High temperature on-line monitoring sensitivity test method and system for ht700p pipeline

Abstract

The embodiment of the application discloses a high-temperature online monitoring sensitivity test method and system for HT700P pipelines. The method comprises the following steps: preparing a plurality of test samples, the plurality of test samples are made of HT700P material and have pre-prepared crack defects; configuring an electrode array for each test sample, the electrode array is installed on the corresponding test sample and measured by using a four-probe method configuration, each four-probe method configuration comprises two current electrodes and two voltage electrodes, and is used for realizing the separation of current injection and voltage measurement; sequentially placing the plurality of test samples in a high-temperature environment for online micro-resistance measurement, the temperature of the high-temperature environment is not lower than 650 DEG C, and the high-temperature environment is used for simulating the operating condition of a high-temperature steam pipeline; for each test sample, a constant current is applied through the corresponding electrode array, a corresponding voltage value is measured, and a micro-resistance value of the test sample is calculated; and based on a plurality of micro-resistance values and corresponding crack defect depths, the measurement sensitivity of the crack defect depth is analyzed.

Description

Technical Field

[0001] This application relates to the technical field of HT700P material applications, and in particular to a method and system for testing the sensitivity of high-temperature online monitoring of HT700P pipelines. Background Technology

[0002] In the field of in-service monitoring of high-temperature metal components, especially high-temperature steam pipelines above 650°C, existing non-destructive testing technologies mainly rely on traditional methods such as ultrasound and X-rays. These methods typically require shutting down the equipment, disassembling the insulation layer, and then conducting contact testing. The testing process cannot achieve continuous online monitoring, and frequent shutdowns can lead to significant economic losses.

[0003] Existing technologies have significant shortcomings and deficiencies. First, their offline, contact-based detection modes cannot meet the needs of long-term, real-time status monitoring of critical equipment, and are insufficient to capture the dynamic processes of crack initiation and propagation. More importantly, conventional electronic sensors and measurement methods cannot operate stably for extended periods in high-temperature environments above 650°C; devices are prone to failure due to high temperatures. This makes it difficult for most online monitoring technologies to be applied under such harsh conditions, creating an industry bottleneck.

[0004] Therefore, there is an urgent need in this field to develop an online monitoring technology applicable to high-temperature materials such as HT700P and capable of long-term stable operation in high-temperature steam pipeline environments above 650℃. To reliably apply this technology in engineering practice, a targeted sensitivity testing method is first required to verify the accuracy and reliability of the monitoring technology in measuring crack defects in HT700P materials, providing crucial data and technical support for subsequent field installation and application. Summary of the Invention

[0005] This application proposes a method and system for testing the sensitivity of high-temperature online monitoring of HT700P pipelines, in order to overcome the deficiencies of the prior art.

[0006] According to a first aspect of the embodiments of this application, a method for testing the sensitivity of high-temperature online monitoring of HT700P pipelines is provided, comprising: Multiple test specimens were prepared, the multiple test specimens being made of HT700P material and having pre-existing crack defects; An electrode array is configured for each test specimen. The electrode array is installed on the corresponding test specimen and is configured using a four-probe method for measurement. Each four-probe method configuration includes two current electrodes and two voltage electrodes to achieve separation of current injection and voltage measurement. The multiple test samples were placed in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of the high-temperature environment was not lower than 650°C, which was used to simulate the operating conditions of a high-temperature steam pipeline. For each test specimen, a constant current is applied through the corresponding electrode array, the corresponding voltage value is measured, and the microresistance value of the test specimen is calculated. Based on the aforementioned microresistance values ​​and corresponding crack depths, the measurement sensitivity of crack depth is analyzed, and the crack propagation rate is evaluated.

[0007] In some embodiments, the plurality of test specimens includes static specimens for sensitivity testing to simulate fixed crack defects and dynamic specimens for sensitivity testing to simulate crack propagation processes.

