CN-121978134-A - Nondestructive detection method for internal structural defects of refractory material based on radar scanning

CN121978134ACN 121978134 ACN121978134 ACN 121978134ACN-121978134-A

Abstract

The invention belongs to the technical field of nondestructive detection of refractory material products, and discloses a radar scanning-based nondestructive detection method for defects of internal structures of refractory materials, which aims at special refractory material products such as fused casting products with higher density, sintered products with higher volume density and the like, a time slice view capable of randomly adjusting the observation thickness is formed by combining linear scanning or regional scanning with linear waveforms, two-dimensional maps and migration views, identification and judgment of the types, sizes and positions of the defects in the refractory material products are performed by integrating all imaging characteristics and data, a multidimensional data analysis system is formed, and quantitative analysis of internal defects such as shrinkage porosity, closed gas holes and the like of the refractory materials is realized; compared with the conventional detection means such as infrared rays and X rays, the method is simpler, more convenient and safer, improves the accuracy and comprehensiveness of identifying the defects of the internal structure, provides a reliable nondestructive detection means for quality control of refractory material products, and has definite industrial application value.

Inventors

XU DI
FU QIQI
ZHANG LIXIN
SUN MAOSHENG
ZHAO QINGBIN
GUO HEYI
QU XIAORUI
LI WANWAN

Assignees

中钢洛耐科技股份有限公司
中国核电工程有限公司

Dates

Publication Date: 20260505
Application Date: 20260401

Claims (9)

1. A radar scanning-based nondestructive detection method for internal structural defects of refractory materials is characterized by comprising the following steps: step one, line layout Determining radar areas and measuring lines of the refractory material product blank according to the type and the size of the refractory material product blank; step two, detection preparation Setting key parameters of a radar system, and matching refractory material products with different sizes and materials; Step three, linear scanning or regional scanning is carried out, and data acquisition is carried out Performing linear scanning or regional scanning on the refractory material product blank, transmitting electromagnetic waves to a radar area and a measuring line by using a step frequency continuous wave radar, and collecting electromagnetic wave echo signals reflected by the radar area and the measuring line of the refractory material product blank; step four, obtaining a linear waveform, a two-dimensional map and a migration view Synthesizing an A-scan image of the radar according to the electromagnetic wave echo signals, namely generating an original hyperbola, namely an A-scan signal by the antennae of the transmitter and the receiver according to the tracks of the electromagnetic waves reflected by different mediums; When the receiver antenna moves, a plurality of A-scan signals are collected along a scanning path, and the A-scan signals are overlapped along the advancing direction to generate a two-dimensional map; Collecting an A-scan signal and a two-dimensional map, and adding colors to structural features according to the amplitude of the A-scan signal and the advancing logic in the two-dimensional map to generate a migration view; Fifth, map processing After data acquisition of all the survey lines is completed, combining and superposing migration views at corresponding positions on the refractory material product blank according to the survey line sequence to obtain a total view of the internal structure of the blank, and observing according to different thickness slices of the blank corresponding to the propagation time to form a time slice view; sixth, pattern recognition, multi-view comprehensive analysis and defect recognition After the regional scanning is finished, the time slice view is browsed, the image is confirmed to have no clutter interference, and the position of a blank body with an abnormal signal locally is further judged; step seven, data processing and defect quantitative calculation After the linear scanning is finished, firstly, judging the position of an abnormal signal corresponding to a blank by combining the two-dimensional map and the migration view, and then analyzing and calculating the abnormal signal by combining the peak intensity corresponding to the linear waveform of the abnormal signal, the hyperbolic period corresponding to the interface signal in the two-dimensional map and the coordinates corresponding to the imaging boundary of the abnormal signal in the migration view.
2. The radar scanning-based nondestructive detection method for the internal structural defects of the refractory material is characterized in that in the second step, the modulation frequency range of a radar system is 400-6000 MHz, and the modulation frequency range is adjusted according to the thickness and precision requirements of a refractory material product blank to be detected.
3. The nondestructive detection method for the internal structural defects of the refractory material based on radar scanning of claim 1 is characterized in that the antenna type of the radar system in the second step is a step frequency continuous wave radar antenna, and the calculation formula of the step frequency is as follows: rmax is the target distance, and the thickness of a blank to be measured is generally taken; c, taking 3e 8 as the light speed in vacuum; Epsilon r dielectric constant; Δf, step frequency; The proper stepping frequency is calculated by the formula, and the missed judgment or the misjudgment caused by the improper frequency is avoided.
4. The method for nondestructive detection of internal structural defects of refractory materials based on radar scanning of claim 1, wherein in the second step, the sampling interval of a radar system is that the surface of a blank to be detected is scanned every 50mm or 100 mm.
5. The method for nondestructive detection of internal structural defects of refractory materials based on radar scanning of claim 1, wherein the third linear scanning is performed in any direction of a refractory material product blank to be detected, namely, in the X-axis or Y-axis direction, so as to obtain linear scanning data.
6. The method for nondestructive detection of internal structural defects of refractory materials based on radar scanning of claim 1, wherein the third step of regional scanning is to scan for multiple times along the horizontal direction and the vertical direction of a refractory material product blank to be detected, and two-dimensional plane scanning is performed according to preset fixed intervals of 50mm multiplied by 50mm or 100mm multiplied by 100mm, so as to obtain regional scanning data.
7. The radar scanning-based nondestructive detection method for the defects of the internal structure of the refractory material is characterized in that in the sixth step, the main defects of the internal structure of a refractory material product are shrinkage porosity and closed pores, the identification basis of the shrinkage porosity defects is that strong reflection signals with discontinuous same phase axes, staggered breakage and density appear in a two-dimensional map, the identification basis of the closed pores is that regular crescent hyperbolic waveforms appear in the two-dimensional map, and the three vibration phases are obvious.
8. The radar scanning-based nondestructive detection method for the defects of the internal structure of the refractory material is characterized in that in the seventh step, the shrinkage cavity area S is calculated by identifying the boundary range of an abnormal reflection area in a migration view, determining the range [ X1, X2] of the abnormal area in the X-axis direction and the range [ Y1, Y2] of the abnormal area in the Y-axis direction, introducing the migration view into image processing software, drawing a closed contour along the boundary of the abnormal area, calculating the area enclosed by the closed contour, and converting the area into an actual area according to an image scale; the calculation formula of the shrinkage area S is as follows: wherein I (I, j) is a defect indication function after binarization, and Δx and Δy are actual sizes corresponding to pixel points.
9. The method for nondestructive detection of internal structural defects of refractory materials based on radar scanning according to claim 1 is characterized in that in the seventh step, the closed gas hole is compared with a standard sample through peak intensity in a linear waveform, and the diameter is estimated by combining hyperbolic cycle, wherein the diameter D of the closed gas hole is calculated by the following formula: where v is the propagation velocity of electromagnetic waves in the refractory material and Δt is the hyperbolic cycle. The electromagnetic wave propagation velocity v is calculated by the following formula: wherein c is the speed of light in vacuum, ε is the relative permittivity of the refractory material.

