Heat exchange device pitting corrosion detection method and heat exchange device pitting corrosion detection equipment

Abstract

The invention relates to a heat exchange device pitting corrosion detection method and heat exchange device pitting corrosion detection device.The heat exchange device pitting corrosion detection method comprises the steps that in the salt spray test process of a heat exchange device, a target infrared thermal image of the heat exchange device is obtained; target area detection is carried out on the target infrared thermal image, when the target area exists in the target infrared thermal image, the temperature difference between the target area and a surrounding area and the shape of the target area are determined, and the target area comprises a bright area and / or a dark area; and according to the temperature difference and the shape of the target area, a target pitting corrosion result of the heat exchange device is obtained through analysis. According to the application, in-situ monitoring of pitting corrosion and pitting corrosion failure of the automobile heat exchange device is realized under the condition that the heat exchange device is not damaged.

Description

Technical Field

[0001] The present application relates to the field of heat exchanger detection, and particularly to a method for detecting pitting corrosion of a heat exchange device and a device for detecting pitting corrosion of a heat exchange device. Background Art

[0002] Automotive heat exchange devices usually use heat transfer fluids (such as air, exhaust gas, coolant, engine oil, lubricating oil, etc.) to cool devices such as engines, fuels, engine oils, and lubricating oils, and to control the temperature of the engine compartment and the cab. However, during use, with the erosion of the heat exchange device by the cooling medium, pitting corrosion may occur inside the device pipeline, and even point leakage of the cooling medium may cause the device to fail. Especially during vehicle driving, the failure of the heat exchange device has a serious impact on driving safety. Currently, the detection of pitting corrosion of heat exchange devices mainly involves cutting samples of heat exchange devices and making cross-sections to observe the pitting corrosion of heat exchange devices, but this method will damage the samples.

[0003] Regarding the problem in the related art that the pitting corrosion and pitting corrosion failure of automotive heat exchange devices cannot be monitored in-situ, no effective solution has been proposed yet. Summary of the Invention

[0004] In this embodiment, a method for detecting pitting corrosion of a heat exchange device and a device for detecting pitting corrosion of a heat exchange device are provided to solve the problem in the related art that the pitting corrosion and pitting corrosion failure of automotive heat exchange devices cannot be monitored in-situ.

[0005] In a first aspect, in this embodiment, a method for detecting pitting corrosion of a heat exchange device is provided, including:

[0006] During the salt spray test of the heat exchange device, obtaining a target infrared thermal image of the heat exchange device;

[0007] Performing target area detection on the target infrared thermal image. When the target area exists in the target infrared thermal image, determining the temperature difference between the target area and the surrounding area and the shape of the target area, where the target area includes a bright area and / or a dark area;

[0008] Analyzing and obtaining a target pitting corrosion result of the heat exchange device according to the temperature difference and the shape of the target area.

[0009] In some of these embodiments, the analyzing and obtaining a target pitting corrosion result of the heat exchange device according to the temperature difference and the shape of the target area includes:

[0010] When the target area only includes bright areas, analyze the temperature difference between the bright areas in the target infrared thermal image and the bright areas in the surrounding intact areas, and the area shape of the bright areas in the target infrared thermal image, to obtain the first pitting result of the heat exchange device; use the first pitting result as the target pitting result;

[0011] When the target area only includes dark areas, analyze the temperature difference between the dark areas in the target infrared thermal image and the dark areas in the surrounding intact areas, and the area shape of the dark areas in the target infrared thermal image, to obtain the second pitting result of the heat exchange device; use the second pitting result as the target pitting result;

[0012] When the target area includes both bright areas and dark areas, combine the first pitting result and the second pitting result to obtain the target pitting result.

[0013] In some embodiments, the analyzing the temperature difference between the bright areas in the target infrared thermal image and the bright areas in the surrounding intact areas, and the area shape of the bright areas in the target infrared thermal image, to obtain the first pitting result of the heat exchange device, includes:

[0014] When the temperature difference of the bright areas is within a preset first temperature difference range, if the shape of the bright areas is small dot-like, it is determined that the wall thickness of the heat exchange device is reduced, and coating pitting cracking occurs in the heat exchange device;

[0015] When the temperature difference of the bright areas is within a preset second temperature difference range, if the shape of the bright areas is a concentric ring or an elliptical ring, it is determined that the wall thickness of the heat exchange device is reduced, and pitting of the heat exchange device extends circumferentially;

[0016] When the temperature difference of the bright areas is within a preset second temperature difference range, if the shape of the bright areas is small dot-like or irregular, it is determined that the wall thickness of the heat exchange device is reduced, and pitting of the heat exchange device extends along the wall;

[0017] Wherein, the first temperature difference range is smaller than the second temperature difference range.

[0018] In some embodiments, the analyzing the temperature difference between the dark areas in the target infrared thermal image and the dark areas in the surrounding intact areas, and the area shape of the dark areas in the target infrared thermal image, to obtain the second pitting result of the heat exchange device, includes:

[0019] When the temperature difference of the dark areas is within a preset third temperature difference range, if the shape of the dark areas is irregular, it is determined that there is an impurity mass defect in the heat exchange device;

[0020] When the temperature difference in the dark area is within a preset fourth temperature difference range, if the shape of the dark area is circular or oval, it is determined that the coating of the heat exchange device has bubbled and there are air bubbles in the internal pipeline of the heat exchange device;

[0021] When the temperature difference in the dark area is within a preset fourth temperature difference range, if the shape of the dark area is small dot-shaped or irregular, it is determined that the heat exchange device has suffered pitting failure;

[0022] Wherein, the third temperature difference range is smaller than the fourth temperature difference range.

[0023] In some embodiments, during the salt spray test of the heat exchange device, it further includes:

[0024] Performing real-time pressure detection on the heat exchange device with the pipeline outlet in a sealed state to obtain a real-time pressure value;

[0025] Calculating the pressure difference between the real-time pressure value and the initial pressure value; the initial pressure value is obtained by the initial detection when the heat exchange device is sealed;

[0026] When the pressure difference reaches a preset pressure difference threshold, it is determined that the heat exchange device has suffered pitting failure and a pitting failure warning message is sent.

[0027] In some embodiments, according to the pressure difference, the leakage amount of the heat exchange device suffering pitting failure is determined;

[0028] According to the leakage amount, the service life of the heat exchange device is determined.

[0029] In some embodiments, during the salt spray test of the heat exchange device, it further includes:

[0030] Obtaining weak magnetic monitoring data of the area where the heat exchange device is located;

[0031] Drawing a weak magnetic monitoring data curve graph according to the weak magnetic monitoring data;

[0032] Determining the positions where the heat exchange device has suffered pitting as the positions of the peaks and valleys in the weak magnetic monitoring data curve graph.