[0008] In some embodiments, the thickness of the static sample is 20 mm or 40 mm, and the dimensions are 310 mm × 72 mm or 310 mm × 145 mm. The method further includes: Prepare multiple static samples; The static sample is divided into sections and crack defects are set, wherein the sections include a crack-free region as an initial value and a plurality of machined groove regions with increasing depth and length.

[0009] In some embodiments, the crack depth of the static specimen ranges from 4 mm to 30 mm, and the crack length of the static specimen ranges from 20 mm to 80 mm. The setting of the crack defect includes: The crack defect is created by electrical discharge machining or mechanical processing.

[0010] In some embodiments, the electrode array is mounted by welding or clamping, and the electrodes of the electrode array are made of the same material or austenitic material. The configuration of the electrode array for each test sample includes: The electrode array is arranged in an array on the surface of each test specimen, and the crack defect is covered by the electrode array.

[0011] In some embodiments, the method further includes: When using the welding installation method, the electrode array is directly welded to the surface of the corresponding test sample; When using a clamp-type installation, the electrode array is held on the surface of the corresponding test sample by clamp fasteners.

[0012] In some embodiments, the measurement using a four-probe configuration includes: A constant current is injected into the current electrode and the potential difference is measured through the voltage electrode, wherein the input impedance of the voltage measurement circuit is configured to be higher than the target threshold to eliminate the influence of contact resistance on the micro-resistance value.

[0013] In some embodiments, the electrode array is made of a high-temperature resistant material; the measurement accuracy of the microresistance value is 10⁻⁶. -4 Ω to 10 - On the order of 2Ω, based on multiple microresistance values ​​and corresponding crack depths, the measurement sensitivity of crack depth is analyzed, and the crack propagation rate is evaluated, including: Based on the aforementioned micro-resistance values ​​and the correlation between resistance changes and crack depth in the corresponding crack defect depth, the measurement sensitivity of crack defect depth is calculated by matrix function deduction, and the crack propagation rate is evaluated.

[0014] In some embodiments, the method further includes: Based on the test results of the measurement sensitivity of the crack defect depth and the results of the evaluation of the crack propagation rate, the real-time online monitoring of the weld seam of the high-temperature steam pipeline is regulated and data support is provided for the actual equipment installation.

[0015] According to a second aspect of this application, a high-temperature online monitoring sensitivity testing system for HT700P pipelines is provided, comprising: The test specimen preparation module is used to prepare multiple test specimens, which are made of HT700P material and have pre-existing crack defects. An electrode array configuration module is used to configure an electrode array for each test sample. The electrode array is installed on the corresponding test sample and is configured using a four-probe method for measurement. Each four-probe method configuration includes two current electrodes and two voltage electrodes to achieve separation of current injection and voltage measurement. The high-temperature environment simulation module is used to place the multiple test samples in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of the high-temperature environment is not lower than 650°C, which is used to simulate the operating conditions of a high-temperature steam pipeline. The microresistance value determination module is used to apply a constant current through the corresponding electrode array for each test sample, measure the corresponding voltage value, and calculate the microresistance value of the test sample. The crack defect analysis module is used to analyze the measurement sensitivity of crack defect depth based on multiple microresistance values ​​and corresponding crack defect depths, and to evaluate the crack propagation rate.

