A kind of micro-tribological wear test device of cladding tube in oxygen-controlled liquid lead-bismuth environment

Abstract

This invention relates to the field of fretting corrosion and wear testing of high-temperature materials, specifically a fretting wear testing device for a clad tube in a controlled-oxygen liquid lead-bismuth environment. The device comprises a storage vessel and a test vessel fixed on a platform. The test vessel has a lid with an outlet pipe and an inlet pipe connected to a gas control circuit. The storage vessel has a lid with an outlet pipe and an inlet pipe connected to a gas control circuit. The bottom of the inner cavities of the storage and test vessels are connected by a connecting pipe with a control valve. A fretting wear testing component is installed inside the test vessel, and heaters are installed on the outer sides of both the storage and test vessels. This invention can precisely control the temperature, fretting wear rate (displacement control or load control), dissolved oxygen concentration, and other test parameters of the liquid lead-bismuth alloy, evaluating the fretting wear behavior of metallic materials in a controlled-oxygen high-temperature liquid lead-bismuth environment.

Description

Technical Field

[0001] This utility model relates to the field of fretting corrosion and wear testing of high-temperature materials, specifically a fretting wear testing device for cladding tubes in an oxygen-controlled liquid lead-bismuth environment. It is used to conduct fretting corrosion tests on cladding tubes in a liquid lead-bismuth environment with controllable oxygen content, and to evaluate the fretting corrosion performance of fuel cladding materials in a liquid lead-bismuth environment. Background Technology

[0002] Fuel cladding is a critical component of lead-cooled fast reactors. As the primary barrier between liquid lead-bismuth eutectic and nuclear fuel, its structural integrity plays a crucial role in the reactor's safety and stable operation. During service, the cladding tubes are exposed to high-temperature, controllable-oxygen liquid lead-bismuth eutectic coolant for extended periods. Under complex mechanical loads and fluid-induced vibrations, they not only face high-temperature corrosion and oxidative erosion but are also prone to fretting—the interaction of wear and corrosion caused by minute vibrations between relatively rubbing surfaces. This fretting corrosion can induce fretting corrosion and even failure of the cladding tubes. This fretting corrosion behavior is one of the main factors leading to shortened service life of the cladding tubes and system safety hazards. Therefore, accurate and quantitative simulation and evaluation of its corrosion-wear coupling effect are of great significance for the selection of materials, structural optimization, and life assessment of advanced nuclear energy devices.

[0003] Due to the physicochemical properties of lead-bismuth eutectic, liquid lead-bismuth under high-temperature conditions not only suffers from easy solidification and requires extremely precise control of temperature and oxygen content, but its excellent fluidity and corrosiveness also present engineering challenges such as sealing and safety for testing equipment. Furthermore, conventional fretting corrosion equipment lacks precise control and real-time monitoring of oxygen content and is not suitable for liquid metal environments. Existing high-temperature liquid lead-bismuth environment fretting corrosion testing equipment suffers from problems such as unstable loading methods, force loss and fluctuations, and inadequate sample positioning and fixture structures for the liquid metal environment, making it difficult for test results to accurately reflect the actual service performance of the cladding tube.

[0004] The patent with publication number CN117805006A proposes a corrosion testing device and method for liquid lead-bismuth materials. It solves the problems of oxygen concentration and temperature deviation caused by opening the cover for sampling through a lifting mechanism and a barrier mechanism. However, it can only carry out static corrosion tests and lacks fretting wear test components. It has neither tangential motion components (such as loading motor and loading shaft) nor can it apply normal load and tangential fretting displacement to the sample. It cannot simulate the corrosion-wear coupling effect caused by flow-induced vibration of the cladding tube during service. It can only evaluate the static corrosion performance of the material and cannot fully reflect the actual failure mechanism of the cladding tube. The patent with publication number CN104142281A proposes a tangential fretting wear test device driven by a voice coil motor. Although it can achieve tangential fretting reciprocating motion through a voice coil linear motor and adjust the temperature of the test medium with the help of a temperature control console, it is only designed for ordinary environmental media and cannot adapt to the physicochemical characteristics of lead-bismuth, which is easy to solidify and highly corrosive. It cannot simulate the service environment of lead-cooled fast reactor cladding tubes. It has neither dissolved oxygen detection elements nor gas control loops, so it cannot achieve real-time monitoring and precise adjustment of oxygen content in liquid lead-bismuth. It cannot meet the test requirements of cladding tubes in a liquid lead-bismuth environment with controllable oxygen content. It can only carry out fretting wear tests in conventional environments, which is out of touch with the special test scenarios of nuclear reactor materials. The patent with publication number CN109238889A proposes a fretting wear test device and system. The fretting wear test device is designed for sodium cold reactor environment and adopts a lever loading method to avoid loading failure under high corrosion environment. However, the test environment is liquid sodium. Liquid sodium and liquid lead bismuth have significant differences in melting point, corrosiveness and fluidity (for example, the melting point of lead bismuth is about 125°C and its corrosiveness is stronger at high temperature). Its device structure (such as sealing method and material selection) cannot be adapted to liquid lead bismuth and is prone to solidification blockage or excessive corrosion problems. Utility Model Content

[0005] The purpose of this invention is to provide a fretting wear test device for clad tubes in an oxygen-controlled liquid lead-bismuth environment. This device enables fretting wear testing of clad tubes in a controlled oxidation liquid lead-bismuth environment and can be used for high-temperature oxygen content-controlled liquid lead-bismuth environment, precise application of fretting loads, and research on corrosion-wear coupling behavior.