[0033] In some embodiments, during the salt spray test of the heat exchange device, it further includes:

[0034] Applying a constant current to the heat exchange device based on a galvanostat or applying a constant voltage to the heat exchange device based on a potentiostat to accelerate the corrosion rate of the heat exchange device during the salt spray test.

[0035] In some of these embodiments, during the salt spray test of the heat exchange device, it further includes:

[0036] Based on the ion concentration of the heat exchange device detected by the in-situ concentration monitoring device connected to the inside of the heat exchange device, determine whether pitting corrosion occurs in the heat exchange device; or,

[0037] Based on the pH value inside the heat exchange device detected by the pH meter connected to the inside of the heat exchange device, determine whether pitting corrosion occurs in the heat exchange device.

[0038] Second aspect, in this embodiment, a pitting corrosion detection device for a heat exchange device is provided, which applies the pitting corrosion detection method for a heat exchange device described in the first aspect above. The pitting corrosion detection device for a heat exchange device includes: an in-situ infrared thermal imager, a pressure monitoring device, a weak magnetic detector, a galvanostat, a potentiostat, an in-situ concentration monitoring device, a pH meter, and an analysis device; wherein:

[0039] The in-situ infrared thermal imager is arranged on the outer side of the heat exchange device, and is used to collect the target infrared thermal image of the heat exchange device and transmit the target infrared thermal image to the analysis device, so that the analysis device determines the pitting corrosion situation of the heat exchange device according to the target infrared thermal image;

[0040] The pressure monitoring device is arranged at the inlet of the heat exchange device, and is used to detect the real-time pressure value of the heat exchange device and transmit the real-time pressure value to the analysis device, so that the analysis device determines whether pitting corrosion failure occurs in the heat exchange device according to the real-time pressure value;

[0041] The weak magnetic detector is arranged around the heat exchange device, and is used to scan the area where the heat exchange device is located to obtain weak magnetic monitoring data; and transmit the weak magnetic monitoring data to the analysis device, so that the analysis device analyzes and obtains the position where pitting corrosion occurs in the heat exchange device according to the weak magnetic monitoring data;

[0042] The galvanostat and the potentiostat are connected to the heat exchange device, and are used to apply a constant current or a constant voltage to the heat exchange device to accelerate the corrosion rate of the heat exchange device during the salt spray test;

[0043] The in-situ concentration monitoring device is arranged inside the heat exchange device, and is used to detect the ion concentration of the heat exchange device and transmit the ion concentration to the analysis device, so that the analysis device determines the pitting corrosion situation of the heat exchange device according to the ion concentration;

[0044] The pH meter is disposed inside the heat exchange device, and is used to detect the pH value inside the heat exchange device and transmit the pH value to the analysis device, so that the analysis device can judge the pitting corrosion condition of the heat exchange device according to the pH value.

[0045] Compared with the related art, in the pitting corrosion detection method of the heat exchange device provided in this embodiment, during the salt spray test of the heat exchange device, a target infrared thermal image of the heat exchange device is obtained; target area detection is performed on the target infrared thermal image. When the target area exists in the target infrared thermal image, the temperature difference between the target area and the surrounding area and the shape of the target area are determined, wherein the target area includes a bright area and / or a dark area; according to the temperature difference and the shape of the target area, the target pitting corrosion result of the heat exchange device is analyzed, realizing in-situ monitoring of the pitting corrosion and pitting corrosion failure of the automotive heat exchange device without damaging the heat exchange device.

[0046] Details of one or more embodiments of the present application are set forth in the following drawings and description, so that other features, objects, and advantages of the present application become more concise and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0048] Figure 1 is a hardware structure block diagram of the terminal of the pitting corrosion detection method of the heat exchange device in this embodiment.

[0049] Figure 2 is a flowchart of the pitting corrosion detection method of the heat exchange device in this embodiment.

[0050] Figure 3a is an example diagram of the area shape when the temperature difference of the bright area of the pitting corrosion detection method of the heat exchange device in this embodiment is within a preset first temperature difference range.

[0051] Figure 3b is an example diagram of the area shape when the temperature difference of the bright area of the pitting corrosion detection method of the heat exchange device in this embodiment is within a preset second temperature difference range.

[0052] Figure 3c is another example diagram of the area shape when the temperature difference of the bright area of the pitting corrosion detection method of the heat exchange device in this embodiment is within a preset second temperature difference range.

[0053] Figure 4a is an example diagram of the area shape when the temperature difference of the dark area of the pitting corrosion detection method of the heat exchange device in this embodiment is within a preset third temperature difference range.

[0054] Figure 4b It is an example diagram of the shape of the area where the temperature difference in the dark area of the pitting detection method for the heat exchange device in this embodiment is within the preset fourth temperature difference range.

[0055] Figure 4c It is another example diagram of the shape of the area where the temperature difference in the dark area of the pitting detection method for the heat exchange device in this embodiment is within the preset fourth temperature difference range.

[0056] Figure 5 It is a weak magnetic monitoring data diagram in the pitting detection method for the heat exchange device in this embodiment.

[0057] Figure 6 It is a flowchart of another pitting detection method for the heat exchange device in this embodiment.

[0058] Figure 7 It is a structural block diagram of the pitting detection device for the heat exchange device in this embodiment. Detailed implementation manners

[0059] For a clearer understanding of the purpose, technical solution, and advantages of this application, the following describes and explains this application in combination with the accompanying drawings and embodiments.

[0060] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by those with ordinary skills in the technical field to which this application belongs. In this application, words such as "a", "one", "a kind of", "the", "these", etc. do not indicate a limitation in quantity, and they can be singular or plural. The terms "including", "comprising", "having" and any variants thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device including a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products, or devices. The terms "connected", "coupled", etc. involved in this application do not limit to physical or mechanical connections, but may include electrical connections, whether directly or indirectly connected. The term "a plurality of" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " indicates that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application only distinguish similar objects and do not represent a specific sorting for the objects.

[0061] The method embodiments provided in this embodiment may be executed on a terminal, a computer, or a similar computing device. For example, when running on a terminal, Figure 1 is a hardware block diagram of the terminal for the pitting corrosion detection method of the heat exchange device in this embodiment. As Figure 1 shown, the terminal may include one or more ( Figure 1 only one is shown in the figure) processors 102 and a memory 104 for storing data. Among them, the processor 102 may include, but is not limited to, a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may also include a transmission device 106 for communication functions and an input / output device 108. Those of ordinary skill in the art can understand that Figure 1 the structure shown is only schematic and does not limit the structure of the above terminal. For example, the terminal may further include more or fewer components than Figure 1 shown in the figure, or have a different configuration from Figure 1 shown in the figure.