[0016] The beneficial effects of the high-temperature online monitoring sensitivity testing method and system for HT700P pipelines in this application include at least the following: This application embodiment, by preparing various test specimens including static and dynamic specimens, can comprehensively simulate various defect morphologies of HT700P material that may occur in practical applications, ranging from fixed cracks to propagating cracks. This provides a solid material basis for subsequent systematic testing of the response sensitivity of NILM monitoring technology to different crack sizes, making the test results more representative. By adopting the four-probe method combined with reliable installation methods such as welding or clamping, the influence of the contact resistance between the electrode and the specimen on the measurement results can be effectively eliminated. This ensures stable and accurate measurement of the micro-resistance changes caused by cracks in the material itself under high-temperature conditions, providing a key technical guarantee for high-precision sensitivity testing. By sequentially testing the samples in a high-temperature environment of no less than 650°C, the actual operating conditions of the high-temperature steam pipeline where the HT700P material is located are directly simulated. This verifies the long-term stability and reliability of the electrode array and the entire measurement system under high temperatures, solving the industry problem of easy failure of electronic devices under high-temperature conditions and ensuring the guiding value of the test results for engineering practice. By applying current and measuring voltage independently for each sample and calculating its micro-resistance value, a quantitative characterization of each specific crack defect state is achieved, transforming abstract crack defects into accurately measurable micro-resistance data. This provides an accurate data foundation for establishing a quantitative correlation between crack depth and resistance change and analyzing measurement sensitivity. By comprehensively analyzing the micro-resistance values ​​of different samples and their corresponding known crack defect depths or propagation processes, the sensitivity and accuracy of NILM monitoring technology in measuring the crack depth of HT700P material can be quantitatively evaluated. The embodiments of this application provide crucial data support and reliability verification for the online monitoring of weld seams in actual high-temperature steam pipelines, thereby laying a solid foundation for equipment installation and condition assessment in subsequent engineering practices and avoiding economic losses caused by downtime for inspection. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of a high-temperature online monitoring sensitivity test method for an HT700P pipeline according to an embodiment of this application; Figure 2 This is a schematic diagram of the processing of a crack defect in a static test specimen with dimensions of 310×145×40mm (thickness δ40mm) according to an embodiment of this application. Figure 3 This is a schematic diagram of the first type of crack defect processing for a static test specimen with dimensions of 310×72×40mm (thickness δ40mm) according to an embodiment of this application. Figure 4 This is a schematic diagram of the processing of a second type of crack defect with a static test specimen size of 310×72×40mm (thickness δ40mm) according to an embodiment of this application. Figure 5This is a schematic diagram of the processing of a crack defect in a static test specimen with dimensions of 310×72×20mm (thickness δ20mm) according to an embodiment of this application. Figure 6 This is a schematic diagram of the processing of crack defects in a dynamic test specimen according to an embodiment of this application; Figure 7 This is a schematic diagram of the monitoring point installation for a static test specimen with dimensions of 310×145×40mm (thickness δ40mm) according to an embodiment of this application. Figure 8 This is a schematic diagram of the installation of the first monitoring point for a static test specimen with dimensions of 310×72×40mm (thickness δ40mm) according to an embodiment of this application. Figure 9 This is a schematic diagram of the installation of a second type of monitoring point for a static test specimen with dimensions of 310×72×40mm (thickness δ40mm) according to an embodiment of this application. Figure 10 This is a schematic diagram of the monitoring point installation for a static test specimen with dimensions of 310×72×20mm (thickness δ20mm) according to an embodiment of this application. Figure 11 This is a schematic diagram showing the position of the clamp-type installed electrode in an embodiment of this application; Figure 12 This is a schematic diagram of a tensile test of a dynamic test specimen according to an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the various embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and with various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this disclosure. The various embodiments can be combined with and referenced by each other without contradiction.

[0019] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed embodiments of the present application, but merely to illustrate selected embodiments of the present application. Other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are all within the scope of protection of the embodiments of the present application.

[0020] This application discloses a method and system for testing the sensitivity of high-temperature online monitoring of HT700P pipelines. The method is based on the system and aims to use NILM (non-invasive high-precision DC micro-resistance cloud measurement technology) to perform real-time online detection of cracks in metal components of high-temperature steam pipelines operating above 650 degrees Celsius on HT700 material (new material application).

[0021] See attached document Figure 1 As shown, the high-temperature online monitoring sensitivity test method for an HT700P pipeline includes the following steps 110-150.

[0022] Step 110: Prepare multiple test specimens made of HT700P material and with pre-existing crack defects.

[0023] For example, the plurality of test specimens includes a static specimen for sensitivity testing to simulate fixed crack defects and a dynamic specimen for sensitivity testing to simulate crack propagation process.

[0024] For example, the thickness of the static sample is 20 mm or 40 mm, and the size is 310 mm × 72 mm or 310 mm × 145 mm.

