High-temperature galvanic corrosion testing system and testing method for external stress

Abstract

The invention discloses an external stress high-temperature galvanic corrosion test system and a test method, the system is equipped with a constant load stress ring, can apply a unidirectional tensile load to two metal pieces simultaneously or independently, and can realize a multi-combination stress corrosion and galvanic corrosion coupling corrosion test. Meanwhile, the stress ring system is provided with a load sensor and a load monitoring instrument, so that a load can be accurately applied to the sample, and the change of sample force in the test process can be monitored in real time. According to the system, the problem that existing galvanic corrosion and stress corrosion cannot be tested in a coupling mode is solved by additionally arranging the stress ring system in design, and due to the arrangement of the multifunctional portable measuring unit, the real-time monitoring function on the PH, dissolved oxygen and conductivity of a corrosive medium is achieved. Generally speaking, the system meets the diversified requirements of modern corrosion tests, and provides a scientific basis for selection of metal materials and equipment design in the working condition environment coupled with stress and complex corrosion media.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of galvanic corrosion testing devices, and particularly relates to a high-temperature galvanic corrosion testing system with external stress and a testing method. BACKGROUND

[0002] In the working environment of petroleum, chemical industry, nuclear power and the like, different metal materials are often applied to the same device and exposed to the same corrosion medium. When there is a potential difference between the two metal materials, galvanic corrosion occurs, which causes the metal with a negative potential (anode) to accelerate corrosion in the corrosion medium, while the metal with a positive potential (cathode) corrodes slowly, and the difference in corrosion rate between the two accelerates the damage of the device. At the same time, due to the complexity of the working environment, galvanic corrosion often coexists with stress corrosion, and the two synergize to accelerate the damage of the material and thus restrict the stability of the device, seriously endangering the production capacity of related industries and the safety of workers. In the existing patent technology, there are only galvanic corrosion devices and stress corrosion devices, and the synergistic effect of the two in corrosion damage is not considered. At the same time, temperature has a non-negligible effect on the corrosion of the material, and the corrosion process of the material is greatly promoted in a high-temperature environment. In addition, the double superposition of galvanic corrosion and stress corrosion and the complexity of the medium environment have an unimaginable impact on the corrosion behavior of the material.

[0003] Therefore, there is an urgent need for a device that can comprehensively consider various corrosion factors that the material is subjected to and closely approach the corrosion behavior under real working conditions. Although there are some high-temperature and high-pressure galvanic corrosion testing systems on the market, these systems generally have insufficient design flexibility, single function, insufficient simulation of real working conditions, and other problems, making it difficult to meet the growing needs of corrosion testing. The existing galvanic corrosion system cannot effectively monitor and quantitatively control other factors (pH, dissolved oxygen, conductivity) in the corrosion medium, which hinders the study of the influence of medium factors on galvanic corrosion. In addition, the current galvanic corrosion system does not have the function of applying external load, and it is difficult to test the coupling corrosion damage of stress corrosion and galvanic corrosion. At the same time, the existing stress corrosion system can only study the stress corrosion of a single material under different stress conditions, and the testing efficiency is low, and the application range is limited. SUMMARY

[0004] In order to truly reflect the synergistic corrosion effect of stress corrosion and galvanic corrosion on the material under the condition of external stress, the application provides a high-temperature galvanic corrosion testing system with external stress and a testing method. The system can not only simulate real corrosion medium and high-temperature environment, but also accurately measure and evaluate the galvanic corrosion behavior of different metal material combinations according to the real working conditions coupled with stress.