[0062] The memory 104 can be used to store computer programs. For example, software programs and modules of application software, such as the computer program corresponding to the pitting corrosion detection method of the heat exchange device in this embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implements the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some instances, the memory 104 may further include a memory remotely provided with respect to the processor 102, and these remote memories may be connected to the terminal through a network. Examples of the above network include, but are not limited to, the Internet, an enterprise internal network, a local area network, a mobile communication network, and combinations thereof.

[0063] The transmission device 106 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one instance, the transmission device 106 includes a network adapter (abbreviated as NIC), which can be connected to other network devices through a base station and thus can communicate with the Internet. In one instance, the transmission device 106 may be a radio frequency (abbreviated as RF) module, which is used to communicate with the Internet wirelessly.

[0064] In this embodiment, a pitting corrosion detection method for a heat exchange device is provided. Figure 2 is a flowchart of the pitting corrosion detection method for the heat exchange device in this embodiment. As Figure 2 shown, the process includes the following steps:

[0065] Step S201, during the salt spray test of the heat exchange device, obtain the target infrared thermal image of the heat exchange device.

[0066] Specifically, pitting corrosion is a form of local corrosion. Usually, corrosion pits are formed on the material surface. These corrosion pits may be blocked by corrosion products and are difficult to be detected in time, resulting in sudden accidents. Pitting corrosion failure refers to the phenomenon that in a corrosive medium, due to the destruction of the protective film or passivation film in a local area of the metal material, small hole-shaped corrosion defects are formed, which further leads to the decline of material performance and even the failure of the structure. For the convenience of description, in this embodiment, an automotive heat exchange device is taken as an example for illustration. It can be understood that other heat exchange devices are also applicable to the pitting corrosion detection method of this embodiment, and this embodiment does not make specific limitations in this regard. Currently, in the existing related technologies, after the salt spray test of the heat exchange device, the pitting corrosion situation of the heat exchange device after the test is mainly observed by cutting the sample of the heat exchange device and making a cross-section. This often damages the sample, and a large amount of equipment and time are required for cutting the sample, and the detection efficiency is relatively low. In response to this, in this embodiment, an in-situ infrared thermal imager is introduced to inspect the heat exchange device during the test. Among them, when the heat exchange device is corroded, the corrosion reaction will generate a certain amount of heat, resulting in the temperature of the corrosion area being higher than that of the surrounding normal parts. In this embodiment, an in-situ infrared thermal imager is set around the heat exchange device to detect the invisible infrared heat emitted by the heat exchange device, and the detected invisible infrared heat emitted by the heat exchange device is converted into a visible target infrared thermal image, so as to obtain the temperature distribution of the heat exchange device.

[0067] Exemplarily, in this embodiment, the wavelength of the acquisition module of the infrared thermal imager can be set to 2μm - 6μm, the resolution can be set to higher than 640×512, the temperature resolution can be set to lower than 0.1℃, the acquisition area of the acquisition module can at least cover 1 / 4 of the surface area of the heat exchange device, and the number of acquisition modules of the infrared thermal imager is increased according to the surface area size to ensure that the acquisition range of the infrared thermal imager can cover the entire surface of the heat exchange device. The acquisition module acquires the infrared thermal image of the entire surface of the heat exchange device at least once within 1 minute, and transmits the acquired target infrared thermal image to the display of the analysis device outside the salt spray test chamber.

[0068] Step S202, perform target area detection on the target infrared thermal image. When the target area exists in the target infrared thermal image, determine the temperature difference between the target area and the surrounding area and the shape of the target area, where the target area includes bright areas and / or dark areas.

[0069] After acquiring the target infrared thermal image of the heat exchange device, if there is pitting on the surface of the heat exchange device, due to the different heat conduction characteristics of the pitting area from the normal area, different bright and dark areas will be formed in the target infrared thermal image. If there is no pitting, the surface temperature distribution of the heat exchange device is relatively uniform, and the target infrared thermal image will show a relatively consistent color. If there is pitting, bright areas or dark areas, or both bright and dark areas will appear in the target infrared thermal image, and the appearance of these areas is due to the local temperature change caused by pitting. Therefore, after acquiring the target infrared thermal image, it is necessary to perform further target area detection on it to determine whether there are abnormal bright areas or dark areas. First, through image processing techniques (such as threshold segmentation, edge detection, etc.), it is judged whether there are bright areas or dark areas in the target infrared thermal image. The appearance of these areas represents the existence of pitting. When the target area is detected, the temperature difference between this area and the surrounding normal area is further analyzed. Among them, the area where there is no pitting or pitting failure is regarded as the normal area, and it shows a uniform color in the infrared thermal image. The magnitude of the temperature difference can reflect the severity of pitting. A large temperature difference indicates that the pitting is deeper and the corrosion degree is more serious. A small temperature difference indicates that the pitting is shallower and the corrosion degree is relatively lighter. In addition, based on the temperature difference, the shape of the target area also needs to be detected. Different shapes of the target area correspond to different pitting situations. Among them, the shape of the target area may be small dot-like, concentric circles or other irregular shapes.

[0070] Step S203: Analyze and obtain the target pitting result of the heat exchange device according to the temperature difference and the shape of the target area.

[0071] Specifically, pitting analysis is performed by comprehensively considering the brightness and darkness, temperature difference, and shape of the target area. Different brightness and darkness situations, temperature differences, and shapes of the target area correspond to different pitting results.

[0072] In some embodiments, analyzing and obtaining the target pitting result of the heat exchange device according to the temperature difference and the shape of the target area includes:

[0073] When the target area only includes bright areas, analyze the temperature difference between the bright areas in the target infrared thermal image and the bright areas of the surrounding intact areas and the area shape of the bright areas in the target infrared thermal image to obtain the first pitting result of the heat exchange device; use the first pitting result as the target pitting result.

[0074] Specifically, the bright area of the target infrared thermal image is the area where pitting occurs. If there is a bright area in the infrared thermal image, it indicates that pitting has occurred in the target area. Based on the judgment of the bright area, calculate the temperature difference between the bright area and the surrounding intact area, and analyze the pitting result in combination with the shape of the bright area that appears. Different temperature differences and different bright area shapes correspond to different pitting results. For example, when there is a small dot-shaped bright area with a small temperature difference, it can be judged that pitting has occurred in the heat exchange device, and it can be judged that it is caused by the coating cracking of the heat exchange device. Record the pitting result as the first pitting result. If there is only this bright area in the target infrared thermal image, then determine the pitting result obtained from the analysis of this bright area as the target pitting result.