[0006] The technical solution of this utility model is:

[0007] A fretting wear test device for a casing tube in an oxygen-controlled liquid lead-bismuth environment includes a storage vessel and a test vessel fixed on a platform. The test vessel has a lid with a gas outlet and a gas inlet connected to a gas control circuit. The storage vessel has a lid with a gas outlet and a gas inlet connected to a gas control circuit. The gas control circuit controls the deoxygenation and oxygen content of the liquid lead-bismuth. The bottom of the inner cavities of the storage and test vessels are connected by a connecting pipe with a control valve to achieve liquid... The lead-bismuth system employs continuous circulation flow control. Through the inlet pipes of the test vessel, storage vessel, and test vessel, the liquid lead-bismuth in the test vessel and storage vessel is replaced and environmental parameters are adjusted, with precise control over oxygen content. The test vessel is equipped with a fretting wear testing assembly, which includes a tangential loading mechanism and a normal loading mechanism. These mechanisms work together to construct the mechanical load environment of the cladding tube during actual service. Heaters are installed on the outer sides of the storage vessel and test vessel, and these heaters are covered with an insulation layer.

[0008] The aforementioned fretting wear test device for the cladding tube in an oxygen-controlled liquid lead-bismuth environment includes a lid lifter on a platform. The lid lifter comprises a bracket, a lifting component, and an electric push rod. The bracket is mounted on the platform, and a vertical electric push rod is installed on the bracket. The lower end of the electric push rod is equipped with a lifting component. The lid lifter is connected to the test lid and the storage lid via the lifting component through threads. The lifting of the electric push rod is controlled by a button switch, which drives the lifting component to pull the test lid and the storage lid, thereby opening and closing the test lid and the storage lid.

[0009] The aforementioned fretting wear test device for the cladding tube in an oxygen-controlled liquid lead-bismuth environment includes a gas control circuit connected to an oxygen-controlled mixed gas cylinder via a pipeline. An oxygen-controlled solenoid valve is installed on the pipeline connecting the oxygen-controlled mixed gas cylinder and the gas control circuit. A dissolved oxygen electrode is installed inside the test vessel, and the dissolved oxygen electrode is connected to the oxygen-controlled solenoid valve via a circuit. An oxygen control system is installed on the circuit connecting the dissolved oxygen electrode and the oxygen-controlled solenoid valve. The oxygen-controlled mixed gas cylinder is a cylinder containing a mixture of argon and oxygen, or the oxygen-controlled mixed gas cylinder includes both an argon cylinder and an oxygen cylinder.

[0010] The aforementioned fretting wear test device for cladding tubes in an oxygen-controlled liquid lead-bismuth environment includes a tangential loading mechanism comprising a motor, a tangential loading coupling, and a bellows. The specific structure is as follows: one end of the tangential loading coupling passes through the wall of the test vessel and is sealed by the bellows, and is connected to the motor output. Two lateral flanges are provided on the outer wall of the test vessel, with a bellows at one end of each flange. The tangential loading coupling passes through both the lateral flanges and the bellows. A flange connected to the end face of the bellows is provided on the tangential loading coupling, allowing for micron-level displacement loading. A sample stage is positioned in the middle of the tangential loading coupling within the test vessel. A lower sample clamp is installed on the sample stage. The lower sample of the friction pair is fixed to the sample stage by the lower sample clamp, which is adjusted and fixed by a vertical adjusting screw, achieving reliable loading and friction pair engagement of the cladding tube sample.

[0011] The aforementioned fretting wear test device for the cladding tube in an oxygen-controlled liquid lead-bismuth environment has a structure in which the upper and lower samples are arranged opposite each other, with the upper sample being a cylindrical sample and the lower sample being a plate-shaped sample; the input end of the motor is connected to the process monitoring controller.