[0025] In some embodiments, the method further includes: preparing a plurality of the static specimens; partitioning the static specimens and incorporating crack defects. The partitioning includes a crack-free region serving as an initial value, and a plurality of machined groove regions with increasing depth and length.

[0026] For example, the crack depth of the static specimen ranges from 4 mm to 30 mm, and the crack length of the static specimen ranges from 20 mm to 80 mm.

[0027] In some embodiments, the setting of the crack defect includes: creating the crack defect by electrical discharge machining or machining.

[0028] Step 120: Configure an electrode array for each test specimen. The electrode array is installed on the corresponding test specimen and measured using the four-point probe method (also known as the four-point resistance method).

[0029] Each of these four-probe configurations includes two current electrodes and two voltage electrodes to separate current injection from voltage measurement.

[0030] In some embodiments, configuring an electrode array for each test specimen includes: arranging the electrode array in an array on the surface of each test specimen and covering the crack defect through the electrode array.

[0031] For example, the electrode array is installed by welding or clamping, and the electrodes of the electrode array are made of the same material or austenitic material.

[0032] In some embodiments, the method further includes: when using the welding type mounting, directly welding the electrode array to the surface of the corresponding test specimen; when using the clamp type mounting, clamping the electrode array to the surface of the corresponding test specimen using clamp fasteners.

[0033] In some implementations, the measurement is performed using a four-probe configuration, which includes injecting a constant current into the current electrode and measuring the potential difference through the voltage electrode. The input impedance of the voltage measurement circuit is configured to be higher than a target threshold to eliminate the influence of contact resistance on the micro-resistance value.

[0034] For example, the electrode array is made of a high-temperature resistant material.

[0035] Step 130: Place the multiple test samples in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of the high-temperature environment is not lower than 650°C, which is used to simulate the operating conditions of a high-temperature steam pipeline.

[0036] In this embodiment, multiple test samples with prepared and installed electrode arrays are sequentially placed in a high-temperature environment with a temperature not lower than 650°C. This high-temperature environment is used to simulate the high-temperature steam pipeline operating conditions of the actual application of HT700P material. Under these conditions, online micro-resistance measurement is performed to verify the long-term stability and reliability of the electrode array and measurement system under real working conditions.

[0037] Step 140: For each test sample, a constant current is applied through the corresponding electrode array, the corresponding voltage value is measured, and the microresistance value of the test sample is calculated.

[0038] For example, the measurement accuracy of this microresistance value is 10. -4 Ω to 10 - On the order of 2Ω.

[0039] For example, for each test sample, a constant current is applied through the corresponding electrode array, the corresponding voltage value is measured, and the microresistance value of the test sample is calculated. This includes: for each test sample, measurement is performed through its corresponding dedicated electrode array: first, a constant current is injected into the sample through two current electrodes in a four-probe configuration; then, the potential difference between them is measured using two voltage electrodes; finally, according to Ohm's law, the microresistance value of the sample in its current state is calculated from the measured voltage value and the injected current value, with a measurement accuracy of up to 10. -4 Ω to 10 - This allows for precise quantification of the resistance changes in materials caused by crack defects, reaching levels on the order of 2Ω.

[0040] Step 150: Based on multiple microresistance values ​​and corresponding crack defect depths, analyze the measurement sensitivity of crack defect depth and evaluate the crack propagation rate.

[0041] In some implementations, the method of analyzing the measurement sensitivity of crack defect depth and evaluating crack propagation rate based on multiple micro-resistance values ​​and corresponding crack defect depths includes: calculating the measurement sensitivity of crack defect depth by matrix function deduction based on the correlation between resistance change and crack depth in multiple micro-resistance values ​​and corresponding crack defect depths, and evaluating crack propagation rate.

[0042] In some embodiments, the method further includes: regulating the real-time online monitoring of high-temperature steam pipeline welds based on test results of the measurement sensitivity of the crack defect depth and the results of the assessment of crack propagation rate, and providing data support for actual equipment installation.

