Ultrasonic nondestructive testing method, system and device for metal castings

Abstract

The present invention relates to the technical field of ultrasonic metal detection, and in particular to an ultrasonic nondestructive flaw detection method, system and device for metal castings. The present invention first obtains the hidden damage measurement of the block area according to the abnormal conditions and values ​​of the echo duration of the block area; then divides the hidden damage area from all the block areas; obtains the echo scattering measurement of the hidden damage area according to the energy dispersion of the ultrasonic echo signal in the frequency domain of the hidden damage area; obtains the echo correlation measurement of the hidden damage area according to the correlation between the ultrasonic transmission signal and the ultrasonic echo signal in the hidden damage area; obtains the detection and identification measurement of the hidden damage area according to the echo scattering measurement and the echo correlation measurement, and finally evaluates the hidden damage type of the hidden damage area in the metal casting. The present invention improves the accuracy of hidden damage evaluation of metal castings by fully considering the characteristics of the ultrasonic echo signal reflected by the hidden damage area.

Description

Technical Field

[0001] The invention relates to the technical field of metal ultrasonic testing, and in particular to an ultrasonic nondestructive flaw detection method, system and device for metal castings. Background Art

[0002] Metal castings are metal shaped objects obtained by casting. During the production process, metal castings will produce hidden defects due to the influence of factors such as casting process. Hidden defects are difficult to observe directly through vision. Ultrasonic testing is a non-destructive testing method. Ultrasonic waves can penetrate the inside of metal castings to detect internal defects. The probe of the ultrasonic flaw detector is placed close to the surface of the metal casting, and an ultrasonic transmission signal is sent into the metal casting. After the ultrasonic transmission signal propagates inside the metal, it will reflect the ultrasonic echo signal.

[0003] Ultrasonic nondestructive testing technology can be used to detect internal defects of castings in a timely manner to improve the quality and reliability of metal casting products. The existing technology determines the defect type of metal castings by the correlation between ultrasonic emission signals and ultrasonic echo signals. When using the existing technology to detect hidden defects in metal castings, the characteristics of the ultrasonic echo signal reflected by hidden defects are not fully considered, resulting in inaccurate evaluation of hidden defects in metal castings. Summary of the invention

[0004] In order to solve the technical problem of inaccurate hidden flaw assessment of metal castings in the prior art, the object of the present invention is to provide an ultrasonic nondestructive flaw detection method, system and device for metal castings. The technical solution adopted is as follows:

[0005] An ultrasonic nondestructive testing method for metal castings, the method comprising:

[0006] Performing ultrasonic nondestructive testing on metal castings to obtain ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes echo duration and ultrasonic echo signals;

[0007] Obtaining a dark damage measure of the block area according to the abnormality and value of the echo duration of the block area; dividing the dark damage area from all the block areas according to the dark damage measure;

[0008] According to the energy dispersion of the ultrasonic echo signal of the dark damage area in the frequency domain, the echo scattering measurement of the dark damage area is obtained; according to the correlation between the ultrasonic transmission signal and the ultrasonic echo signal of the dark damage area, the echo correlation measurement of the dark damage area is obtained; according to the echo scattering measurement and the echo correlation measurement, the detection and identification measurement of the dark damage area is obtained; according to the detection and identification measurement of the dark damage area, the dark damage type of the dark damage area in the metal casting is evaluated.

[0009] Furthermore, the method for obtaining the hidden damage metric includes:

[0010] Based on the isolation forest method, the anomaly score of each block area is obtained according to the echo duration corresponding to all block areas;

[0011] The abnormal scores and the values ​​of the echo durations of the respective block regions are forwardly fused to obtain the dark damage metric of the respective block regions.

[0012] Furthermore, the method for obtaining the hidden damage area includes:

[0013] Among all the block regions of the metal casting, the block regions where the dark damage metric is greater than a preset dark damage threshold are regarded as dark damage regions.