[0005] To this end, the application adopts the following technical solutions: A kind of high temperature galvanic corrosion test system of applied stress, including constant load stress ring, test pool, clamping body, multifunctional portable measuring unit; The constant load stress ring is vertically fixed on the stress ring base in ring structure, and the top and bottom of the constant load stress ring are connected with vertically arranged super nuts, which are upper and lower super nuts respectively, the two super nuts are opposite to each other, and the load is applied to the sample through the super nut;Load sensor is connected between super nut and constant load stress ring, and load sensor is used to measure the value of applied load; The test pool is located at the center of the constant load stress ring, and the outer wall of the test pool is provided with a heating unit for heating the test pool;The lower end of the upper super nut is connected to the test pool top cover and penetrates into the test pool, and the lower end of the upper super nut is tightly connected with the clamping body, so as to apply pulling force to the clamping body through the upper super nut;The test sample is vertically clamped on the clamping body, and the test pool bottom is fixedly connected with the stress ring through the lower super nut, to ensure the stability of the test pool during the experiment; A platinum electrode interface, a reference electrode interface, an oxygen removal exhaust valve and a backwater outlet are provided on the test pool top cover, and the backwater outlet pipeline is connected with the outlet of the multifunctional portable measuring unit;The test pool bottom is provided with an oxygen removal inlet valve, a water outlet and a temperature sensor, and the oxygen removal inlet valve is connected with an external nitrogen cylinder;The water outlet pipeline is connected with the backwater outlet of the multifunctional portable measuring unit; The multifunctional portable measuring unit includes temperature sensor, dissolved oxygen electrode, pH electrode and conductivity electrode, the temperature sensor is arranged in the test pool for measuring the liquid temperature in the test pool;The dissolved oxygen electrode, pH electrode and conductivity electrode are arranged on the body of the multifunctional portable measuring unit, and the dissolved oxygen electrode, pH electrode and conductivity electrode are used to measure the liquid flowing through the multifunctional portable measuring unit.

[0006] Further, the heating unit is further provided with a heat preservation sleeve outside, and the barrel is uniformly heated by the strip-shaped heating unit, and the heat preservation sleeve effectively reduces heat loss.

[0007] Further, the body of the multifunctional portable measuring unit is further provided with dissolved oxygen monitoring instrument, pH monitoring instrument, conductivity monitoring instrument and temperature control instrument.

[0008] A test method of a high temperature galvanic corrosion test system of applied stress, the test method comprising the following steps: 1) Sample and electrode installation Two different test samples are placed in the clamping body respectively, and the two test samples are separated by an insulating spacer;The clamping body with assembled sample is installed and fixed with the test pool and the constant load stress ring through the super nut; Inject the solution required for the test into the test cell; install the platinum electrode, reference electrode, and temperature sensor in sequence, then install the load sensor above the constant load stress ring, then use a small wrench to apply a load to the small bolts on the super nut until the load reaches the specified value and stop loading; 2) Deoxygenation operation Connect the test cell to the external nitrogen cylinder, then open the deoxygenation exhaust valve and the nitrogen cylinder in sequence, and pass pure nitrogen into the test cell, while opening the multifunctional portable measurement unit to circulate the solution between the dissolved oxygen electrode and the test cell; observe the dissolved oxygen monitoring instrument, and when the dissolved oxygen value is in the range of 3-4ppb, the experimental environment reaches an oxygen-free state; 3) Test preparation and start Immediately after completing the deoxygenation operation, close the deoxygenation exhaust valve and the nitrogen cylinder switch valve; connect the electrochemical electrode lines to the platinum electrode, reference electrode, and working electrode leads, and connect the GND line to the working electrode lead; then open the corresponding monitoring control instrument as needed, start the VersaStudio software, and conduct galvanic corrosion testing work.

[0009] Design principle of the application: In order to solve the problems in the prior art, the galvanic corrosion test system is improved and innovated in many aspects. First of all, the system is equipped with a constant load stress ring, which can apply a unidirectional tensile load to two metal pieces simultaneously or individually, and can realize stress corrosion and galvanic corrosion coupling corrosion test of multiple combinations. At the same time, the system is equipped with a load sensor and a load monitoring instrument, which can accurately apply a load to the sample and monitor the change of the force of the sample in real time during the test process.