[0075] When the target area only includes a dark area, analyze the temperature difference between the dark area in the reference infrared thermal image and the surrounding intact area and the area shape of the dark area in the target infrared thermal image to obtain the second pitting result of the heat exchange device; use the second pitting result as the target pitting result.

[0076] Specifically, the dark area of the target infrared thermal image is the area where pitting failure may occur. Similarly, if there is a dark area in the infrared thermal image, it indicates that pitting failure has occurred in the target area. Based on the judgment of the dark area, calculate the temperature difference between the dark area and the surrounding intact area, and analyze the pitting result in combination with the shape of the dark area that appears. Different temperature differences and different dark area shapes correspond to different pitting results. For example, when there is a small dot-shaped dark area with a large temperature difference, it can be judged that pitting failure has occurred in the heat exchange device, and it can be judged that it is caused by perforation of the heat exchange device. Record the pitting failure result as the second pitting result. If there is only this dark area in the target infrared thermal image, then determine the pitting result obtained from the analysis of this dark area as the target pitting result.

[0077] When the target area includes both a bright area and a dark area, obtain the target pitting result by combining the first pitting result and the second pitting result.

[0078] Specifically, if the target area of the detected infrared thermal image includes both a bright area and a dark area, perform detection and analysis on the bright area and the dark area respectively according to the above detection method, and combine the detected first pitting result and the second pitting result to obtain the target pitting result.

[0079] Through the above steps S201 to S203, during the salt spray test of the heat exchange device, the target infrared thermal image of the heat exchange device is obtained; the target area of the target infrared thermal image is detected. When there is a target area in the target infrared thermal image, the temperature difference between the target area and the surrounding area and the shape of the target area are determined, where the target area includes a bright area and / or a dark area; according to the temperature difference and the shape of the target area, the target pitting result of the heat exchange device is analyzed. Compared with the prior art in which the sample of the heat exchange device is cut to make a cross-section to observe the pitting situation of the heat exchange device, in this embodiment, by collecting the target infrared thermal image of the heat exchange device during the salt spray test, and analyzing and judging the temperature difference and shape of the target area in the target infrared thermal image, the pitting result and the cause of pitting are obtained, avoiding the damage to the heat exchange device, and realizing the in-situ detection of the pitting and pitting failure of the automotive heat exchange device.

[0080] In some of these embodiments, the temperature difference between the bright area in the target infrared thermal image and the bright area of the surrounding intact area and the area shape of the bright area in the target infrared thermal image are analyzed to obtain the first pitting result of the heat exchange device, including:

[0081] When the temperature difference of the bright area is within the preset first temperature difference range, if the shape of the bright area is small dots, it is determined that the wall thickness of the heat exchange device is reduced and the coating of the heat exchange device has pitting cracks;

[0082] When the temperature difference of the bright area is within the preset second temperature difference range, if the shape of the bright area is a concentric ring or an elliptical ring, it is determined that the wall thickness of the heat exchange device is reduced and the pitting of the heat exchange device extends circumferentially;

[0083] When the temperature difference of the bright area is within the preset second temperature difference range, if the shape of the bright area is small dots or an irregular shape, it is determined that the wall thickness of the heat exchange device is reduced and the pitting of the heat exchange device extends along the wall;

[0084] Among them, the first temperature difference range is smaller than the second temperature difference range.

[0085] Specifically, in the above step S203, when the target area is a bright area, different pitting results can be obtained according to different temperature differences of the bright area combined with different area shapes. Figure 3a It is an example diagram of the area shape when the temperature difference of the bright area of the pitting detection method of the heat exchange device in this embodiment is within the preset first temperature difference range. As Figure 3a shown, when the temperature difference of the bright area is within the preset first temperature difference range of 0°C - 1°C and the shape of the bright area is small dots, it can be analyzed that pitting occurs at this place of the heat exchange device, and the wall thickness of the heat exchange device at this place is reduced, and it can be determined that the pitting situation is caused by the coating cracking of the heat exchange device at this place. Figure 3bIt is an example diagram of the shape of the area where the temperature difference of the bright area in the pitting detection method of the heat exchange device in this embodiment is within the preset second temperature difference range. As Figure 3b shown, when the temperature difference of the bright area is greater than 1°C within the preset second temperature difference range and the shape of the bright area is a concentric ring or an elliptical ring, it can be analyzed that pitting occurs at this place of the heat exchange device, and the wall thickness of the heat exchange device at this place is reduced. Moreover, it can be determined that the pitting of the heat exchange device at this place expands circumferentially, that is, the trend of pitting is to expand horizontally outward in the plane where the wall of the heat exchange device is located, and the pitting area shows an expanding trend. Figure 3c It is another example diagram of the shape of the area where the temperature difference of the dark area in the pitting detection method of the heat exchange device in this embodiment is within the preset second temperature difference range. As Figure 3c shown, when the temperature difference of the dark area is greater than 1°C within the preset second temperature difference range and the shape of the dark area is a small dot or an irregular shape, it can be analyzed that pitting occurs at this place of the heat exchange device, and the wall thickness of the heat exchange device at this place is reduced. Moreover, it can be determined that the pitting of the heat exchange device at this place expands along the wall, that is, the trend of pitting is to expand vertically from the inside to the outside in the plane where the wall of the heat exchange device is located, and there may be a trend of perforation in the pitting area, which may lead to pitting failure.

[0086] In another embodiment, by analyzing the temperature difference between the dark area and the surrounding intact area in the target infrared thermal image and the shape of the dark area in the target infrared thermal image, a second pitting result of the heat exchange device is obtained, including:

[0087] When the temperature difference of the dark area is within the preset third temperature difference range, if the shape of the dark area is an irregular shape, it is determined that the heat exchange device has an impurity mass defect;

[0088] When the temperature difference of the dark area is within the preset fourth temperature difference range, if the shape of the dark area is a circle or an ellipse, it is determined that the coating of the heat exchange device bulges and there are air bubbles in the internal pipeline of the heat exchange device;

[0089] When the temperature difference of the dark area is within the preset fourth temperature difference range, if the shape of the dark area is a small dot or an irregular shape, it is determined that the heat exchange device has pitting failure;

[0090] Among them, the third temperature difference range is smaller than the fourth temperature difference range.