[0014] Furthermore, the method for obtaining the echo scattering metric includes:

[0015] Based on Fourier transform, the ultrasonic echo signal corresponding to the dark injury area is converted from the time domain to the frequency domain to obtain the echo frequency domain signal corresponding to the dark injury area;

[0016] In the echo frequency domain signal corresponding to the dark damaged area, the frequency corresponding to the maximum amplitude is taken as the target frequency, and the average of all amplitudes is taken as the target amplitude; the sum of the target amplitude and the preset denominator adjustment value is calculated, and the ratio of the target frequency to the sum is calculated to obtain the echo scattering measurement of the dark damaged area.

[0017] Furthermore, the method for obtaining the echo correlation metric includes:

[0018] The Pearson coefficient of the ultrasonic emission signal and the ultrasonic echo signal of the dark damage area is calculated and normalized to obtain an echo correlation measure of the dark damage area.

[0019] Furthermore, the method for obtaining the detection and identification metric includes:

[0020] The product of the negative correlation mapping result of the echo correlation metric of the dark damage area and the echo scattering metric is calculated and normalized to obtain the detection and identification metric of the dark damage area.

[0021] Furthermore, the method for evaluating the type of hidden damage of a metal casting comprises:

[0022] The dark damage area whose detection and identification metric is greater than the preset division threshold is marked as a hole type dark damage area; the dark damage area whose detection and identification metric is not greater than the preset division threshold is marked as a crack type dark damage area.

[0023] Furthermore, the preset division threshold is 0.78.

[0024] An ultrasonic nondestructive flaw detection system for metal castings, comprising:

[0025] A data acquisition module, used for performing ultrasonic nondestructive testing on metal castings, acquiring ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes an echo duration and an ultrasonic echo signal;

[0026] A dark damage area division module is used to obtain a dark damage measurement of a block area according to an abnormality and a value of an echo duration of the block area; and divide a dark damage area from all block areas according to the dark damage measurement;

[0027] A hidden damage type assessment module is configured to obtain an echo scattering measurement of the hidden damage area according to energy dispersion of the ultrasonic echo signal corresponding to the hidden damage area in the frequency domain; obtain an echo correlation measurement of the hidden damage area according to a correlation between the ultrasonic transmission signal and the ultrasonic echo signal of the hidden damage area; obtain a detection and identification measurement of the hidden damage area according to the echo scattering measurement and the echo correlation measurement; and evaluate the hidden damage type of the hidden damage area in the metal casting according to the detection and identification measurement of the hidden damage area.

[0028] An ultrasonic nondestructive flaw detection device for metal castings comprises a memory, a processor and a computer program stored in the memory and executable on the processor. Furthermore, when the processor executes the computer program, the steps of an ultrasonic nondestructive flaw detection method for metal castings as described in any one of the above items are implemented.

[0029] The present invention has the following beneficial effects:

[0030] Considering that the echo duration of the block area with hidden defects is long and relatively abnormal, a hidden damage metric is constructed to reflect the possibility of hidden damage defects in the block area. Then, based on the hidden damage metric, the hidden damage area is divided from all the block areas, and the hidden damage area is used to preliminarily reflect the corresponding block area with hidden damage defects. The energy dispersion degree of the ultrasonic echo signal in the dark damage area in the frequency domain is quantified by the echo scattering metric; the similarity between the ultrasonic transmission signal and the ultrasonic echo signal in the dark damage area is evaluated by the echo correlation metric. The echo scattering metric and the echo correlation metric are key information for distinguishing defect types. By combining the information of the echo scattering metric and the echo correlation metric, a detection and identification metric that can accurately reflect the characteristics of the hidden damage type is obtained, thereby realizing an accurate assessment of the hidden damage type in the hidden damage area of ​​the metal casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A flowchart of an ultrasonic nondestructive testing method for metal castings provided by one embodiment of the present invention;

[0033] Figure 2 A flow chart of a method for obtaining a hidden damage metric provided by an embodiment of the present invention;

[0034] Figure 3 A structural diagram of an ultrasonic nondestructive flaw detection system for metal castings provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the ultrasonic non-destructive testing method, system and device for metal castings proposed by the present invention, its specific implementation method, structure, characteristics and effects in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0037] The following is a detailed description of a specific solution of an ultrasonic non-destructive flaw detection method, system and device for metal castings provided by the present invention in conjunction with the accompanying drawings.