[0012] The aforementioned fretting wear test device for the cladding tube in an oxygen-controlled liquid lead-bismuth environment includes a normal loading mechanism comprising a loading bolt, a load sensor, a bellows, a normal loading coupling, and a loading coupling support assembly. The specific structure is as follows: one end of the normal loading coupling passes through the test vessel lid and extends into the test vessel, connecting to one end of a vertical upper sample clamp. The other end of the upper sample clamp is connected to the upper sample of the friction pair via an upper sample clamp. A loading coupling support assembly is installed on the test vessel lid. The other end of the normal loading coupling is sequentially connected to the load sensor and the loading bolt. The normal loading coupling, load sensor, and loading bolt are integrally inserted and installed on the loading coupling support assembly. The portion of the normal loading coupling outside the test vessel is fitted with a bellows. The normal loading mechanism applies a load to the load sensor by rotating the loading bolt, and the normal load is applied through the normal loading coupling passing through the test vessel lid and the bellows.

[0013] The aforementioned fretting wear test device for the cladding tube in an oxygen-controlled liquid lead-bismuth environment includes an upper sample clamp and a lower sample clamp for the friction pair. One end of the upper sample clamp is fitted with an upper sample chuck. The lower sample clamp is equipped with a vertical adjustment screw, a lower base, a lower sample chuck, and a wedge. The lower sample is placed on the lower base of the clamp. A wedge is placed on the top of the lower sample. Lower sample chucks are symmetrically arranged on both sides of the wedge. The lower sample chucks are connected to the lower base of the clamp via the vertical adjustment screw. The lower sample chucks and the wedges are engaged by inclined surface contact.

[0014] The design concept of this utility model is:

[0015] This utility model device includes a fretting wear test assembly, a test vessel, a storage vessel, a heater, a conductive pipe, a valve, a stand, and a gas control circuit. The fretting wear test assembly includes a tangential loading mechanism and a normal loading mechanism. The tangential loading mechanism includes a motor, a loading shaft, a loading shaft support assembly, and a bellows. The normal loading mechanism includes a loading bolt, a load sensor, a loading shaft, a loading shaft support assembly, and a bellows. The test vessel and the storage vessel are respectively equipped with a test vessel cover and a storage vessel cover. The gas control circuit includes a dissolved oxygen electrode, an oxygen control solenoid valve, and an oxygen control mixed gas cylinder. When the temperature of the conducting tube is greater than 250℃, high-purity argon or high-purity nitrogen is introduced into the inlet pipe of the storage vessel to allow the liquid lead-bismuth alloy in the storage vessel to flow into the test vessel. High-purity argon or high-purity nitrogen is introduced into the inlet pipe of the test vessel to allow the liquid lead-bismuth alloy in the test vessel to flow into the storage vessel. The load is applied to the load sensor by rotating the loading bolt of the normal loading mechanism. The load is applied through the loading coupling through the test vessel cover and through the bellows to achieve normal load loading. The motor outputs the set amplitude, which passes through the test vessel body through the loading coupling and through the bellows to achieve tangential micro-motion behavior. Micro-motion wear tests with different combinations of normal load and amplitude can be realized.

[0016] This invention focuses on simulating the real service environment of cladding tubes and improving test safety and stability. It employs a micro-motion wear test component, a dual-reactor independent interconnection structure, and a gas control loop design. This integrates tangential / normal micro-motion loading, liquid lead-bismuth temperature control, and real-time oxygen content regulation to ensure the test environment matches the service environment of the cladding tubes. Based on the principle of communicating vessels, the test vessel and storage vessel are designed. The storage vessel independently handles lead-bismuth melting and pre-deoxygenation, using high-purity argon pressure to transfer liquid lead-bismuth to the test vessel, enabling sample loading and unloading at room temperature and avoiding contact with high-temperature steam. A sunken clamp structure lowers the sample clamp position below the drive shaft level, ensuring the sample is completely immersed in liquid lead-bismuth while preventing contact between the loading shaft and the lead-bismuth, thus preventing adhesion and corrosion. The optimized tangential loading structure uses motor loading combined with bellows sealing and support components to solve the problem of long-term operational leakage, ensuring stable operation for 15 days at 20Hz and improving the reliability of test data. This invention can precisely control the temperature, fretting wear rate (displacement control or load control), dissolved oxygen concentration and other test parameters of liquid lead-bismuth alloy, and evaluate the fretting wear behavior of metallic materials in a high-temperature liquid lead-bismuth environment with controllable oxygen content.

[0017] The advantages and beneficial effects of this utility model are:

[0018] 1. This utility model provides a fretting wear test device for cladding tubes in an oxygen-controlled liquid lead-bismuth environment. It can carry out fretting wear tests on actual fuel cladding tubes in liquid lead-bismuth environment, and record and collect test parameters such as temperature, dissolved oxygen concentration, displacement, and wear amount in real time to evaluate its fretting wear test performance in liquid lead-bismuth environment.

[0019] 2. The device of this utility model connects the tensile vessel and the storage vessel through a conductive pipe, realizing the transfer of high-temperature liquid lead bismuth between the test vessel and the storage vessel. It is convenient to load and unload the sample of the test vessel in room temperature air. The operation is simple and convenient and does not come into contact with lead bismuth vapor.