[0091] Specifically, in the above step S203, when the target area is a dark area, different pitting results can be obtained by combining different temperature differences of the dark area with different area shapes. Figure 4a It is an example diagram of the shape of the area where the temperature difference of the dark area in the pitting detection method of the heat exchange device in this embodiment is within the preset third temperature difference range. As Figure 4aAs shown in the figure. When the temperature difference in the dark area is within the preset third temperature difference range of 0°C - 1°C and the shape of the dark area is irregular, it can be analyzed that there are mass defects such as impurities in the heat exchange device at this position. This dark area may be caused by impurities in the wall of the heat exchange device. Figure 4b It is an example diagram of the shape of the area where the temperature difference in the dark area of the pitting corrosion detection method of the heat exchange device in this embodiment is within the preset fourth temperature difference range. As Figure 4b shown in the figure, when the temperature difference in the dark area is greater than 1°C within the preset fourth temperature difference range and the shape of the dark area is circular or elliptical, it can be analyzed that the coating at this position of the heat exchange device bulges, or there are large bubbles in the internal pipeline of the heat exchange device. There may be a perforation situation at this position, resulting in pitting corrosion failure. Figure 4c It is another example diagram of the shape of the area where the temperature difference in the dark area of the pitting corrosion detection method of the heat exchange device in this embodiment is within the preset fourth temperature difference range. As Figure 4c shown in the figure, when the temperature difference in the dark area is greater than 1°C within the preset fourth temperature difference range and the shape of the dark area is small dot-shaped or irregular, it can be analyzed that there is a perforation phenomenon in the heat exchange device at this position, and pitting corrosion failure occurs at this position.

[0092] Therefore, in this embodiment, by collecting the target infrared thermal image of the heat exchange device in the salt spray test and combining the brightness and darkness of the target area and the area shape presented under different temperature differences, it is possible to realize in-situ monitoring of the pitting corrosion situation, pitting corrosion cause, and pitting corrosion trend judgment of the heat exchange device during the salt spray test, avoiding damage to the heat exchange device, and realizing in-situ detection of pitting corrosion and pitting corrosion failure of the automotive heat exchange device.

[0093] In some of these embodiments, during the salt spray test of the heat exchange device, it further includes:

[0094] For the heat exchange device under the sealed state of the pipeline outlet, perform real-time pressure detection to obtain the real-time pressure value; calculate the pressure difference between the real-time pressure value and the initial pressure value; the initial pressure value is obtained by the initial detection when the heat exchange device is sealed; when the pressure difference reaches the preset pressure difference threshold, it is determined that the heat exchange device has pitting corrosion failure, and a pitting corrosion failure warning message is sent.

[0095] Specifically, in addition to the above pitting corrosion detection of the heat exchange device by the in-situ infrared thermal imager, in this embodiment, a pressure monitoring device is also introduced to perform pressure detection on the heat exchange device, and whether the heat exchange device has pitting corrosion failure is judged by the change of the pressure value.

[0096] First, place the heat exchange device in a forced-air drying oven at 100 - 180 °C for 1 - 2 hours to remove any possible moisture on the surface and inside the heat exchange device, preventing moisture from interfering with the test results during subsequent gas filling or salt spray testing, such as affecting the stability of gas pressure or changing the corrosion environment of the salt spray test. After drying, cool it under a protective atmosphere, preferably using nitrogen as the protective gas. Nitrogen has stable chemical properties and is not easily reactive with other substances, which can prevent the heat exchange device from being oxidized during the cooling process. Seal the pipeline outlet of the heat exchange device, preferably by welding. Welding can provide good sealing performance to ensure that gas does not leak from the outlet during subsequent gas filling and testing processes. While sealing the pipeline inlet, connect an inner spring airtight core. This airtight core has a spring structure inside, which can facilitate gas filling or water operations and can also be connected to a pressure sensing device. Fill the heat exchange device with gas or water at 1.8 bar - 8 bar (1 bar is equal to 100,000 pascals (Pa)) through the airtight core. The gas is preferably compressed air or nitrogen. Compressed air is easily obtainable and has a low cost. Nitrogen, due to its larger molecules, is not easily permeable through the tiny pores of the material and can better maintain pressure stability. Connect the pressure monitoring device to the airtight core to monitor the pressure changes inside the heat exchanger in real time. The pressure monitoring device can be a pressure sensor, which can be specifically selected according to the actual situation, and this embodiment does not make specific limitations on this.

[0097] Then, place the heat exchange device equipped with the pressure sensor in a cyclic salt spray chamber, where the distance between the heat exchange device and the nozzle in the length and width directions is greater than 20 cm, and the distance from the four edges of the chamber is greater than 10 cm. This is to avoid the heat exchange device being directly impacted by the salt spray from the nozzle and to ensure that the heat exchange device is in the effective corrosion environment of the salt spray chamber.

[0098] During the salt spray test, first collect the initial pressure value when the heat exchange device is completely sealed. Then, collect the pressure data once every 1 second to obtain the real-time pressure value, and transmit the real-time pressure value to the display of the analysis device outside the salt spray test chamber via Bluetooth, and record it as a curve at the same time.

[0099] Calculate the pressure difference between the real-time pressure value and the initial pressure value ( ), and set that when the real-time pressure value drops by 5% - 10% compared to the initial pressure value, that is, the pressure difference ( When it reaches the preset 5% - 10%, a pitting failure alarm is issued to remind the tester that pitting failure has occurred in the heat exchange device, so that the tester can record the test data in time. When the pressure difference reaches the preset pressure difference threshold, it means that the heat exchange device has leaked under the action of salt spray corrosion, that is, pitting failure has occurred. The specific pressure difference threshold can be set according to the actual situation, and this embodiment does not make specific limitations. Through the pressure monitoring device, pitting failure can be warned in time without damaging the heat exchange device sample.

[0100] In another embodiment, according to the pressure difference, the leakage amount of the heat exchange device when pitting failure occurs is determined; according to the leakage amount, the service life of the heat exchange device is determined.

[0101] Specifically, in the above embodiment, after detecting and warning pitting failure by setting up a pressure monitoring device, according to the obtained pressure difference ( ), the leakage amount of the heat exchange device when pitting failure occurs can also be calculated. The specific calculation formula is as follows:

[0102] ;

[0103] where a is the leakage amount coefficient, taking 0.0006; v is the total volume of the heat exchanger and the test loop; is the pressure difference generated by the pressure sensing device within

[0104] In the salt spray corrosion test, record the time when the leakage amount exceeds 5% of the volume of the heat exchange device, and use this time as a reference for the salt spray corrosion life of the heat exchange device. When the leakage amount reaches 5% of the volume, it means that the sealing performance of the device has significantly decreased and may not meet the actual use requirements. Therefore, this time point can be used as a sign of the failure of the heat exchange device. In this way, the performance of the heat exchange device in different corrosion environments can be quantitatively evaluated, providing an important basis for product design optimization and service life prediction.