[0038] The present invention provides a method, system and device for ultrasonic nondestructive testing of metal castings. Figure 1 , which shows a flow chart of an ultrasonic nondestructive testing method for metal castings provided by an embodiment of the present invention, the method comprising the following steps:

[0039] Step S1: Perform ultrasonic nondestructive testing on metal castings to obtain ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes echo duration and ultrasonic echo signals.

[0040] The present invention adopts ultrasonic nondestructive flaw detection technology, and detects metal castings block by block through a reasonably set ultrasonic flaw detector. The ultrasonic detection system can record the ultrasonic emission signal, echo duration and ultrasonic echo signal of each block area, so as to accurately judge the health status of the inside of the metal casting.

[0041] The specific implementation steps are as follows: each surface of the metal casting is divided equally by hand to obtain each block area. Before the probe of the ultrasonic flaw detector contacts the metal casting, the coupling agent is evenly applied to the contact surface of the probe. In each block area, the ultrasonic flaw detector probe is used to transmit an ultrasonic transmission signal, which propagates and reflects inside the metal casting, and finally returns the ultrasonic echo signal to the probe. For each block area, the total time from the ultrasonic detector probe transmitting the ultrasonic transmission signal to the ultrasonic echo signal receiving the ultrasonic echo signal is used as the echo duration of the block area. The ultrasonic transmission signal and ultrasonic echo signal of the probe in the block area during the ultrasonic flaw detection process are used as the ultrasonic transmission signal and ultrasonic echo signal of the block area, and the ultrasonic transmission signal in the process of ultrasonic non-destructive flaw detection of the metal casting and the echo duration and ultrasonic echo signal of each block area of ​​the metal casting are uploaded to the ultrasonic detection system. It should be noted that the same ultrasonic transmission signal is used for all block areas in the present invention.

[0042] Among them, the specific steps of reasonably setting up the ultrasonic flaw detector include: considering that the ultrasonic flaw detector includes the ultrasonic flaw detector body, probe and signal receiving module. For the ultrasonic flaw detector body: select an ultrasonic flaw detector with adjustable frequency, high sensitivity and multiple waveform functions, such as Olympus 38DL Plus, and set the equipment parameters: frequency range 0.5MHz to 15MHz, pulse repetition frequency 1Hz to 5000Hz, dynamic range greater than 100dB, measurement accuracy ±1mm. For the probe: select a suitable probe type according to the detection requirements, such as a straight probe. Set the probe parameters: frequency range 1MHz to 5MHz, excitation voltage 70V to 150V, collimation angle 0° to 70° and use a coupling agent suitable for metal surfaces to ensure good wave conduction, such as ultrasonic gel coupling agent. For the signal receiving module: select a receiver that can handle high-frequency signals and has a large dynamic range, such as Agilent33522B. Configure an amplifier with broadband gain control, such as Krohn-Hite 7500, with a gain range of 10dB to 60dB.

[0043] It should be noted that, in order to facilitate calculation, all indicator data involved in the calculation in the embodiment of the present invention are preprocessed to eliminate the dimension effect. The specific means of eliminating the dimension effect are technical means well known to those skilled in the art and are not limited here.

[0044] During the production process of metal castings, hidden defects will occur due to the influence of factors such as casting process. Hidden defects are difficult to observe directly by vision. Considering that there is a difference between the block area with hidden defects and the block area without hidden defects, that is, in the block area with hidden defects, the reflection period of ultrasonic waves inside the metal casting is increased due to the influence of internal hidden defects. The ultrasonic waves reciprocate inside the metal casting, resulting in a longer and more abnormal echo time in the block area with hidden defects.

[0045] Step S2: according to the abnormality and value of the echo duration of the block area, obtain the dark damage measurement of the block area; according to the dark damage measurement, divide the dark damage area from all the block areas.