[0043] This application embodiment, by preparing various test specimens including static and dynamic specimens, can comprehensively simulate various defect morphologies of HT700P material that may occur in practical applications, ranging from fixed cracks to propagating cracks. This provides a solid material basis for subsequent systematic testing of the response sensitivity of NILM monitoring technology to different crack sizes, making the test results more representative. By adopting the four-probe method combined with reliable installation methods such as welding or clamping, the influence of the contact resistance between the electrode and the specimen on the measurement results can be effectively eliminated. This ensures stable and accurate measurement of the micro-resistance changes caused by cracks in the material itself under high-temperature conditions, providing a key technical guarantee for high-precision sensitivity testing. By sequentially testing the samples in a high-temperature environment of no less than 650°C, the actual operating conditions of the high-temperature steam pipeline where the HT700P material is located are directly simulated. This verifies the long-term stability and reliability of the electrode array and the entire measurement system under high temperatures, solving the industry problem of easy failure of electronic devices under high-temperature conditions and ensuring the guiding value of the test results for engineering practice. By applying current and measuring voltage independently for each sample and calculating its micro-resistance value, a quantitative characterization of each specific crack defect state is achieved, transforming abstract crack defects into accurately measurable micro-resistance data. This provides an accurate data foundation for establishing a quantitative correlation between crack depth and resistance change and analyzing measurement sensitivity. By comprehensively analyzing the micro-resistance values ​​of different samples and their corresponding known crack defect depths or propagation processes, the sensitivity and accuracy of NILM monitoring technology in measuring the crack depth of HT700P material can be quantitatively evaluated. The embodiments of this application provide crucial data support and reliability verification for the online monitoring of weld seams in actual high-temperature steam pipelines, thereby laying a solid foundation for equipment installation and condition assessment in subsequent engineering practices and avoiding economic losses caused by downtime for inspection.

[0044] See attached document Figure 2-12 The figure shows a specific implementation process of a high-temperature online monitoring sensitivity test method for an HT700P pipeline according to this application.

[0045] Specifically, the prepared test specimens (all made of HT700P material) include three static test specimens and one dynamic test specimen. The three static test specimens are divided into two categories with a thickness of δ40mm and a thickness of δ20mm, respectively: δ40mm thickness, static specimen size 310×145×40mm; δ40mm thickness, static specimen size 310×72×40mm; δ20mm thickness, static specimen size 310×72×20mm. The dynamic test specimen has a thickness of δ10mm and a dynamic specimen size of 120×36×10mm.

[0046] In some embodiments, the fabrication of static test specimens for online monitoring of crack defect depth includes: fabrication of static test specimens with a thickness of δ40mm for online monitoring of crack defect depth and fabrication of static test specimens with a thickness of δ20mm for online monitoring of crack defect depth.

[0047] For example, the fabrication process for a static specimen with a thickness of δ40mm for online monitoring of crack depth includes the following steps. (Refer to Appendix) Figure 2 As shown, a crack defect test specimen with dimensions of 310×145×40mm (thickness δ40mm) was fabricated. The location, length, and depth of the zones are as follows: Zone 1 has no cracks, representing the initial value; Zone 2 has a crack defect with a machining depth of 7mm and a length of 40mm; Zone 3 has a crack defect with a machining depth of 14mm and a length of 60mm; Zone 4 has a crack defect with a machining depth of 21mm and a length of 80mm. (See attached document.) Figure 3 As shown, a crack defect test specimen with dimensions of 310×72×40mm was fabricated. The location, length, and depth of the zones are as follows: Zone 1 has a crack defect with a machining depth of 5mm and a length of 72mm; Zone 2 has a crack defect with a machining depth of 10mm and a length of 72mm; Zone 3 has a crack defect with a machining depth of 15mm and a length of 72mm. (See attached document.) Figure 4 As shown, a crack defect test specimen with a sample size of 310×72×40mm was prepared. The location, length and depth of the partitions are as follows: Zone 1 has a crack defect with a machining depth of 20mm and a length of 72mm; Zone 2 has a crack defect with a machining depth of 25mm and a length of 72mm; Zone 3 has a crack defect with a machining depth of 30mm and a length of 72mm.