[0010] Secondly, the test cell of the system is equipped with a heating temperature control device, which can realize temperature control from room temperature to 110℃ in the cell, and can meet the test of the influence of temperature on galvanic corrosion. At the same time, the test cell is connected to the nitrogen cylinder and the multifunctional portable measurement unit through the interface, which can realize the deoxygenation operation of the solution in the cell and the accurate monitoring of the corrosion medium (PH, dissolved oxygen, conductivity). Through the real-time monitoring function of these key parameters, the system can simulate variable corrosion environments and more accurately evaluate the influence of corrosion medium on the galvanic corrosion process between metals.

[0011] In addition, the system has a flexible clamp body, which not only supports galvanic corrosion testing of double samples, but also ensures electrochemical corrosion testing of single samples, greatly meeting the diversified testing needs. The clamp body and the sample are connected by ceramic pins to achieve insulation, and the distance between the two samples is adjusted by replacing insulating spacers of different thicknesses.

[0012] In summary, the system overcomes the problem of coupling test of existing galvanic corrosion and stress corrosion by increasing the stress ring system in the design, and realizes the real-time monitoring function of the corrosion medium PH, dissolved oxygen and conductivity by the configuration of multifunctional portable measurement unit. Overall, the system meets the diversified needs of modern corrosion test, and provides a scientific basis for the selection of metal materials and equipment design under the condition of coupling stress and complex corrosion medium environment.

[0013] The beneficial effects of the present application are: 1. Surpassing the traditional multi-application test requirements: The constant load stress ring is added to the traditional galvanic corrosion test system, which not only meets the test requirements of material galvanic corrosion and stress corrosion, but also realizes the test scene of coupling stress corrosion and galvanic corrosion. In addition, the stress ring system is equipped with a load sensor and a load monitoring instrument, which can accurately apply load to the sample and monitor the change of the force of the sample in real time during the test process.

[0014] 2. Surpassing the traditional temperature regulation function: The traditional high-temperature galvanic corrosion test system usually only has temperature regulation function and cannot handle other key factors in the corrosion solution. The innovation of our system is that not only can the temperature be accurately regulated, but also the pH value, conductivity and other parameters of the solution can be monitored and adjusted in real time, which fully improves the accuracy and reliability of the test.

[0015] 3. High-precision dissolved oxygen control and monitoring: In view of the influence of dissolved oxygen on galvanic corrosion, an external deoxidizing device and dissolved oxygen monitoring unit are designed, which can realize high-precision dissolved oxygen concentration detection of ±1ppb. This innovation can simulate the galvanic corrosion process under different dissolved oxygen environments, provide more accurate data support for galvanic corrosion research in high-temperature environment, and make up for the deficiency that the existing system cannot test under high-precision dissolved oxygen conditions.

[0016] 4. Flexible and diverse test sample clamps: The sample clamp design of traditional equipment is relatively single, and the flexible clamp design is adopted in the system, which supports double samples for galvanic corrosion test, stress corrosion test and coupling test of the two, and can also test the electrochemical corrosion behavior of each sample individually according to the needs. This design greatly improves the flexibility of the experiment and can meet different test requirements at the same time.

[0017] 5. Comprehensive corrosion environment evaluation capability: Compared with the traditional system which can only provide corrosion data under single temperature condition, our system has multi-factor coordinated control capability, which can perform galvanic corrosion test under high load, high temperature, different dissolved oxygen and different chemical environment, and provide more comprehensive and accurate evaluation for high-temperature galvanic corrosion, making up for the deficiency of existing equipment in adapting to complex corrosion environment.