[0046] Taking into account that the echo duration of the block area with dark damage defects is long and relatively abnormal, a dark damage metric is constructed to reflect the possibility of the existence of dark damage defects in the block area. Then, according to the dark damage metric, the dark damage area is divided from all the block areas, and the dark damage area is used to preliminarily reflect the block area corresponding to the dark damage defect.

[0047] In order to analyze the possibility of hidden defects in the block area, considering the reflection characteristics of ultrasonic waves in the block area with hidden defects inside the metal casting, a dark defect metric is constructed to reflect the possibility of hidden defects in the block area. The dark defect metric is a comprehensive indicator that combines the abnormality of the echo duration and the value size, and can more accurately reflect the possibility of hidden defects in the metal casting. Figure 2 , which shows a flow chart of a method for obtaining a hidden damage metric provided by an embodiment of the present invention. Preferably, in an embodiment of the present invention, the method for obtaining a hidden damage metric includes:

[0048] Step S201: Based on the isolation forest method, the abnormality score of each block area is obtained according to the echo duration corresponding to all the block areas.

[0049] Taking into account the reflection characteristics of ultrasound in the block areas where hidden defects exist inside metal castings and the sporadic nature of hidden defects in metal castings, that is, the echo duration corresponding to the defective area is obviously different from that corresponding to the normal area and is sporadic, the abnormal score of the block area is used to preliminarily reflect the possibility of the existence of hidden defects in the block area.

[0050] It should be noted that the isolation forest method is a tree-based anomaly detection algorithm. The isolation forest method is a prior art well known to those skilled in the art. Here, we will only briefly describe how to obtain the anomaly score of the block area based on the echo duration corresponding to all block areas based on the isolation forest method: According to the echo duration corresponding to all block areas, an isolation forest model is constructed. The echo duration of each block area is input into the model to obtain the corresponding anomaly score. The larger the anomaly score, the more abnormal the echo duration of the block area is compared with other block areas, that is, the greater the possibility of hidden defects in the block area.

[0051] Step S202: forwardly fuse the anomaly scores and echo duration values ​​of each block area to obtain the dark damage metric of each block area.

[0052] Considering that the echo duration of the block area with hidden defects is long and abnormal, a dark damage metric is constructed to reflect the possibility of the existence of hidden damage defects in the block area. The larger the dark damage metric, the greater the possibility of the existence of hidden damage defects in the block area.

[0053] It should be noted that forward fusion is an existing technology well known to those skilled in the art, and forward fusion can adopt simple product, arithmetic mean or other suitable fusion methods. In one embodiment of the present invention, the product of the abnormal score of the block area and the corresponding value of the echo duration is calculated and normalized to obtain the dark damage measurement of the block area. It should be noted that the normalization method adopted is: normalization is performed using the norm normalization function to limit the value range to between 0 and 1. Among them, normalization is a technical means well known to those skilled in the art, and the choice of normalization function can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0054] In order to analyze the block area corresponding to the dark damage defect, preferably, in one embodiment of the present invention, the method for obtaining the dark damage area includes:

[0055] In all the block areas of the metal casting, the block areas whose hidden damage measurement is greater than the preset hidden damage threshold are regarded as hidden damage areas. In one embodiment of the present invention, the preset hidden damage threshold is set based on experience. In the present invention, the preset hidden damage threshold is set to 0.67, and the implementer can set it according to the implementation scenario. It should be noted that if there is no hidden damage area in the metal casting, there is no need to evaluate the hidden damage type of the hidden damage area in the metal casting.

[0056] For the above steps, the dark damage metric is taken into account to reflect the possibility of dark damage defects in the block area. The larger the dark damage metric, the greater the possibility of dark damage defects in the block area. According to the size of the dark damage metric and the preset dark damage threshold, the dark damage area can be divided from all the block areas. The dark damage area preliminarily reflects the corresponding block area where the dark damage defect exists.