Description

Nondestructive detection method for internal structural defects of refractory material based on radar scanning Technical Field The invention belongs to the technical field of nondestructive detection of refractory material products, and particularly relates to a radar scanning-based nondestructive detection method for internal structural defects of a refractory material. Background Conventional methods for detecting the internal structure of the refractory material are classified into X-ray detection, industrial CT and ultrasonic detection, and the limitations of the methods are obvious, and the problems of limited penetration capacity, limited sample size, low accuracy and the like exist. In particular, aiming at partial special materials, such as fused cast products with higher density and sintered products with higher volume density, the limitations of the conventional detection means are obvious, for example, X-rays only can penetrate through some green bricks with lower conventional volume density, the green bricks with higher density cannot be penetrated due to attenuation, the X-rays cannot penetrate through the thickness of the green bricks when the fused cast chrome corundum refractory bricks are detected, no imaging can be referred, industrial CT is used as the conventional detection means with highest precision, the sample preparation is required, the limitation of the detection volume is strict, only the sample with smaller size can be detected, the penetrability of ultrasonic detection is strong, the accuracy of the result is low, and the detection of infrared rays is only qualitative judgment and the accuracy is poor. Under certain severe service conditions, the internal structure of a green body of a special refractory material product has extremely high requirements, and the conventional detection method cannot provide effective judgment. Ground Penetrating Radar (GPR) technology is widely applied to geological exploration, utilizes the reflection principle of electromagnetic waves, when waves propagate in a medium, the waves are partially reflected when the dielectric constant is changed, a unique hyperbolic structure is formed, and the position, shape and property of a target can be deduced by analyzing travel time, amplitude and waveform characteristics of the reflected waves, so that the method is a nondestructive detection method. In the prior art, although the GPR technology has been applied to numerous fields such as civil engineering, geotechnical engineering and road nondestructive testing, the GPR technology has been applied to a few fields of refractory materials, and the patent literature (non-destructive testing method of refractory parts) (EP 3194940B 1) relates to a radar (electromagnetic wave) detection method, and only proposes a detection method for a fused cast refractory brick made of a specific material, but the identification and processing of imaging are not perfect, and the system application and the imaging analysis method are lacking. The refractory material product has various internal defect types, including shrinkage porosity, independent closed pores and the like, the defect size and position have obvious influence on the product quality, the medium is only air and the material, the imaging is complex, the detection image mainly still takes manual analysis and identification as the main part, the subjectivity is very strong, and the error judgment and the misjudgment phenomenon of the detection image are caused to a certain extent due to different experiences of technicians, so that the detection accuracy and the working efficiency of the ground penetrating radar are reduced. Therefore, for refractory products that cannot be detected by conventional detection means, there is a need for a nondestructive detection method that can quantitatively analyze and determine the type, size and position of defects inside the refractory material, so as to ensure the reliability and service life of the refractory product in a specific working environment. Disclosure of Invention The invention aims to solve the technical problems, and provides a radar scanning-based nondestructive detection method for internal structural defects of a refractory material, which combines linear waveforms, two-dimensional maps and migration views in nondestructive detection of internal structural defects of a refractory material product through radar linear scanning or regional scanning to form a time slice view with randomly adjustable observation thickness, and integrates all imaging characteristics and data to carry out identification and judgment on the types, sizes and positions of the defects in the refractory material product, so that a multidimensional data analysis system is formed, and the accuracy and the comprehensiveness of defect identification are improved. The technical scheme adopted by the invention is that the nondestructive detection method for the internal structural defects