[0020] 3. The tangential force of this utility model device is applied by a motor, which can achieve stable operation for 15 days at a frequency of 20Hz, thus solving the problem of force leakage that occurs as the equipment operates.

[0021] 4. The device of this utility model adopts a sunken structure for the internal clamp of the test vessel, which extends the position of the sample clamp to a position lower than the horizontal plane of the drive shaft. The sample clamp can be completely submerged within the lead-bismuth liquid level in the vessel, and the loading coupling will not come into contact with the lead-bismuth.

[0022] 5. The experimental vessel and storage vessel of this utility model are designed to be independent and interconnected. The experimental vessel is equipped with a clamp and a loading shaft. There is no space for solid lead bismuth to melt inside it. By making the storage vessel independent of the main experimental body, the problem of solid lead bismuth melting is cleverly solved. In addition, the storage vessel can also be pre-deoxygenated. The liquid lead bismuth after pre-deoxygenation can reduce the corrosion of the components inside the vessel when it enters the experimental vessel. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the fretting wear test device in a liquid lead-bismuth environment with controllable oxygen content in the cladding tube according to this utility model.

[0024] Figure 2 This is a schematic diagram of the upper and lower sample clamps of the friction pair in the fretting wear test device for a liquid lead-bismuth environment with controllable oxygen content in the cladding tube of this utility model.

[0025] Figure 3 This is a schematic diagram of the tangential loading mechanism of this utility model.

[0026] Figure 4 This is a schematic diagram of the normal loading mechanism of this utility model.

[0027] In the diagram: 1. Storage vessel lid; 2. Storage vessel outlet pipe; 3. Storage vessel; 4. Control valve; 5. Motor; 6. Process monitoring controller; 7. Display; 8. Test vessel inlet pipe; 9. Normal loading mechanism; 10. Test vessel outlet pipe; 11. Dissolved oxygen electrode; 12. Oxygen control solenoid valve; 13. Oxygen control mixed gas cylinder; 14. Oxygen control system; 15. Test vessel; 16. Tangential loading coupling; 17. Test vessel lid; 18. Conductor pipe; 19. Stand; 20. Lid lifting mechanism; 21. Upper sample clamp; 22. Vertical adjusting screw ; 23 Lower sample clamp; 24 Upper sample; 25 Lower sample; 26 Side flange; 27 Bellows; 28 Flange; 29 Tangential loading mechanism; 30 Loading bolt; 31 Load sensor; 32 Bellows; 33 Normal loading coupling; 34 Loading coupling support assembly; 35 Bracket; 36 Lifting component; 37 Electric push rod; 38 Gas control circuit; 39 Sample stage; 40 Storage vessel inlet pipe; 41 Lower base of clamp; 42 Lower sample clamp; 43 Upper sample clamp; 44 Wedge block. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example

[0030] See Figures 1-4 This utility model proposes a fretting wear test device for a clad tube in an oxygen-controlled liquid lead-bismuth environment. It mainly includes a fretting wear test assembly, a storage vessel 3, a test vessel 15, a connecting pipe 18, a stand 19, and a vessel lid lifting mechanism 20. The specific structure is as follows:

[0031] Storage vessel 3 and test vessel 15 are fixed on the frame 19. Test vessel 15 is equipped with a test vessel cover 17, which has a test vessel outlet pipe 10 and a test vessel inlet pipe 8 connected to the gas control circuit 38. Storage vessel 3 is equipped with a storage vessel cover 1, which has a storage vessel outlet pipe 2 and a storage vessel inlet pipe 40 connected to the gas control circuit 38. The gas control circuit 38 is used for deoxygenation and oxygen content control of liquid lead-bismuth. The bottom of the inner cavity of storage vessel 3 and test vessel 15 are connected by a guide pipe 18, which is equipped with a control valve 4. This allows for continuous circulation control of liquid lead-bismuth. Through the test vessel inlet pipe 8, storage vessel inlet pipe 40, storage vessel outlet pipe 2, and test vessel outlet pipe 10, the liquid lead-bismuth in test vessel 15 and storage vessel 3 can be replaced and environmental parameters can be adjusted, facilitating precise control of oxygen content. The height design between the storage vessel 3 and the test vessel 15 is based on the principle of communicating vessels. Under normal pressure, the liquid inside the test vessel 15 flows completely back to the storage vessel 3 through the connecting pipe 18. In addition, heaters can be installed on the outside of the bodies of the storage vessel 3 and the test vessel 15, and the heaters are covered with an insulation layer.