[0057] Considering that the hidden defects of metal castings are mainly divided into hole type defects and crack type defects, that is, during the solidification of molten metal, if the mold exhaust design is poor or the coating exhaust is poor, the gas may not be discharged in time, thereby forming hole defects inside the casting; due to the uneven cooling speed of various parts of the casting, internal stress will be generated. When the internal stress exceeds the tensile strength of the casting, cracking will occur, forming crack defects; since the hidden defects are hidden inside the casting, it is difficult to observe directly with the naked eye. Considering that hole defects and crack defects have different structures, the corresponding ultrasonic echo signals of the two have different characteristics. The present invention further distinguishes the hidden types of the hidden areas by analyzing the characteristics of the ultrasonic echo signals corresponding to the hidden areas.

[0058] Step S3: According to the energy dispersion of the ultrasonic echo signal in the frequency domain of the dark damage area, the echo scattering measurement of the dark damage area is obtained; according to the correlation between the ultrasonic transmission signal and the ultrasonic echo signal in the dark damage area, the echo correlation measurement of the dark damage area is obtained; according to the echo scattering measurement and the echo correlation measurement, the detection and identification measurement of the dark damage area is obtained; according to the detection and identification measurement of the dark damage area, the dark damage type of the dark damage area in the metal casting is evaluated.

[0059] The energy dispersion degree of the ultrasonic echo signal in the frequency domain of the dark damage area is quantified by the echo scattering metric; the similarity between the ultrasonic emission signal and the ultrasonic echo signal in the dark damage area is evaluated by the echo correlation metric. The echo scattering metric and the echo correlation metric are key information for distinguishing defect types. By combining the information of the echo scattering metric and the echo correlation metric, a detection and identification metric that can accurately reflect the characteristics of the dark damage type is obtained, thereby realizing an accurate assessment of the dark damage type in the dark damage area of ​​the metal casting.

[0060] Considering that hole-like hidden defects inside metal castings often have complex internal structures and a high degree of scattering, that is, the energy dispersion of ultrasonic echo signals in the frequency domain in the hidden defect area is high; while crack-like hidden defects inside metal castings often have relatively regular structures and a low degree of scattering, that is, the energy dispersion of ultrasonic echo signals in the frequency domain in the hidden defect area is low, an echo scattering metric is constructed to quantify the energy dispersion of ultrasonic echo signals in the frequency domain in the hidden defect area, which is used as a key indicator to distinguish between hole defects and crack defects. Preferably, in one embodiment of the present invention, the method for obtaining the echo scattering metric includes:

[0061] Based on Fourier transform, the ultrasonic echo signal corresponding to the dark injury area is converted from the time domain to the frequency domain to obtain the echo frequency domain signal corresponding to the dark injury area;

[0062] In the echo frequency domain signal corresponding to the dark damage area, the frequency corresponding to the maximum amplitude is taken as the target frequency, and the average of all amplitudes is taken as the target amplitude; the sum of the target amplitude and the preset denominator adjustment value is calculated, and the ratio of the target frequency to the sum is calculated to obtain the echo scattering measurement of the dark damage area. It should be noted that Fourier transform is a prior art well known to those skilled in the art and will not be described in detail here. In one embodiment of the present invention, the preset denominator adjustment value is used to prevent the denominator from being 0, and the preset denominator adjustment value can be set to 0.1, and the implementer can set it according to the implementation requirements.

[0063] For the above steps, the ultrasonic echo signal of the dark damage area is converted from the time domain to the frequency domain by using Fourier transform technology to obtain the echo frequency domain signal corresponding to the dark damage area. The ultrasonic echo signal targeted by the present invention is continuous and non-periodic, so the echo frequency domain signal corresponding to the dark damage area is discretely distributed, and the echo frequency domain signal corresponding to the dark damage area characterizes the amplitude distribution in the frequency domain and reflects the energy distribution of the ultrasonic echo signal in the frequency domain. Considering that the higher the scattering degree of the ultrasonic signal, the greater the energy loss of the received ultrasonic echo signal, the target amplitude reflects the overall energy of the ultrasonic echo signal received in the dark damage area in the frequency domain, and the lower the target amplitude value, the higher the scattering degree of the ultrasonic signal; the target frequency reflects the main frequency in the ultrasonic echo frequency domain signal, and the higher the target frequency, the more significant the scattering of the ultrasonic signal, that is, the higher the scattering degree of the ultrasonic signal; the sum of the target amplitude and the preset denominator adjustment value is calculated, and the ratio of the target frequency to the sum is calculated to obtain the echo scattering measurement of the dark damage area. The echo scattering metric comprehensively reflects the scattering degree of the ultrasonic signal. The higher the scattering degree, the higher the scattering degree of the ultrasonic signal and the more serious the energy dispersion.