[0018] In general, the innovation of the system lies in its comprehensive environmental monitoring capability and flexible experimental design, which breaks through the limitations of traditional simple high-temperature couple corrosion and stress corrosion test system, and can accurately evaluate the influence of galvanic corrosion, stress corrosion and coupling corrosion damage on metal materials in high temperature and complex corrosion medium, meeting the diversification and precision requirements of modern corrosion test. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the structural top view of the galvanic corrosion test system of the application; Figure 2 is the structural front view of the galvanic corrosion test system of the application; Figure 3 is the structural perspective view of the galvanic corrosion test system of the application; Figure 4 is the structural perspective view of the clamp body of the application; Figure 5 is the open circuit potential curve diagram of the example electrochemical test; Figure 6 is the curve diagram of the alternating current impedance of the example electrochemical test; Figure 7 is the dynamic potential polarization curve data diagram of the example electrochemical test; In the figure: 1-platinum electrode, 2-test cell, 3-test sample, 4-heat preservation cover, 5-temperature sensor, 6-first working test sample lead, 7-stress ring base, 8-second working test sample lead, 9-constant load stress ring, 10-reference electrode, 11-dissolved oxygen monitoring instrument, 12-pH monitoring instrument, 13-timer instrument, 14-load monitoring instrument, 15-conductivity monitoring instrument, 16-temperature control instrument, 17-dissolved oxygen electrode, 18-pH electrode, 19-conductivity electrode, 20-multifunctional portable measurement unit, 21-super nut, 22-oxygen removal exhaust valve, 23-load sensor, 24-nitrogen cylinder, 25-clamp body, 26-test sample insulation tube, 27-ceramic pin, 28-PEEK screw, 29-first working test sample, 30-second working test sample, 31-insulating spacer. DETAILED DESCRIPTION

[0020] The application will be further described below in combination with the drawings and specific embodiments: As Figure 1 described, the galvanic corrosion test system includes a constant load stress ring 9, a test cell 2, a clamp body 25, and a multifunctional portable measurement unit 20.

[0021] The constant load stress ring 9 is a ring structure vertically fixed on the stress ring base 7, and the stress ring base 7 is fixed on the workbench. The top and bottom of the constant load stress ring 9 are platform surfaces, and screw holes and through holes are formed on the platform surfaces. The super nuts 21 are arranged in the through holes. The top and bottom of the constant load stress ring 9 are connected with the super nuts 21, which are the upper super nut and the lower super nut. The two super nuts 21 are opposite to each other, and the super nuts 21 are used to apply load to the sample. The load sensor 23 is connected between the super nut 21 and the constant load stress ring 9, and the load sensor 23 is signal connected with the multifunctional portable measuring unit 20. The load monitoring instrument 14 can be used to monitor the change of the force value of the sample in real time.

[0022] The test cell 2 is located at the center of the constant load stress ring 9. The test cell 2 is made of high borosilicate glass material, has excellent corrosion resistance and high mechanical strength, and has a banded heating unit and a heat preservation sleeve 4 on the outer wall. The banded heating unit ensures uniform heating of the barrel, and the heat preservation sleeve 4 effectively reduces heat loss and provides safety protection. The lower end of the upper super nut 21 is connected with the top cover of the test cell 2 and penetrates into the test cell 2. The top cover of the test cell 2 is provided with a platinum electrode 1 interface, a reference electrode 10 interface, an oxygen removal exhaust valve 22 and a backwater outlet. The backwater outlet is provided with a tightly connected through hole rotary switch valve, which is connected with the water outlet of the multifunctional portable measuring unit 20 and extends to the test cell 2.