[0032] The platform 19 is equipped with a lid lifting mechanism 20, which includes a bracket 35, a lifting component 36, an electric push rod 37, etc. The bracket 35 is set on the platform 19, and the electric push rod 37 is installed on the bracket 35 in a vertical direction. The lifting component 36 is installed at the lower end of the electric push rod 37. The lid lifting mechanism 20 can be connected to the test lid 17 and the storage lid 1 respectively through the lifting component 36 via threads. The lifting and lowering of the electric push rod 37 is controlled by a button switch to drive the lifting component 36 to pull the test lid 17 and the storage lid 1, thereby realizing the opening and closing of the test lid 17 and the storage lid 1.

[0033] An oxygen-controlled mixed gas cylinder 13 is connected to a gas control circuit 38 via a pipeline. An oxygen-controlled solenoid valve 12 is installed on the pipeline connecting the oxygen-controlled mixed gas cylinder 13 and the gas control circuit 38. A dissolved oxygen electrode 11 is installed inside the test vessel 15. The dissolved oxygen electrode 11 is connected to the oxygen-controlled solenoid valve 12 via a circuit. An oxygen control system 14 is installed on the circuit connecting the dissolved oxygen electrode 11 and the oxygen-controlled solenoid valve 12. The oxygen-controlled mixed gas cylinder 13 is a cylinder containing a mixture of argon and oxygen, or the oxygen-controlled mixed gas cylinder 13 includes both an argon cylinder and an oxygen cylinder.

[0034] During use, the device is equipped with a gas control circuit 38, which can be connected to the inner cavity of the test vessel 15 and the storage vessel 3 through pipelines. This allows for real-time adjustment and monitoring of the oxygen content in the liquid lead-bismuth environment, enabling precise control of oxygen removal and constant oxygen levels. It is suitable for simulated environments with different experimental requirements.

[0035] The test vessel 15 is equipped with a fretting wear test assembly, including a tangential loading mechanism 29 and a normal loading mechanism 9. The tangential loading mechanism and the normal loading mechanism respectively simulate the functions of flow-induced vibration fretting and simulate contact pressure. The two work together to construct the mechanical load environment of the cladding tube during actual service. Specifically, the tangential loading mechanism realizes fretting wear by applying small-amplitude, high-frequency tangential reciprocating motion to the sample to simulate the flow-induced vibration of the cladding tube caused by coolant flow in the reactor. The normal loading mechanism simulates the contact pressure between the cladding tube and the anti-vibration strip and support structure by applying a stable normal normal pressure to the anti-vibration pair sample.

[0036] The tangential loading mechanism 29 includes a motor 5, a tangential loading coupling 16, and a bellows 27. Its specific structure is as follows: one end of the tangential loading coupling 16 passes through the wall of the test vessel 15 and is sealed by the bellows 27, and is connected to the output end of the motor 5. The outer wall of the test vessel 15 is provided with two lateral flanges 26, one end of which is provided with a bellows 27. The tangential loading coupling 16 passes through both the lateral flanges 26 and the bellows 27. A flange 28 is provided on the tangential loading coupling 16 that connects to the end face of the bellows 27. The bellows 27 seals and reduces the influence of friction on the accuracy of the test measurement. By connecting the tangential loading coupling 16 through the bellows 27, micron-level displacement loading is achieved. A sample stage 39 is positioned in the middle of the tangential loading coupling 16 within the test vessel 15. A lower sample clamp 23 is mounted on the sample stage 39. The lower sample 25 of the friction pair is fixed to the sample stage 39 via the lower sample clamp 23. The lower sample clamp 23 is precisely adjusted and fixed via a vertical adjusting screw 22, achieving reliable loading and friction pair engagement of the cladding tube sample. The friction pair consists of an upper sample 24 and a lower sample 25 positioned opposite each other; the upper sample 24 is a cylindrical sample, and the lower sample 25 is a plate-shaped sample. The input terminal of the motor 5 is connected to the process monitoring controller 6, which is connected to a display 7 to collect and store test data in real time, preventing data loss and providing human-machine interaction and test process management, simplifying operation. The motor amplitude range is 10–100 μm, and the micro-motion frequency can achieve stable operation at 20 Hz, with a displacement accuracy of 1 μm.

[0037] The normal loading mechanism 9 includes a loading bolt 30, a load sensor 31, a bellows 32, a normal loading coupling 33, and a loading coupling support assembly 34. The specific structure is as follows: one end of the normal loading coupling 33 passes through the test vessel cover 17 and extends into the test vessel 15, and is connected to one end of the vertical upper sample clamp 21. The other end of the upper sample clamp 21 is connected to the upper sample 24 of the friction pair via an upper sample chuck 43. The loading coupling support assembly 34 is installed on the test vessel cover 17, and the other end of the normal loading coupling 33... The load sensor 31 and the loading bolt 30 are connected in sequence. The normal loading shaft 33, the load sensor 31, and the loading bolt 30 are all installed in the loading shaft support assembly 34. The part of the normal loading shaft 33 outside the test vessel 15 is fitted with a bellows 32. The normal loading mechanism 9 applies a load to the load sensor 31 by rotating the loading bolt 30. The applied load range is 10 to 100 N. The normal load is applied through the normal loading shaft 33, through the test vessel cover 17, and through the bellows 32.