[0105] In some of the embodiments, during the salt spray test of the heat exchange device, it further includes: obtaining weak magnetic monitoring data of the area where the heat exchange device is located; drawing a weak magnetic monitoring data curve graph according to the weak magnetic monitoring data; determining the positions of the peaks and valleys in the weak magnetic monitoring data curve graph as the positions where pitting occurs on the heat exchange device.

[0106] Specifically, on the basis of detecting pitting of the heat exchange device by an in-situ infrared thermal imager or detecting pitting and pitting failure of the heat exchange device by combining an in-situ infrared thermal imager with a pressure monitoring device, this embodiment further introduces a weak magnetic detector to further detect the pitting situation of the heat exchange device.

[0107] During the salt spray test, a weak magnetic detector is used to collect magnetic signals in real time in the area where the heat exchange device is located. The weak magnetic detection technology uses the change of magnetic signals to reflect the corrosion condition of materials. When pitting occurs on the surface of the heat exchange device, its magnetic signals will change significantly, and these changes can be recorded by the detector. The weak magnetic detector monitors the change of magnetic induction intensity through a weak magnetic probe. Among them, the measuring range of the weak magnetic probe is ≥|250000|nT, the resolution is ≤0.1nT, the sampling frequency is ≥12.5Hz. The weak magnetic probe is perpendicular to the heat exchange device, and a fixed horizontal slide rail is set under the weak magnetic probe. The weak magnetic probe moves uniformly on the slide rail and ensures that it can scan the heat exchange device once within 3 minutes. The sampling coordinate system is perpendicular to the Bz-axis magnetic induction intensity of the heat exchange device. Specifically, the number of weak magnetic probes can be increased according to the surface area of the heat exchange device, and this embodiment does not make specific limitations on this.

[0108] The collected weak magnetic monitoring data is plotted as a curve graph. Record the abnormal conditions of magnetic induction intensity (appearance of peaks and valleys), and determine the pitting occurrence position on the heat exchange device according to the coordinate positions. Figure 5 is the weak magnetic monitoring data graph in the pitting detection method of the heat exchange device in this embodiment, as Figure 5 shown. The abscissa is the distance from the leftmost end of the salt spray chamber (unit: cm), and the ordinate is the magnetic induction intensity (unit: nT). Among them, the blue curve is the magnetic signal curve graph detected by the weak magnetic detector in the area where the heat exchange device is located before the experiment, and the orange curve is the magnetic signal curve graph detected by the weak magnetic detector in the area where the heat exchange device is located after 1800h of salt spray test. As Figure 5 shown, by analyzing the waveform characteristics of the curve graph, the change trend of magnetic signals can be intuitively observed. In the weak magnetic monitoring data curve graph, the positions of peaks and valleys usually correspond to the areas where pitting occurs on the surface of the heat exchange device. This is because pitting will cause abnormal changes in the local magnetic field, which are manifested as obvious peaks or valleys on the curve graph. By analyzing the positions of these characteristic points, the specific positions where pitting occurs can be accurately determined. As Figure 5 shown, after 1800h of salt spray test, the heat exchange device has pitting defects at 20cm, 53cm, 92cm, and 117cm from the leftmost end of the salt spray chamber.

[0109] Specifically, use a weak magnetic detector to scan the surface of the heat exchange device and collect the magnetic induction intensity differences between a large number of peaks and valleys ( ). At the same time, use high-precision detection equipment (such as industrial CT scanning, profilometer, white light interferometer, etc.) to measure the actual pitting pit depth at the corresponding positions. The collected magnetic induction intensity differences ( ) and the actual pit depth data are collated, and a relationship expression between the two is established using computer fitting technology (such as the least squares method). The relationship expression obtained through fitting can be directly used to calculate the depth of the pit according to the weak magnetic detector. The pitting depth of the heat exchanger can be quickly calculated by using the value. This method improves the detection efficiency and can also achieve efficient and accurate detection of the pitting depth of heat exchange components, providing strong support for the health management and preventive maintenance of heat exchange components.

[0110] In another embodiment, during the salt spray test of the heat exchange device, the method further comprises:

[0111] A constant current is applied to the heat exchange device based on a constant current meter or a constant voltage is applied to the heat exchange device based on a constant potential meter to accelerate the corrosion rate of the heat exchange device during the salt spray test.

[0112] Specifically, in the process of performing pitting corrosion detection on the heat exchange device by the in-situ infrared thermal imager or performing pitting corrosion and pitting corrosion failure detection on the heat exchange device by the in-situ infrared thermal imager combined with the pressure monitoring device, in order to accelerate the corrosion rate of the salt spray test and shorten the salt spray test cycle, a constant current meter and a constant potential meter are also introduced in this embodiment. Among them, the heat exchange device is connected to the positive electrode of the constant current meter, and the negative electrode is made of stainless steel or other suitable metal materials. By applying a constant current of 2mA-30mA for 1h-48h, the occurrence and development of pitting corrosion can be induced in a relatively short time, thereby accelerating the corrosion rate of the salt spray test and shortening the salt spray test cycle. The heat exchange device is connected to the positive electrode of the constant potential meter, and the negative electrode is made of stainless steel or other suitable metal materials. By applying a constant voltage of 0.1-0.8V for 1h-48h, the occurrence and development of pitting corrosion can be induced in a relatively short time, thereby accelerating the corrosion rate of the salt spray test and shortening the salt spray test cycle. Through the electrochemical accelerated corrosion method, the corrosion process in a long-term salt spray environment can be simulated in a short time, and information on the occurrence and development of pitting corrosion can be quickly obtained.

[0113] In some embodiments, during the salt spray test of the heat exchange device, the process further includes:

[0114] Whether pitting corrosion occurs in the heat exchange device can be determined by detecting the ion concentration of the heat exchange device by an in-situ concentration monitoring device connected to the inside of the heat exchange device; or, whether pitting corrosion occurs in the heat exchange device can be determined by detecting the pH value of the heat exchange device by a pH meter connected to the inside of the heat exchange device.

[0115] Specifically, based on the above method of detecting pitting corrosion of the heat exchange device by in-situ infrared thermal imager or detecting pitting corrosion and pitting corrosion failure of the heat exchange device by combining in-situ infrared thermal imager with a pressure monitoring device, an in-situ concentration monitoring device and a pH meter are introduced in this embodiment to detect the pitting corrosion situation of the heat exchange device.

[0116] By accessing the in-situ concentration monitoring device inside the heat exchange device, the ion concentration inside the heat exchange device is detected in real time. When pitting corrosion occurs in the heat exchange device, the corrosion products will dissolve into the solution, resulting in a change in the ion concentration. For example, for a heat exchange device made of metal material, pitting corrosion may cause a significant increase in the concentration of metal ions (such as iron ions, copper ions, etc.). By monitoring the changes in these ion concentrations, it can be determined whether pitting corrosion has occurred in the heat exchange device.