[0064] In order to evaluate the similarity between the ultrasonic emission signal and the ultrasonic echo signal in the dark damage area, an echo correlation metric is constructed as a key indicator for distinguishing hole defects from crack defects. Preferably, in one embodiment of the present invention, the method for obtaining the echo correlation metric includes:

[0065] The Pearson coefficient of the ultrasonic emission signal and the ultrasonic echo signal of the dark injury area is calculated and normalized to obtain the echo correlation measurement of the dark injury area. It should be noted that the normalization method is: normalization is performed using the norm normalization function to limit the value range to between 0 and 1. Normalization is a technical means well known to those skilled in the art, and the normalization function can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0066] Regarding the above steps, considering that crack-type hidden damages often have relatively regular structures, the ultrasonic emission signal in the crack-type hidden damage area is closer to the ultrasonic echo signal; considering that hole-type hidden damages often have complex internal structures, there is a large difference between the ultrasonic emission signal and the ultrasonic echo signal in the hole-type hidden damage area; the higher the echo correlation metric, the higher the similarity between the ultrasonic emission signal and the ultrasonic echo signal, and the more likely the block area is a crack-type hidden damage area.

[0067] By integrating the information of the echo scattering metric and the echo correlation metric, a detection identification metric that can reflect the characteristics of the hidden damage type is obtained. Preferably, in one embodiment of the present invention, the method for obtaining the detection identification metric includes:

[0068] The product of the negative correlation mapping result of the echo correlation metric of the dark damage area and the echo scattering metric is calculated and normalized to obtain the detection and identification metric of the dark damage area. It should be noted that the negative correlation mapping and normalization processing are both technical means well known to those skilled in the art. The negative correlation mapping can be in the form of inverse proportion or negative exponential power, and the normalization processing can be linear normalization, etc., which are not limited here.

[0069] For the above steps, it is considered that the echo scattering metric of the hidden damage area of ​​the hole hidden damage type is often higher, while the echo scattering metric of the hidden damage area of ​​the crack hidden damage type is relatively low. It is also considered that the higher the echo correlation metric, the higher the similarity between the ultrasonic transmission signal and the ultrasonic echo signal, and the more likely the block area is a crack type hidden damage area. Combining the information of the echo scattering metric and the echo correlation metric, a detection and recognition metric that can reflect the characteristics of the hidden damage type is obtained. The larger the detection and recognition metric, the higher the scattering degree of the hidden damage area and the stronger the irregularity, and the more likely it is a hole type hidden damage; conversely, if the detection and recognition metric is closer to a small value, it means that the scattering degree of the hidden damage area is low and the regularity is high, and the more likely it is a crack type hidden damage.

[0070] The type of hidden damage of the metal casting is finally evaluated based on the detection and identification metric. Preferably, in one embodiment of the present invention, the method for evaluating the type of hidden damage of the metal casting includes:

[0071] The dark damage area whose detection and identification metric is greater than the preset division threshold is marked as a hole type dark damage area; the dark damage area whose detection and identification metric is not greater than the preset division threshold is marked as a crack type dark damage area. Preferably, in one embodiment of the present invention, the preset division threshold is 0.78:

[0072] For the above steps, the value of the detection and identification metric is compared with the preset division threshold. If the value of the detection and identification metric is greater than the preset division threshold of the hidden damage area, the hidden damage area is judged to be a hole-type hidden damage; if the value of the detection and identification metric is not greater than the preset division threshold of the hidden damage area, it is judged to be a crack-type hidden damage.

[0073] Furthermore, the inspectors take corresponding repair measures or quality control measures based on the evaluation results to improve the quality and reliability of the metal castings.