[0048] For example, the fabrication process for a static specimen with a thickness of δ20mm for online monitoring of crack depth includes the following steps. (Refer to Appendix) Figure 5 As shown, two crack defect test specimens with dimensions of 310×72×20mm were prepared. The location, length and depth of the zones are as follows: Zone 1 has no cracks, representing the initial value; Zone 2 has a crack defect with a depth of 4mm and a length of 20mm; Zone 3 has a crack defect with a depth of 8mm and a length of 30mm; Zone 4 has a crack defect with a depth of 12mm and a length of 40mm.

[0049] For example, fabricating a crack defect test specimen for dynamic testing includes fabricating two crack defect test templates with specimen dimensions of 120×36×10mm. The longitudinal section of the tip of the crack initiation notch (through-cut) is equidistant from the left and right end faces of the specimen. Preferably, a fixed clamping gauge is used with an integral or additional cutting edge. A crack propagation initiation groove is located in the middle of both sides of the specimen. The initiation notch is milled to a depth of 2mm and a length of 95mm. Two Φ8 through holes are included, with their centers 15mm from the edge. That is, as... Figure 6As shown, two rectangular plates, each 120mm long and 36mm wide, are made of HT700P material. An 8mm diameter through hole is machined on each side of the plate (10mm from the edge) to connect a tensioning device for applying load. A 15mm long through-cut notch is pre-drilled in the middle of the plate as the initial crack initiation point. Symmetrical 2mm deep and 100mm long sharp grooves are milled along this notch on both sides of the plate to guide the crack to propagate stably along a predetermined path, thus enabling dynamic testing of the relationship between crack propagation rate and monitoring sensitivity.

[0050] In some embodiments, the installation scheme for monitoring points on the test specimen includes: setting a static specimen thickness of δ40mm, a specimen size of 310×145×40mm, and an electrode experimental layout dividing the static welding electrode into four zones (see attached diagram). Figure 7 As shown), these are used for testing based on the size of the test specimen, the partitions, and the electrode size, respectively; the test specimen size is set to 310×72×40mm, and the electrodes are installed using a clamp-type mounting method, with the electrode installation layout divided into 3 zones (see attached). Figure 8 (As shown); the test sample size was set to 310×72×40mm, and the electrode installation layout was divided into 3 zones (see attached diagram). Figure 9-10 (As shown).

[0051] Subsequently, a static zoning test was performed on a 20mm thick static sample using clamp-mounted electrodes. The dimensions of the test sample, zoning, and electrode were as follows: 310×72×20mm, divided into four zones: Zone 1 was crack-free, representing the initial value; Zone 2 had an EDM groove 4mm deep and 20mm long; Zone 3 had an EDM groove 8mm deep and 30mm long; and Zone 4 had an EDM groove 12mm deep and 40mm long. (See attached document.) Figure 11 As shown, the target position for installing the clamp-type electrode is illustrated. In this embodiment, the electrode, fixed on the clamping bar, is brought into full contact with the specimen using a clamp clamp. A ceramic insulating end sleeve is used to insulate the electrode from the clamping bar before the measuring electrode is installed. The clamp-type electrode consists of an insulating high-temperature resistant ceramic sleeve ring, a 304 stainless steel electrode (stainless steel screws and nuts), a 304 stainless steel open spring washer, a cold-pressed terminal block, a 304 stainless steel enlarged and thickened circular flat washer, a pluggable terminal block, a 304 stainless steel flat bar, and a 304 stainless steel UC-type clamping clip.

[0052] See attached document Figure 12As shown, the dynamic tensile test of the weld electrode with a straight-through notch verifies that, based on precise micro-resistance measurement technology (micro-ohm level), when a crack propagates in metal, the current path narrows or becomes distorted, leading to an increase in resistance. As the crack continues to propagate, the impedance gradually increases. The monitoring system detects crack propagation by measuring the increase in resistance over time, thus converting crack propagation into corrosion rate or crack propagation rate. Therefore, crack propagation in metal (weld) can be monitored online by measuring changes in resistance.