[0117] By accessing the pH meter inside the heat exchange device, the pH value inside the heat exchange device is detected in real time. Pitting corrosion is usually accompanied by local corrosion reactions, which will change the acidity and alkalinity of the solution. For example, in a salt spray test, the corrosion reaction may cause a local increase in acidity, resulting in a decrease in the pH value. By monitoring the change in the pH value, especially when the pH value shows a significant decrease, it can be determined whether pitting corrosion has occurred in the heat exchange device.

[0118] Both of these methods adopt in-situ monitoring technology, which can obtain data in real time during the salt spray test and detect the occurrence and development of pitting corrosion in a timely manner. The changes in ion concentration and pH value can provide quantitative corrosion information, which helps to more accurately evaluate the corrosion resistance of the heat exchange device. By combining ion concentration monitoring and pH value monitoring, the corrosion situation of the heat exchange device in a salt spray environment can be evaluated more comprehensively, providing strong support for the maintenance and life prediction of the equipment.

[0119] In this embodiment, a method for detecting pitting corrosion of a heat exchange device is also provided. Figure 6 It is a flowchart of another method for detecting pitting corrosion of a heat exchange device in this embodiment, as Figure 6 shown, and this process includes the following steps:

[0120] Step S601, during the salt spray test of the heat exchange device, obtain the target infrared thermal image of the heat exchange device;

[0121] Step S602, perform target area detection on the target infrared thermal image. When there is a target area in the target infrared thermal image, judge the target area;

[0122] Step S603, when there is only a bright area in the target area, analyze the temperature difference between the bright area in the target infrared thermal image and the bright area of the surrounding intact area and the area shape of the bright area in the target infrared thermal image to obtain the first pitting corrosion result of the heat exchange device; use the first pitting corrosion result as the target pitting corrosion result;

[0123] Step S604: When there is only a dark area in the target area, analyze the temperature difference between the dark area in the target infrared thermal image and the surrounding intact area and the area shape of the dark area in the target infrared thermal image to obtain the second pitting result of the heat exchange device; use the second pitting result as the target pitting result.

[0124] Step S605: When the target area includes a bright area and a dark area, combine the first pitting result and the second pitting result to obtain the target pitting result.

[0125] Through the above steps S601 to S605, compared with the prior art of cutting samples of heat exchange devices to make cross-sections to observe the pitting situation of heat exchange devices, in this embodiment, by collecting the target infrared thermal images of heat exchange devices in salt spray tests and analyzing the temperature difference and shape of the target area (bright area and dark area) in the target infrared thermal images, the pitting result and the cause of pitting are obtained, avoiding damage to the heat exchange device and realizing in-situ detection of pitting and pitting failure of automotive heat exchange devices.

[0126] In this embodiment, a pitting detection device for heat exchange devices is also provided. This pitting detection device for heat exchange devices is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be repeated.

[0127] Figure 7 is the structural block diagram of the pitting detection device for heat exchange devices in this embodiment, as Figure 7 shown. The pitting detection device 70 for heat exchange devices includes: an in-situ infrared thermal imager 71, a pressure monitoring device 72, a weak magnetic detector 73, a galvanostat 74, a potentiostat 75, an in-situ concentration monitoring device (not shown in the figure), a pH meter (not shown in the figure), and an analysis device (not shown in the figure); where:

[0128] The in-situ infrared thermal imager 71 is arranged outside the heat exchange device 76, and is used to collect the target infrared thermal image of the heat exchange device 76 and transmit the target infrared thermal image to an analysis device (not shown in the figure), so that the analysis device (not shown in the figure) can judge the pitting situation of the heat exchange device 76 according to the target infrared thermal image.

[0129] The pressure monitoring device 72 is arranged at the inlet of the heat exchange device 76, and is used to detect the real-time pressure value of the heat exchange device 76 and transmit the real-time pressure value to an analysis device (not shown in the figure), so that the analysis device (not shown in the figure) can judge whether pitting failure occurs in the heat exchange device 76 according to the real-time pressure value.

[0130] A weak magnetic detector 73 is arranged around a heat exchange device 76 to scan the area where the heat exchange device 76 is located, obtain weak magnetic monitoring data, and transmit the weak magnetic monitoring data to an analysis device (not shown in the figure) so that the analysis device (not shown in the figure) can analyze and obtain the position where pitting corrosion occurs on the heat exchange device 76 according to the weak magnetic monitoring data;

[0131] A constant current instrument 74 and a constant potential instrument 75 are connected to the heat exchange device 76 to apply a constant current or a constant voltage to the heat exchange device 76 to accelerate the corrosion rate of the heat exchange device 76 during the salt spray test;

[0132] An in-situ concentration monitoring device (not shown in the figure) is arranged inside the heat exchange device 76 to detect the ion concentration of the heat exchange device 76 and transmit the ion concentration to an analysis device (not shown in the figure) so that the analysis device (not shown in the figure) can judge the occurrence of pitting corrosion on the heat exchange device 76 according to the ion concentration;

[0133] A pH meter (not shown in the figure) is arranged inside the heat exchange device 76 to detect the pH value inside the heat exchange device 76 and transmit the pH value to an analysis device (not shown in the figure) so that the analysis device (not shown in the figure) can judge the occurrence of pitting corrosion on the heat exchange device 76 according to the pH value.

[0134] It should be understood that the specific embodiments described herein are only used to explain this application and not to limit it. According to the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0135] Obviously, the drawings are only some examples or embodiments of the present application. For those of ordinary skill in the art, the present application can also be applied to other similar situations according to these drawings without creative efforts. In addition, it can be understood that although the work done during the development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be regarded as insufficient disclosure of the present application.

[0136] The term "embodiment" in the present application means that the specific features, structures, or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification and does not necessarily mean the same embodiment, nor does it mean being independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0137] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0138] The above embodiments only represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for detecting pitting corrosion of a heat exchange device, characterized in that, include: During the salt spray test of the heat exchange device, obtaining a target infrared thermal image of the heat exchange device; Performing target area detection on the target infrared thermal image, and when the target area exists in the target infrared thermal image, determining the temperature difference between the target area and the surrounding area and the shape of the target area, wherein the target area includes a bright area and / or a dark area; According to the temperature difference and the shape of the target area, a target pitting result of the heat exchange device is analyzed and obtained.