[0074] In summary, the embodiments of the present invention provide an ultrasonic nondestructive flaw detection method, system and device for metal castings. First, in the embodiments of the present invention, the hidden flaw measurement of the block area is obtained according to the abnormality and value of the echo duration of the block area; the hidden flaw area is divided from all the block areas according to the hidden flaw measurement; the echo scattering measurement of the hidden flaw area is obtained according to the energy dispersion of the ultrasonic echo signal in the frequency domain of the hidden flaw area; the echo correlation measurement of the hidden flaw area is obtained according to the correlation between the ultrasonic emission signal and the ultrasonic echo signal in the hidden flaw area; the detection and identification measurement of the hidden flaw area is obtained according to the echo scattering measurement and the echo correlation measurement; the hidden flaw type of the hidden flaw area in the metal casting is evaluated according to the detection and identification measurement of the hidden flaw area. The present invention improves the accuracy of hidden flaw evaluation of metal castings by fully considering the characteristics of the ultrasonic echo signal reflected by the hidden flaw area.

[0075] The present invention also proposes an ultrasonic nondestructive flaw detection system for metal castings, see Figure 3 , which shows a structural diagram of an ultrasonic non-destructive flaw detection system for metal castings provided by an embodiment of the present invention. The system includes: a data acquisition module 101, a hidden flaw area division module 102 and a hidden flaw type assessment module 103.

[0076] The data acquisition module 101 is used to perform ultrasonic nondestructive testing on metal castings, and acquire ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes echo duration and ultrasonic echo signals;

[0077] The dark damage area division module 102 is used to obtain the dark damage measurement of the block area according to the abnormal situation and value of the echo duration of the block area; and divide the dark damage area from all the block areas according to the dark damage measurement;

[0078] The hidden damage type assessment module 103 is used to obtain the echo scattering measurement of the hidden damage area according to the energy dispersion of the ultrasonic echo signal in the frequency domain of the hidden damage area; to obtain the echo correlation measurement of the hidden damage area according to the correlation between the ultrasonic transmission signal and the ultrasonic echo signal in the hidden damage area; to obtain the detection and identification measurement of the hidden damage area according to the echo scattering measurement and the echo correlation measurement; and to evaluate the hidden damage type of the hidden damage area in the metal casting according to the detection and identification measurement of the hidden damage area.

[0079] An ultrasonic nondestructive flaw detection device for metal castings comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned ultrasonic nondestructive flaw detection methods for metal castings are implemented.

[0080] It should be noted that: the system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above. In addition, the ultrasonic non-destructive flaw detection system for metal castings and the ultrasonic non-destructive flaw detection method for metal castings provided in the above embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0081] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0082] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. An ultrasonic nondestructive testing method for metal castings, characterized in that: The method comprises: Performing ultrasonic nondestructive testing on metal castings to obtain ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes echo duration and ultrasonic echo signals; Obtaining a dark damage measure of the block area according to the abnormality and value of the echo duration of the block area; dividing the dark damage area from all the block areas according to the dark damage measure; According to the energy dispersion of the ultrasonic echo signal of the dark damage area in the frequency domain, the echo scattering metric of the dark damage area is obtained; according to the correlation between the ultrasonic emission signal and the ultrasonic echo signal of the dark damage area, the echo correlation metric of the dark damage area is obtained; according to the echo scattering metric and the echo correlation metric, the detection and identification metric of the dark damage area is obtained; according to the detection and identification metric of the dark damage area, the dark damage type of the dark damage area in the metal casting is evaluated; The method for obtaining the hidden damage metric includes: Based on the isolation forest method, the anomaly score of each block area is obtained according to the echo duration corresponding to all block areas; Forward fusion of the abnormal scores and the values ​​of the echo duration of each of the block regions to obtain a dark damage metric for each of the block regions; The method for obtaining the echo scattering metric includes: Based on Fourier transform, the ultrasonic echo signal corresponding to the dark injury area is converted from the time domain to the frequency domain to obtain the echo frequency domain signal corresponding to the dark injury area; In the echo frequency domain signal corresponding to the dark damage area, the frequency corresponding to the maximum amplitude is taken as the target frequency, and the average of all amplitudes is taken as the target amplitude; the sum of the target amplitude and the preset denominator adjustment value is calculated, and the ratio of the target frequency to the sum is calculated to obtain the echo scattering measurement of the dark damage area; The method for obtaining the echo correlation metric includes: Calculating the Pearson coefficient of the ultrasonic emission signal and the ultrasonic echo signal of the dark injury area and performing normalization processing to obtain an echo correlation measure of the dark injury area; The method for obtaining the detection and identification metric includes: The product of the negative correlation mapping result of the echo correlation metric of the dark damage area and the echo scattering metric is calculated and normalized to obtain the detection and identification metric of the dark damage area.