[0053] This application's embodiments possess at least the following advantages in the field of NILM high-temperature online monitoring of crack defect depth measurement for HT700P materials: Sensitivity testing of HT700P materials allows for a better understanding of material characteristics, leading to more accurate data analysis in subsequent practical applications; customization based on the physical properties of HT700P materials ensures better adaptation to the overall testing scheme; the electrodes are made of the same material or austenitic materials, resulting in low cost and wide applicability; the measuring electrodes are easy to install, using welding or clamping to mount on the equipment surface; and the use of a four-probe method to measure material resistivity and sheet resistance achieves a design that separates current and voltage measurements. Two independent probes, one for current and one for voltage, are used to inject a constant current into the material and do not participate in voltage measurement. The contact resistance is isolated in the current loop. The other two probes, one for voltage, are used to measure the potential difference (V) between the two probes. Since the input impedance of the voltage measurement loop is extremely high (almost no current flows through it), the contact resistance between the voltage probes and the material has a negligible impact on the measurement results. This embodiment of the application can complete the entire cumbersome on-site operation process of HT700P material indoors, reducing the cost and time of subsequent debugging and installation. This embodiment of the application can accurately determine the testing accuracy and overall stability of HT700P material under NILM high-temperature online monitoring, and greatly improve the overall efficiency, save labor costs and time, and shorten the overall testing time. It has great advantages for large workpieces and equipment components, especially for dense and batch applications.

[0054] This application also discloses a high-temperature online monitoring sensitivity testing system for HT700P pipelines, including: a test sample preparation module, an electrode array configuration module, a high-temperature environment simulation module, a micro-resistance value determination module, and a crack defect analysis module.

[0055] The test specimen preparation module is used to prepare multiple test specimens made of HT700P material and with pre-existing crack defects.

[0056] The electrode array configuration module is used to configure an electrode array for each test specimen. The electrode array is installed on the corresponding test specimen and is configured using a four-probe method for measurement. Each four-probe method configuration includes two current electrodes and two voltage electrodes to achieve separation of current injection and voltage measurement.

[0057] The high-temperature environment simulation module is used to place multiple test samples in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of this high-temperature environment is not lower than 650℃, which is used to simulate the operating conditions of high-temperature steam pipelines.

[0058] The microresistance value determination module is used to apply a constant current through the corresponding electrode array for each test sample, measure the corresponding voltage value, and calculate the microresistance value of the test sample.

[0059] The crack defect analysis module is used to analyze the measurement sensitivity of crack defect depth based on multiple microresistance values ​​and corresponding crack defect depths, and to evaluate the crack propagation rate.

[0060] This application embodiment also installs array sensors on both sides of the weld. When a crack appears or propagates in the weld, it causes an increase in resistance. This provides a sensitivity testing system for measuring crack depth by calculating the crack depth through matrix functions and monitoring the crack propagation rate. This application embodiment also addresses the need for precise measurement of many weak signals (such as voltage, current, and resistance) in scientific research, measurement, and monitoring fields. Micro-resistance measurement is one of the more challenging aspects of weak DC signal detection, such as metal cracks, resistance during metal heat treatment, and changes in resistivity after metal welding, where the resistance value is in the range of 10 ohms. -4 -10 -2 Ω or even smaller. Therefore, the micro-resistance measurement of the embodiments of this application has very important practical significance in the fields of scientific research, measurement, and monitoring.

[0061] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this application, and this application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this application, and these modifications and improvements are also considered to represent the scope of protection of this application.

Claims

1. A method for testing the sensitivity of high-temperature online monitoring of HT700P pipelines, characterized in that, include: Multiple test specimens were prepared, the multiple test specimens being made of HT700P material and having pre-existing crack defects; An electrode array is configured for each test specimen. The electrode array is installed on the corresponding test specimen and is configured using a four-probe method for measurement. Each four-probe method configuration includes two current electrodes and two voltage electrodes to achieve separation of current injection and voltage measurement. The multiple test samples were placed in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of the high-temperature environment was not lower than 650°C, which was used to simulate the operating conditions of a high-temperature steam pipeline. For each test specimen, a constant current is applied through the corresponding electrode array, the corresponding voltage value is measured, and the microresistance value of the test specimen is calculated. Based on the aforementioned microresistance values ​​and corresponding crack depths, the measurement sensitivity of crack depth is analyzed, and the crack propagation rate is evaluated.