[0038] like Figure 2 As shown, the upper and lower sample fixtures for the friction pair include an upper sample fixture 21 and a lower sample fixture 23. One end of the upper sample fixture 21 is fitted with an upper sample 24 via an upper sample chuck 43. The lower sample fixture 23 is provided with a vertical adjustment screw 22, a lower fixture base 41, a lower sample chuck 42, and a wedge block 44. The lower sample 25 is placed on the lower fixture base 41. A wedge block 44 is provided on the top of the lower sample 25. The lower sample chucks 42 are symmetrically arranged on both sides of the wedge block 44. The lower sample chucks 42 are connected to the lower fixture base 41 via the vertical adjustment screw 22. The lower sample chucks 42 and the wedge block 44 are engaged by inclined contact.

[0039] After the upper sample 24 and lower sample 25 of the friction pair are clamped on the sample stage 39 of the tangential loading coupling shaft 16 by the upper sample clamp 21 and the lower sample clamp 23, the loading bolt 30 of the normal loading mechanism 9 provides load to the upper sample 24. The motor 5 is started to drive the tangential loading coupling shaft 16 to reciprocate, which can complete the fretting wear test for the lower sample 25. At the same time, the friction force, contact time, displacement amplitude, etc. of the contact interface are analyzed and measured to study the fretting wear mechanism of the contact interface in real time.

[0040] In practice, first install the upper sample clamp 21 and the lower sample clamp 23, and apply the required normal load to the normal loading coupling 33 using the loading bolt 30. Then, fix the lower sample clamp 23 using the vertical adjusting screw 22. After closing the control valve 4, place the room temperature solid lead-bismuth alloy into the storage vessel 3. Start the heater of the storage vessel 3 and wait for the temperature inside the vessel to reach the set value and stabilize. Connect high-purity argon gas to the storage vessel inlet pipe 40 through the oxygen-controlled mixed gas cylinder 13, close the storage vessel outlet pipe 2, close the test vessel inlet pipe 8, open the test vessel outlet pipe 10, and blow high-purity argon gas into the storage vessel 3 at the controlled rate. The flow rate is 0.1–1 L / min. Liquid lead-bismuth alloy is introduced into the test vessel 15 via the conductive tube 18 using air pressure. After the liquid lead-bismuth alloy in the test vessel 15 completely immerses the upper sample 24 and lower sample 25 of the friction pair, the dissolved oxygen electrode 11 is fully inserted into the liquid lead-bismuth alloy and sealed. The dissolved oxygen value in the liquid lead-bismuth alloy is measured and collected in real time through the oxygen control solenoid valve 12 and the oxygen control system 14. After the test vessel 15 is heated to the target value, the process monitoring controller 6 of the motor 5 is turned on, the test parameters are input, and the displacement monitoring system is used to monitor and record the data. The test continues until the target time. After the test, the experimental data is saved.

[0041] See Figures 1-4 This utility model proposes a method for using a fretting wear test device for a clad tube in an oxygen-controlled liquid lead-bismuth environment. The specific steps are as follows:

[0042] (1) Check the integrity of the fretting wear test assembly, test vessel 15, storage vessel 3, heater, conduction pipe 18, stand 19 and gas control circuit 38, and put the lead-bismuth alloy into the storage vessel 3.

[0043] (2) Use wiping paper to clean the body of storage vessel 3 and the sealing surface of storage vessel lid 1. After cleaning the copper gasket, place it into the sealing groove at the top of the body of storage vessel 3 and place storage vessel lid 1 on the body of storage vessel 3.

[0044] (3) According to the sample requirements, select appropriate upper sample clamp 21 and lower sample clamp 23 and install them in the test vessel 15 at the designated positions of the normal loading coupling 33 and the tangential loading coupling 16. Place two symmetrical lower sample clamps 42 on the lower base 41 of the clamp, and then place the lower sample 25 and the wedge 44 between the lower sample clamps 42. Move the lower sample clamps 42 and the wedge 44 until the surface of the lower sample 25 is horizontal. Then, screw the vertical adjustment screw 22 into the positioning hole from the threaded hole of the lower base 41 of the clamp. The screwing speed should be consistent so that the lower sample 25 is in the center position of the lower base 41 of the clamp and remains horizontal.

[0045] (4) Install the upper sample 24 with the friction pair in the upper sample clamp 21, put the upper sample 24 into the upper sample chuck 43, so that the upper sample 24 is in the center position of the upper sample clamp 21, and move the normal loading shaft 33 and the upper sample clamp 21 by the loading bolt 30, thereby maintaining friction with the lower sample 25 during the test.