2. The ultrasonic nondestructive testing method for metal castings according to claim 1, characterized in that: The method for obtaining the hidden injury area includes: Among all the block regions of the metal casting, the block regions where the dark damage metric is greater than a preset dark damage threshold are regarded as dark damage regions.

3. The ultrasonic nondestructive testing method for metal castings according to claim 1, characterized in that: The method for evaluating the type of hidden damage of metal castings comprises: The dark damage area whose detection and identification metric is greater than the preset division threshold is marked as a hole type dark damage area; the dark damage area whose detection and identification metric is not greater than the preset division threshold is marked as a crack type dark damage area.

4. The ultrasonic nondestructive testing method for metal castings according to claim 3, characterized in that: The preset division threshold is 0.

78.

5. An ultrasonic nondestructive flaw detection system for metal castings, characterized in that: include: A data acquisition module, used for performing ultrasonic nondestructive testing on metal castings, acquiring ultrasonic emission signals and a reflection data set of each block area of ​​the metal casting; the reflection data set includes an echo duration and an ultrasonic echo signal; A dark damage area division module is used to obtain a dark damage measurement of a block area according to an abnormality and a value of an echo duration of the block area; and divide a dark damage area from all block areas according to the dark damage measurement; A hidden damage type assessment module, which obtains an echo scattering measure of the hidden damage area according to energy dispersion of the ultrasonic echo signal corresponding to the hidden damage area in the frequency domain; and obtains an echo correlation measure of the hidden damage area according to the correlation between the ultrasonic emission signal and the ultrasonic echo signal of the hidden damage area; Acquire a detection and identification metric of a dark damaged area according to the echo scattering metric and the echo correlation metric; Evaluating the type of hidden damage in the hidden damage area in the metal casting according to the detection and identification metric of the hidden damage area; The method for obtaining the hidden damage metric includes: Based on the isolation forest method, the anomaly score of each block area is obtained according to the echo duration corresponding to all block areas; Forward fusion of the abnormal scores and the values ​​of the echo duration of each of the block regions to obtain a dark damage metric for each of the block regions; The method for obtaining the echo scattering metric includes: Based on Fourier transform, the ultrasonic echo signal corresponding to the dark injury area is converted from the time domain to the frequency domain to obtain the echo frequency domain signal corresponding to the dark injury area; In the echo frequency domain signal corresponding to the dark damage area, the frequency corresponding to the maximum amplitude is taken as the target frequency, and the average of all amplitudes is taken as the target amplitude; the sum of the target amplitude and the preset denominator adjustment value is calculated, and the ratio of the target frequency to the sum is calculated to obtain the echo scattering measurement of the dark damage area; The method for obtaining the echo correlation metric includes: Calculating the Pearson coefficient of the ultrasonic emission signal and the ultrasonic echo signal of the dark injury area and performing normalization processing to obtain an echo correlation measure of the dark injury area; The method for obtaining the detection and identification metric includes: The product of the negative correlation mapping result of the echo correlation metric of the dark damage area and the echo scattering metric is calculated and normalized to obtain the detection and identification metric of the dark damage area.

6. An ultrasonic nondestructive flaw detection device for metal castings, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the ultrasonic non-destructive flaw detection method for metal castings as claimed in any one of claims 1 to 4 are implemented.

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