the peak discrete characteristic value to determine a peak redundancy coefficient.
7. The nondestructive testing method for the inclusions in the titanium alloy bar according to claim 1, wherein the window sliding cross-correlation analysis is performed between the a-scan waveforms before and after the thermal excitation to determine the distortion degree of the a-scan waveforms, and the method comprises the following steps: acquiring a pre-excitation amplitude sequence of an A-scan waveform based on windows with preset number and length at different ultrasonic sampling moments before thermal excitation; Acquiring an excited amplitude sequence of the A-scan waveform based on windows with preset number and length at different ultrasonic sampling moments after thermal excitation; Based on window sliding of different step sizes, carrying out pearson correlation analysis by combining the amplitude sequence before excitation and the amplitude sequence after excitation of each pixel point, and determining the distortion degree of the A-scan waveform of the thermal anomaly region.
8. The nondestructive testing method for inclusions in a titanium alloy bar according to claim 1, wherein the determining of the degree of ultrasonic anomalies by combining the peak redundancy factor and the a-scan waveform distortion comprises: and calculating the product value of the peak redundancy coefficient and the A-scan waveform distortion degree, and normalizing to obtain the ultrasonic abnormality degree.
9. The method for non-destructive inspection of inclusions within a titanium alloy rod according to claim 1, wherein said determining whether a thermally abnormal region is contaminated with an anomaly based on the degree of ultrasonic anomaly comprises: And determining that abnormal objects are included in the thermal abnormal area with the ultrasonic abnormal degree larger than a preset abnormal threshold value, otherwise, determining that abnormal objects are not included.
10. A nondestructive inspection device for inclusions in a titanium alloy bar, the device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the computer program, performs the steps of the method of any one of claims 1-9.

Description

Nondestructive testing method and device for inclusions in titanium alloy bar Technical Field The invention relates to the technical field of ultrasonic detection, in particular to a nondestructive detection method and device for inclusions in a titanium alloy bar. Background The internal nonmetallic inclusion (such as oxide, nitride and the like) is one of the common defects in the titanium alloy bar, and can become a crack source in the subsequent deformation or stress process, so that the bar is subjected to high-efficiency and reliable nondestructive detection before being put into use, so that the material containing the hazardous inclusion is screened and removed, and the method is an indispensable link for guaranteeing the safety of an industrial chain. In the prior art, a pulse reflection type ultrasonic detection method is generally used for determining whether impurities exist or not based on a reflection waveform, but ultrasonic waves can generate strong scattering at a crystal boundary when passing through the coarse crystal structure, so that high background structural noise is formed, tiny impurities are difficult to reliably identify, missed detection and false alarm coexist, and therefore tiny internal impurities cannot be reliably and accurately detected under the special strong structural noise background of titanium alloy. Disclosure of Invention In order to solve the technical problem that tiny internal inclusions cannot be reliably and accurately detected under the special strong structural noise background of titanium alloy in the related art, the invention provides a nondestructive testing method and device for the internal inclusions of a titanium alloy bar, and the adopted technical scheme is as follows: The invention provides a nondestructive testing method for inclusions in a titanium alloy bar, which comprises the following steps: Applying thermal pulse excitation to the bar, acquiring thermal imaging at imaging sampling time after thermal excitation and signal amplitude of reflective ultrasonic A-scan waveform at ultrasonic sampling time before and after thermal excitation, and determining a temperature value of a position corresponding to each pixel point in thermal imaging; Determining a delay cooling factor according to the time sequence change of the temperature value of each pixel point at different imaging sampling moments after thermal excitation, and determining the existence rate of hot spots of the pixel points in thermal imaging according to the change of the delay cooling factors of the circle centers and other pixel points in different directions in a preset radius area with the circle centers of different pixel points as circle centers; In the thermal anomaly area, combining the distribution fluctuation of the signal amplitude of the pixel point at different ultrasonic sampling moments, determining a peak redundancy coefficient, performing window sliding cross-correlation analysis on the A-scan waveforms before and after thermal excitation, and determining the distortion degree of the A-scan waveform; whether the thermally abnormal region is contaminated with an anomaly is determined based on the degree of ultrasonic anomaly. Further, the determining the delay cooling factor according to the time sequence change of the temperature value of each pixel point at different imaging sampling moments includes: determining a temperature value peak value after thermal excitation of each pixel point and a time interval corresponding to temperature half-decay; and (5) carrying out standardization treatment on the time interval to obtain the delay cooling factor. Further, the determining the existence rate of the hot spots of the pixel points in thermal imaging according to the change of the delay cooling factors of the circle centers and other pixel points in different directions includes: acquiring delay cooling factors of pixel points on the radius length from the circle center to the outline in each preset direction, and sequencing according to the sequence from the circle center to the outline to obtain a cooling sequence; Calculating the numerical difference of the delay cooling factors of the circle center pixel point and other pixel points of the cooling sequence, and determining the heat diffusion difference degree of the circle center pixel point corresponding to the preset direction; and performing dispersion analysis on the heat diffusion differences in all preset directions to obtain the existence rate of the hot spots. Further, performing dispersion analysis on the thermal diffusion differences in all preset directions to obtain a hot spot existence rate, including: Calculating standard deviation normalization values of the heat diffusion difference degrees in all preset directions, and using a difference value between a constant 1 and the standard deviation normalization values as a direction analysis index; taking normalized values of the thermal diffusion diff