[0023] As shown in FIG. 1, the test cell 2 is located at the center of the constant load stress ring 9. The test cell 2 is made of high borosilicate glass material, has excellent corrosion resistance and high mechanical strength, and has a banded heating unit and a heat preservation sleeve 4 on the outer wall. The banded heating unit ensures uniform heating of the barrel, and the heat preservation sleeve 4 effectively reduces heat loss and provides safety protection. The lower end of the upper super nut 21 is connected with the top cover of the test cell 2 and penetrates into the test cell 2. The top cover of the test cell 2 is provided with a platinum electrode 1 interface, a reference electrode 10 interface, an oxygen removal exhaust valve 22 and a backwater outlet. The backwater outlet is provided with a tightly connected through hole rotary switch valve, which is connected with the water outlet of the multifunctional portable measuring unit 20 and extends to the test cell 2. Figure 4As shown, the upper super nut 21 inside the test pool 2 is tightly connected with the clamp body 25, and the pulling force is applied to the clamp body 25 through the upper super nut 21. The clamp body 25 has two grooves on the left and right inside, and the inside grooves are provided with sample insulation columns on both sides. The insulation columns are connected with the grooves in the form of insertion to prevent the sample from contacting the clamp body 25. Specifically, the insulation columns and the inside grooves of the clamp body 25 are partially embedded, and the other part is exposed, and there is a certain height difference between the insulation columns and the clamp body 25. The sample is placed between the upper and lower two insulation columns, thereby effectively preventing the sample from contacting the clamp and affecting the test results. The upper and lower ends of the sample are connected with the clamp body 25 through the ceramic pin 27. Specifically, the sample is placed between the four insulation columns inside the clamp body 25, and the left and right parts of the clamp are penetrated by the through hole. The sample has the same aperture through hole on the upper and lower sides, and the ceramic pin 27 is inserted from the right side of the clamp in sequence, penetrates the through hole of the sample, and penetrates the left side of the clamp, so as to realize the connection between the clamp and the sample, and ensure that the unidirectional tensile load can be stably applied to the sample. The two samples are adjusted in distance by placing the insulating spacer 31, and the upper and lower two PEEK screws 28 are fixed from the outside to the inside of the clamp body 25 to tightly fix the two samples. The PEEK screw 28 is screwed into the internal thread hole from the outside to the inside until it abuts against the sample. The four PEEK screws 28 abut against the sample at the same time to fix the sample and the insulating spacer 31 therebetween. The two samples are respectively a first working sample and a second working sample, and the first working sample and the second working sample are tightly connected with the first working sample lead 6 and the second working sample lead 8 respectively, and extend to the outside from the bottom of the test pool 2. The lower part of the test pool 2 is fixedly connected with the stress ring through the super nut 21, so as to ensure the stability of the test pool 2 during the experiment.

[0024] The bottom of the test pool 2 is provided with an oxygen removal inlet valve, a water outlet, and a temperature sensor 5. The oxygen removal inlet valve is connected with an external nitrogen cylinder 24. The water outlet joint is provided with a tightly connected through hole rotary on-off valve, which is connected with the water return port of the multifunctional portable measuring unit 20. The temperature sensor 5 is connected with the multifunctional portable measuring unit 20 through a transmission line, and displays the real-time temperature in the test pool 2 on the temperature control instrument 16. The multifunctional portable measuring unit 20 is provided with a dissolved oxygen electrode 17, a pH electrode, and a conductivity electrode, which are matched with the dissolved oxygen monitoring instrument 11, the pH monitoring instrument 12, and the conductivity monitoring instrument 15 to realize real-time monitoring of the dissolved oxygen value, pH, and conductivity of the corrosion solution during the test.

[0025] The experimental operation process is as follows: 1. Sample and electrode installation Two different test samples are placed in the grooves on both sides of the clamp body 25, and the two samples are separated by an insulating spacer 31 of appropriate width. By using spacers of different thicknesses, the effect of the galvanic couple spacing on galvanic corrosion can be studied. Then, the two samples are tightly connected to the clamp body 25 using ceramic pins 27, and the samples are placed between the four insulating columns inside the clamp body 25. The left and right parts of the clamp body 25 are connected by through holes, and the same diameter through holes are processed on the upper and lower sides of the samples. The ceramic pins 27 are inserted from the right side of the clamp body 25, through the through holes of the samples, and then through the left side of the clamp body 25, thereby achieving the through connection of the clamp body 25 and the samples. The PEEK screw 28 is used to fix the samples to the clamp body 25, limiting the left and right movement of the samples. The clamp body 25 with the assembled samples is fixed to the test tank 2 and the constant load stress ring 9 through the super nut 21. The required solution for the test is injected into the test tank 2 through the backwater inlet of the test tank 2 cover. The platinum electrode 1, the reference electrode 10, and the temperature sensor 5 are installed in sequence, and then the load sensor 23 is installed above the stress ring, and the load is applied to the six small bolts on the super nut 21 using a small wrench until the required load value is displayed on the load monitoring instrument 14.