2. The method according to claim 1, characterized in that, The plurality of test specimens include static specimens for sensitivity testing to simulate fixed crack defects and dynamic specimens for sensitivity testing to simulate crack propagation processes.

3. The method according to claim 2, wherein the thickness of the static sample is 20 mm or 40 mm, and the dimensions are 310 mm × 72 mm or 310 mm × 145 mm, characterized in that, The method further includes: Prepare multiple static samples; The static sample is divided into sections and crack defects are set, wherein the sections include a crack-free region as an initial value and a plurality of machined groove regions with increasing depth and length.

4. The method according to claim 3, wherein the crack depth of the static specimen ranges from 4 mm to 30 mm, and the crack length of the static specimen ranges from 20 mm to 80 mm, characterized in that, The setting of crack defects includes: The crack defect is created by electrical discharge machining or mechanical processing.

5. The method according to claim 1, wherein the electrode array is installed by welding or clamping, and the electrodes of the electrode array are made of the same material or austenitic material, characterized in that, The configuration of an electrode array for each test sample includes: The electrode array is arranged in an array on the surface of each test specimen, and the crack defect is covered by the electrode array.

6. The method according to claim 5, characterized in that, The method further includes: When using the welding installation method, the electrode array is directly welded to the surface of the corresponding test sample; When using a clamp-type installation, the electrode array is held on the surface of the corresponding test sample by clamp fasteners.

7. The method according to claim 1, characterized in that, The measurement using a four-probe configuration includes: A constant current is injected into the current electrode and the potential difference is measured through the voltage electrode, wherein the input impedance of the voltage measurement circuit is configured to be higher than the target threshold to eliminate the influence of contact resistance on the micro-resistance value.

8. The method according to claim 1, wherein the electrode array is made of a high-temperature resistant material; and the measurement accuracy of the microresistance value is 10. -4 Ω to 10 - The value is on the order of 2Ω, and its characteristic is that... The method of analyzing the measurement sensitivity of crack defect depth and evaluating crack propagation rate based on multiple microresistance values ​​and corresponding crack defect depths includes: Based on the aforementioned micro-resistance values ​​and the correlation between resistance changes and crack depth in the corresponding crack defect depth, the measurement sensitivity of crack defect depth is calculated by matrix function deduction, and the crack propagation rate is evaluated.

9. The method according to claim 1, characterized in that, The method further includes: Based on the test results of the measurement sensitivity of the crack defect depth and the results of the evaluation of the crack propagation rate, the real-time online monitoring of the weld seam of the high-temperature steam pipeline is regulated and data support is provided for the actual equipment installation.

10. A high-temperature online monitoring sensitivity testing system for HT700P pipelines, characterized in that, include: The test specimen preparation module is used to prepare multiple test specimens, which are made of HT700P material and have pre-existing crack defects. An electrode array configuration module is used to configure an electrode array for each test sample. The electrode array is installed on the corresponding test sample and is configured using a four-probe method for measurement. Each four-probe method configuration includes two current electrodes and two voltage electrodes to achieve separation of current injection and voltage measurement. The high-temperature environment simulation module is used to place the multiple test samples in a high-temperature environment in sequence for online micro-resistance measurement. The temperature of the high-temperature environment is not lower than 650°C, which is used to simulate the operating conditions of a high-temperature steam pipeline. The microresistance value determination module is used to apply a constant current through the corresponding electrode array for each test sample, measure the corresponding voltage value, and calculate the microresistance value of the test sample. The crack defect analysis module is used to analyze the measurement sensitivity of crack defect depth based on multiple microresistance values ​​and corresponding crack defect depths, and to evaluate the crack propagation rate.

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