2. The method for detecting pitting corrosion of a heat exchange device according to claim 1, characterized in that, The step of analyzing and obtaining a target pitting result of the heat exchange device according to the temperature difference and the shape of the target area includes: When the target area includes only bright areas, the temperature difference between the bright areas in the target infrared thermal image and the surrounding intact areas and the area shape of the bright areas in the target infrared thermal image are analyzed to obtain a first pitting corrosion result of the heat exchange device; the first pitting corrosion result is used as the target pitting corrosion result; When the target area includes only a dark area, analyzing the temperature difference between the dark area in the target infrared thermal image and the dark area in the surrounding intact area and the area shape of the dark area in the target infrared thermal image to obtain a second pitting result of the heat exchange device; and using the second pitting result as the target pitting result; When the target area includes a bright area and a dark area, the target pitting result is obtained by combining the first pitting result and the second pitting result.

3. The method for detecting pitting corrosion of a heat exchange device according to claim 1, characterized in that, The step of analyzing the temperature difference between the bright area in the target infrared thermal image and the bright area in the surrounding intact area and the area shape of the bright area in the target infrared thermal image to obtain the first pitting result of the heat exchange device includes: When the temperature difference of the bright area is within the preset first temperature difference range, if the shape of the bright area is a small dot, it is judged that the tube wall of the heat exchange device is thinned and the coating of the heat exchange device has pitting and cracking; When the temperature difference of the bright area is within the preset second temperature difference range, if the shape of the bright area is a concentric ring or an elliptical ring, it is determined that the tube wall of the heat exchange device is thinned and the pitting of the heat exchange device extends along the circumferential direction; When the temperature difference of the bright area is within the preset second temperature difference range, if the shape of the bright area is a small dot or irregular shape, it is judged that the tube wall of the heat exchange device is thinned, and the pitting of the heat exchange device extends along the wall; Wherein, the first temperature difference range is smaller than the second temperature difference range.

4. The method for detecting pitting corrosion of a heat exchange device according to claim 1, characterized in that, The step of analyzing the temperature difference between the dark area in the target infrared thermal image and the dark area in the surrounding intact area and the area shape of the dark area in the target infrared thermal image to obtain the second pitting result of the heat exchange device includes: When the temperature difference of the dark area is within a preset third temperature difference range, if the shape of the dark area is irregular, it is determined that the heat exchange device has impurity quality defects; When the temperature difference of the dark area is within a preset fourth temperature difference range, if the shape of the dark area is a circle or an ellipse, it is determined that bubbling occurs in the coating of the heat exchange device and bubbles occur in the internal pipeline of the heat exchange device; When the temperature difference in the dark area is within a preset fourth temperature difference range, if the shape of the dark area is small dot-shaped or irregular, it is determined that pitting corrosion failure occurs in the heat exchange device; Among them, the third temperature difference range is smaller than the fourth temperature difference range.

5. The method for detecting pitting corrosion of a heat exchange device according to claim 1, characterized in that, During the salt spray test on the heat exchange device, the method further includes: Performing real-time pressure detection on the heat exchange device in a sealed state at the pipeline outlet to obtain a real-time pressure value; Calculating the pressure difference between the real-time pressure value and the initial pressure value; the initial pressure value is obtained by the initial detection when the heat exchange device is completed with sealing; When the pressure difference reaches a preset pressure difference threshold, it is determined that pitting corrosion failure occurs in the heat exchange device, and a pitting corrosion failure warning message is sent.

6. The method for detecting pitting corrosion of a heat exchange device according to claim 5, characterized in that, The method further includes: Determining the leakage amount of the heat exchange device with pitting corrosion failure according to the pressure difference; Determining the service life of the heat exchange device according to the leakage amount.

7. The method for detecting pitting corrosion of a heat exchange device according to claim 1 or claim 5, characterized in that, During the salt spray test on the heat exchange device, the method further includes: Obtaining weak magnetic monitoring data in the area where the heat exchange device is located; Drawing a weak magnetic monitoring data curve graph according to the weak magnetic monitoring data; Determining the positions where pitting corrosion occurs in the heat exchange device as the positions where the peaks and valleys are located in the weak magnetic monitoring data curve graph.

8. The method for detecting pitting corrosion of a heat exchange device according to claim 1 or claim 5, characterized in that,During the salt spray test on the heat exchange device, the method further includes: Applying a constant current to the heat exchange device based on a galvanostat or applying a constant voltage to the heat exchange device based on a potentiostat to accelerate the corrosion rate of the heat exchange device during the salt spray test.

9. The pitting corrosion detection method for a heat exchange device according to claim 1 or claim 5, characterized in that, During the salt spray test on the heat exchange device, the method further includes: Judging whether pitting corrosion occurs in the heat exchange device according to the ion concentration of the heat exchange device detected by an in-situ concentration monitoring device connected to the inside of the heat exchange device; Or, Judging whether pitting corrosion occurs in the heat exchange device according to the pH value inside the heat exchange device detected by a pH meter connected to the inside of the heat exchange device.

10. A pitting corrosion detection device for a heat exchange device, applying the pitting corrosion detection method for a heat exchange device according to any one of claims 1 to 9, characterized in that, The pitting corrosion detection device for the heat exchange device includes: an in-situ infrared thermal imager, a pressure monitoring device, a weak magnetic detector, a galvanostat, a potentiostat, an in-situ concentration monitoring device, a pH meter, and an analysis device; among them: The in-situ infrared thermal imager is arranged outside the heat exchange device and is used to collect a target infrared thermal image of the heat exchange device, and transmit the target infrared thermal image to the analysis device, so that the analysis device judges the pitting corrosion situation of the heat exchange device according to the target infrared thermal image; The pressure monitoring device is arranged at the inlet of the heat exchange device and is used to detect the real-time pressure value of the heat exchange device, and transmit the real-time pressure value to the analysis device, so that the analysis device judges whether pitting corrosion failure occurs in the heat exchange device according to the real-time pressure value; The weak magnetic detector is arranged around the heat exchange device, and is used to scan the area where the heat exchange device is located to obtain weak magnetic monitoring data; and transmit the weak magnetic monitoring data to the analysis device, so that the analysis device analyzes the position where pitting corrosion occurs on the heat exchange device according to the weak magnetic monitoring data; The galvanostat and potentiostat are connected to the heat exchange device, and are used to apply a constant current or a constant voltage to the heat exchange device to accelerate the corrosion rate of the heat exchange device during the salt spray test; The in-situ concentration monitoring device is arranged inside the heat exchange device, and is used to detect the ion concentration of the heat exchange device and transmit the ion concentration to the analysis device, so that the analysis device judges the pitting corrosion situation of the heat exchange device according to the ion concentration; The pH meter is arranged inside the heat exchange device, and is used to detect the pH value inside the heat exchange device and transmit the pH value to the analysis device, so that the analysis device judges the pitting corrosion situation of the heat exchange device according to the pH value.

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