[0026] 2. Deoxygenation operation The deoxygenation inlet valve is connected to the external nitrogen cylinder 24, and then the deoxygenation outlet valve 22 and the nitrogen cylinder 24 are opened in sequence to introduce pure nitrogen gas. At the same time, the multifunctional portable measurement unit 20 is turned on to allow the solution to flow between the dissolved oxygen electrode 17 and the test tank 2. The dissolved oxygen monitoring instrument 11 is observed, and when the dissolved oxygen value is in the range of about 3 ppb, the oxygen-free environment is achieved.

[0027] 3. Test preparation and start After the deoxygenation operation is completed, the deoxygenation outlet valve 22 and the nitrogen cylinder 24 are closed. The electrochemical electrode lines are connected to the platinum electrode 1, the reference electrode 10, and the working electrode lead, and the GND line is connected to the working electrode lead. Then, the corresponding monitoring control instruments are turned on as needed. If temperature testing is required, the temperature control instrument 16 is turned on and the target temperature is set. When the temperature in the test tank 2 stabilizes at the target temperature ±0.1℃, the VersaStudio software is started, and the galvanic corrosion test is carried out.

[0028] The above test operation process has given the detailed test process of the experimental group (external tensile force). The control group only needs to remove the applied tensile force operation, and the other operation processes are completely consistent.

[0029] Test detailed parameters: Temperature: 25℃ Load value: 300N Dissolved oxygen: 3ppb PH: 7.45 Data analysis: Figures 5 to 7 The data of open circuit potential, electrochemical impedance and potentiodynamic polarization curve of electrochemical test respectively. Open circuit potential is usually used to analyze the corrosion tendency of the material preliminarily, the more negative value indicates the greater corrosion tendency of the material. As shown in Figure 5 the open circuit potential of the material after applying 300N tensile load is negatively shifted by nearly 50mv, indicating that the corrosion tendency of the material after applying tensile load is significantly increased. Figure 6 Electrochemical impedance is used to study the charge transfer between the electrolyte interface and the material surface, which can directly indicate the corrosion resistance of the material surface. The greater the value, the stronger the corrosion resistance. Figure 6 The sample without tensile stress shows a larger impedance value, indicating that the tensile stress changes the charge transfer resistance of the sample surface, thereby reducing the corrosion resistance of the sample. From Figure 7 it can be directly observed that the sample with tensile stress shows lower corrosion potential and higher corrosion current density, indicating that the application of tensile stress promotes the corrosion of the sample.