[0046] (5) Align the installed fixture lower base 41 with the vertical threaded hole on the sample stage 39, insert the vertical adjustment screw 22 and tighten it to achieve tight fixation between the fixture lower base 41 and the sample stage 39, ensuring that the whole is coaxially fastened. Perform a second tightening to ensure that the lower sample clamp 42 and the upper sample clamp 43 tightly clamp the shell tube, so as to ensure that there is enough friction between the clamp and the shell tube, thereby ensuring that they will not slip relative to each other during the test.

[0047] (6) Use wiping paper to clean the body of the test vessel 15 and the sealing surface of the test vessel lid 17. After cleaning the copper gasket, place it into the sealing groove at the top of the test vessel 15 and place the test vessel lid 17 on the body of the test vessel 15.

[0048] (7) Set the target temperature on the control cabinet. The initial target temperature of the storage vessel 3 and the conductive pipe 18 is 250℃±10℃, and the target temperature of the vessel body of the test vessel 15 is 250℃. Start heating and maintain the target temperature value for 20 to 40 minutes to completely melt the lead-bismuth alloy in the storage vessel.

[0049] (8) Connect high-purity argon gas (volume purity 99.999%) to the gas inlet pipe 40 of the storage vessel, open the valve of the gas inlet pipe 40 of the storage vessel, close the valve of the gas outlet pipe 2 of the storage vessel, close the valve of the gas inlet pipe 8 of the test vessel, open the valve of the gas outlet pipe 10 of the test vessel, and start blowing high-purity argon gas into the storage vessel 3 at a rate of 0.1 to 1 L / min. The liquid lead-bismuth alloy is then introduced into the vessel body of the test vessel 15 through the conductive pipe 18 by the gas pressure.

[0050] (9) After the liquid lead-bismuth alloy in the test vessel 15 has completely immersed the upper sample 24 and lower sample 25 of the friction pair, close the valve of the storage vessel inlet pipe 40 and keep the valve of the storage vessel outlet pipe 2 closed, close the valve of the test vessel outlet pipe 10 and keep the valve of the test vessel inlet pipe 8 closed.

[0051] (10) After preheating the dissolved oxygen electrode 11 at a temperature of 150-200°C for 20-40 minutes, fully insert the dissolved oxygen electrode 11 into the liquid lead-bismuth alloy and seal it; connect the dissolved oxygen electrode 11 to the voltmeter of the oxygen control system 14 to measure and collect the dissolved oxygen value in the liquid lead-bismuth alloy in real time.

[0052] (11) After heating the vessel body of the test vessel 15 to the target value, turn on the process monitoring controller 6 of the motor 5, input the test parameters, and at the same time use the displacement monitoring system to monitor and record the data;

[0053] (12) Input test parameters such as displacement amplitude, loading frequency, and normal force through the process monitoring controller 6 of motor 5, and record data using the acquisition system at the same time.

[0054] (13) Start the test and continue the test until the target cycle. After the fretting wear test is completed, save the experimental data.

[0055] (14) Start cooling down. When the temperature drops to 250℃±10℃, remove the dissolved oxygen electrode 11 and keep the test vessel 15 sealed.

[0056] (15) Connect high-purity argon gas (volume purity 99.999%) to the inlet pipe 8 of the test vessel, open the valve on the outlet pipe 2 of the storage vessel, keep the valve on the inlet pipe 40 of the storage vessel closed, open the valve on the inlet pipe 8 of the test vessel, keep the valve on the outlet pipe 10 of the test vessel closed, and open the valve on the connecting pipe 18; blow high-purity argon gas into the test vessel 15 at a rate of 0.1 to 1 L / min, and use gas pressure to drive the liquid lead-bismuth alloy from the test vessel 15 into the storage vessel 3 through the connecting pipe 18;

[0057] (16) Cool the storage vessel 3, test vessel 15 and the connecting pipe 18 to room temperature, open the test vessel 15, disassemble the sample and store it properly, cover the test vessel lid 17, and the test is over.

[0058] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A fretting wear test device of a cladding tube in a controlled oxygen liquid lead bismuth environment, characterized by, The device's storage vessel and test vessel are fixed on a platform. The test vessel is equipped with a test vessel lid, which has a test vessel outlet pipe and a test vessel inlet pipe connected to a gas control circuit. The storage vessel is equipped with a storage vessel lid, which has a storage vessel outlet pipe and a storage vessel inlet pipe connected to a gas control circuit. The gas control circuit controls the deoxygenation and oxygen content of the liquid lead-bismuth. The bottom of the inner cavities of the storage vessel and the test vessel are connected by a connecting pipe equipped with a control valve to achieve continuous circulation control of the liquid lead-bismuth. The liquid lead-bismuth in the test vessel and the storage vessel are replaced and environmental parameters are adjusted through the test vessel inlet pipe, the storage vessel inlet pipe, the storage vessel outlet pipe, and the test vessel outlet pipe, and the oxygen content is precisely controlled. The test vessel is equipped with a fretting wear test assembly, which includes a tangential loading mechanism and a normal loading mechanism. The tangential loading mechanism and the normal loading mechanism work together to construct the mechanical load environment of the cladding tube during actual service. Heaters are installed on the outer sides of the storage vessel and the test vessel, and the heaters are covered with an insulation layer.