Claims

1. A high-temperature galvanic corrosion testing system with applied stress, characterized in that: It includes a constant load stress ring (9), a test pool (2), a clamp body (25), and a multifunctional portable measuring unit (20); The constant load stress ring (9) is an annular structure vertically fixed on the stress ring base (7). The top and bottom of the constant load stress ring (9) are connected with vertically arranged super nuts (21), which are respectively an upper super nut and a lower super nut. The two super nuts (21) are opposite to each other up and down, and the load is applied to the sample through the super nuts (21); a load sensor (23) is connected between the super nut (21) and the constant load stress ring (9), and the load sensor (23) is used to measure the value of the applied load; The test pool (2) is located at the center of the constant load stress ring (9), and a heating unit is provided on the outer wall of the test pool (2), and the test pool (2) is heated by the heating unit; the lower end of the upper super nut is connected to the top cover of the test pool (2) and penetrates into the interior of the test pool (2), and the lower end of the upper super nut is tightly connected to the clamp body (25), and a pulling force is applied to the clamp body (25) through the upper super nut; the test sample is vertically clamped on the clamp body (25), and the bottom of the test pool (2) is fixedly connected to the stress ring through the lower super nut to ensure the stability of the test pool (2) during the experiment; The top cover of the test pool (2) is provided with a platinum electrode (1) interface, a reference electrode (10) interface, a deaeration exhaust valve (22) and a water return port, and the water return port pipe is connected to the water outlet of the multifunctional portable measuring unit (20); the bottom of the test pool (2) is provided with a deaeration air inlet valve, a water outlet, and a temperature sensor (5), and the deaeration air inlet valve is connected to an external nitrogen bottle (24); the water outlet pipe is connected to the water return port of the multifunctional portable measuring unit (20); The multifunctional portable measuring unit (20) comprises a temperature sensor (5), a dissolved oxygen electrode (17), a pH electrode, and a conductivity electrode (19). The temperature sensor (5) is arranged in the test pool (2) for measuring the temperature of the liquid in the test pool (2); the dissolved oxygen electrode (17), the pH electrode, and the conductivity electrode (19) are arranged on the body of the multifunctional portable measuring unit (20). The dissolved oxygen electrode (17), the pH electrode, and the conductivity electrode (19) are used to measure the liquid flowing through the multifunctional portable measuring unit (20).

2. The high-temperature galvanic corrosion testing system with applied stress according to claim 1, characterized in that: A heat-insulating sleeve (4) is further provided on the outside of the heating unit, and the strip-shaped heating unit ensures uniform heating of the barrel body, while the heat-insulating sleeve (4) effectively reduces heat loss.

3. The high-temperature galvanic corrosion testing system with applied stress according to claim 1, characterized in that: The multifunctional portable measuring unit (20) is further provided with a dissolved oxygen monitoring instrument (11), a pH monitoring instrument (12), a conductivity monitoring instrument (15) and a temperature control instrument (16).

4. A testing method for a high-temperature galvanic corrosion testing system with applied stress according to any one of claims 1 to 3, characterized in that: The test method includes the following steps: 1) Sample and electrode installation Two different test specimens are placed in the clamp body (25) respectively, and the two test specimens are separated by an insulating spacer; the clamp body (25) with the assembled specimens is fixed to the test cell (2) and the constant load stress ring (9) through the super nut (21); The solution required for the test is injected into the test pool (2); the platinum electrode (1), the reference electrode (10), and the temperature sensor (5) are installed in sequence, and then the load sensor (23) is installed above the constant load stress ring (9). Then, a small wrench is used to apply a load to the small bolt on the super nut (21) until the load reaches the value and the loading is stopped; 2) Deoxygenation operation Connect the test pool (2) to the external nitrogen bottle (24), then open the deoxygenation exhaust valve (22) and the nitrogen bottle (24) in sequence, and introduce pure nitrogen into the test pool (2). At the same time, open the multifunctional portable measuring unit (20) to allow the solution to flow between the dissolved oxygen electrode (17) and the test pool (2); observe the dissolved oxygen monitoring instrument (11). When the dissolved oxygen value is in the range of 3-4 ppb, the experimental environment reaches an oxygen-free state; 3) Test preparation and start-up After the deoxygenation operation is completed, immediately close the deoxygenation exhaust valve (22) and the nitrogen bottle (24) switch valve; connect the electrochemical electrode wires to the platinum electrode (1), reference electrode (10), and working electrode lead, and connect the GND wire to the working electrode lead; then open the corresponding monitoring and control instruments as needed, start the VersaStudio software, and carry out the galvanic corrosion test.

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