2. The device for testing fretting wear of a cladding tube in a controlled-oxygen liquid lead-bismuth environment according to claim 1, characterized by, The platform is equipped with a lid lifter, which includes a bracket, a lifting component, and an electric push rod. The bracket is set on the platform, and a vertical electric push rod is installed on the bracket. The lower end of the electric push rod is equipped with a lifting component. The lid lifter is connected to the test lid and the storage lid respectively through the lifting component via threads. The lifting and lowering of the electric push rod is controlled by a button switch, which drives the lifting component to pull the test lid and the storage lid, thereby realizing the opening and closing of the test lid and the storage lid.

3. The device for testing fretting wear of a cladding tube in a controlled-oxygen liquid lead-bismuth environment according to claim 1, characterized in that, The gas control loop is connected to the oxygen-controlled mixed gas cylinder via a pipeline, and an oxygen-controlled solenoid valve is installed on the pipeline connecting the oxygen-controlled mixed gas cylinder and the gas control loop. A dissolved oxygen electrode is installed inside the test vessel, and the dissolved oxygen electrode is connected to the oxygen-controlled solenoid valve via a circuit. An oxygen control system is installed on the circuit connecting the dissolved oxygen electrode and the oxygen-controlled solenoid valve. The oxygen-controlled mixed gas cylinder is a cylinder containing a mixture of argon and oxygen, or the oxygen-controlled mixed gas cylinder includes both an argon cylinder and an oxygen cylinder.

4. The device for testing fretting wear of a cladding tube in an oxygen- controlled liquid lead-bismuth environment according to claim 1, characterized in that, The tangential loading mechanism includes a motor, a tangential loading coupling, and a bellows. The specific structure is as follows: one end of the tangential loading coupling passes through the wall of the test vessel and is sealed by the bellows, and is connected to the motor output. Two lateral flanges are provided on the outer wall of the test vessel, with a bellows at one end of each flange. The tangential loading coupling passes through both the lateral flanges and the bellows. A flange connected to the end face of the bellows is provided on the tangential loading coupling. Micrometer-level displacement loading is achieved by connecting the tangential loading coupling through the bellows. A sample stage is set in the middle of the tangential loading coupling inside the test vessel. A lower sample clamp is installed on the sample stage. The lower sample of the friction pair is fixed to the sample stage by the lower sample clamp. The lower sample clamp is adjusted and fixed by a vertical adjusting screw, achieving reliable loading and friction pair engagement of the cladding tube sample.

5. The device for micro-tribological wear test of the cladding tube in the controlled-oxygen liquid lead-bismuth environment according to claim 4, characterized in that, The friction pair is a structure in which the upper and lower specimens are arranged opposite each other. The upper specimen is a cylindrical specimen, and the lower specimen is a plate-shaped specimen. The input end of the motor is connected to the process monitoring controller.

6. The device for micro-tribological wear test of the cladding tube in the controlled-oxygen liquid lead-bismuth environment according to claim 4, characterized in that, The normal loading mechanism includes a loading bolt, a load sensor, a bellows, a normal loading coupling, and a loading coupling support assembly. The specific structure is as follows: One end of the normal loading coupling passes through the test vessel lid and extends into the test vessel, connecting to one end of a vertical upper sample clamp. The other end of the upper sample clamp is connected to the upper sample of the friction pair via an upper sample clamp. A loading coupling support assembly is installed on the test vessel lid. The other end of the normal loading coupling is sequentially connected to the load sensor and the loading bolt. The normal loading coupling, load sensor, and loading bolt are all installed and mounted on the loading coupling support assembly. The portion of the normal loading coupling outside the test vessel is fitted with a bellows. The normal loading mechanism applies a load to the load sensor by rotating the loading bolt, and the normal load is applied through the normal loading coupling passing through the test vessel lid and the bellows.

7. The device for micro-tribological wear test of the cladding tube in the controlled-oxygen liquid lead-bismuth environment according to claim 6, characterized in that, The upper and lower sample fixtures for the friction pair include an upper sample fixture and a lower sample fixture. The upper sample is installed at one end of the upper sample fixture via an upper sample chuck. The lower sample fixture is equipped with a vertical adjustment screw, a lower base of the fixture, a lower sample chuck, and a wedge. The lower sample is placed on the lower base of the fixture. A wedge is placed on the top of the lower sample. Lower sample chucks are symmetrically arranged on both sides of the wedge. The lower sample chucks are connected to the lower base of the fixture via the vertical adjustment screw. The lower sample chucks and the wedges are engaged by inclined contact.

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