A tubular sample dynamic liquid lead-bismuth alloy loop corrosion fatigue test device and a use method thereof

Abstract

The present application relates to the field of fatigue test, in particular to a kind of tubular sample dynamic liquid lead bismuth alloy loop corrosion fatigue test device and use method.Tubular sample is installed between upper and lower base, the lower end of tubular sample is sequentially communicated with the through hole in lower base, liquid lead bismuth alloy inlet pipe, the upper end of tubular sample is sequentially communicated with the through hole in upper base, liquid lead bismuth alloy outlet pipe.Tubular sample outer paste thermocouple real-time monitoring and control liquid lead bismuth temperature, outer surface installation extensometer strain measurement.Liquid lead bismuth is driven by electromagnetic pump through storage tank, enters reaction kettle and is heated and oxygen is controlled, after flow rate is measured by flowmeter, it flows into tubular sample, then backflow to storage tank and forms loop.The outer wall of loop pipeline is equipped with armored electric heating and thermal insulation cotton, to ensure temperature control.The present application realizes the accurate control of high-temperature liquid lead bismuth temperature, dissolved oxygen and flow rate, supports dynamic strain control fatigue test, and evaluates the corrosion fatigue performance of material in flowing high-temperature liquid lead bismuth environment.

Description

Technical Field

[0001] This invention relates to the field of fatigue testing, specifically to a device and method for testing corrosion fatigue of tubular specimens in a dynamic liquid lead-bismuth alloy circuit. The device is used for strain-controlled low-cycle fatigue testing of tubular specimens in a dynamic liquid lead-bismuth alloy circuit to evaluate the corrosion fatigue performance of structural materials under the action of the dynamic liquid lead-bismuth alloy. Background Technology

[0002] Lead-cooled fast reactors (LDFRs) are among the most promising fourth-generation fast reactor types due to their inherent high safety, long lifespan, miniaturization, high power density, and ability to burn nuclear waste. Currently, one of the bottlenecks limiting the development of LFRs is the environmental compatibility of lead-bismuth eutectic and structural materials. Numerous studies have shown that structural materials in high-temperature liquid lead-bismuth alloy environments undergo liquid metal corrosion and embrittlement, significantly reducing their fatigue strength and making them prone to corrosion fatigue cracks. Once these corrosion fatigue cracks penetrate the wall thickness of the service components, causing leakage or instantaneous fracture, the consequences are unimaginable, severely impacting the economics and safety of nuclear power plant operations.

[0003] In actual working conditions, the inside of the lead-cooled fast reactor container is a flowing high-temperature liquid lead-bismuth alloy. However, existing fatigue testing devices for liquid lead-bismuth alloy environments are mainly concentrated in static environments, which cannot meet the testing requirements of the interaction between the dynamic liquid lead-bismuth alloy and mechanical factors under actual working conditions.

[0004] Currently, the patent "A Dynamic Mechanical Property Testing Device for High-Temperature Lead-Bismuth Environment (Publication No. CN 117470693)" achieves dynamic mechanical property testing of high-temperature liquid lead-bismuth in a static reactor by rotating the sample. However, the flow rate generated by rotating the sample is not uniform, and the flow rate on the sample surface is difficult to control precisely during actual operation. Therefore, to address the above problems, this invention develops a fatigue testing device for tubular samples in a dynamic liquid lead-bismuth alloy circuit, used to study the low-cycle fatigue behavior of key equipment structural materials in lead-cooled fast reactors in simulated service environments (flow, high temperature, oxygen control). Summary of the Invention

[0005] The purpose of this invention is to provide a dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device and method for tubular specimens, so as to realize low-cycle fatigue testing of tubular specimens in a fluid dynamic liquid lead-bismuth alloy environment.

[0006] The technical solution of this invention is:

[0007] A dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular samples includes a storage vessel containing liquid lead-bismuth alloy. The storage vessel is connected to the inner cavity of a first reaction vessel via a first circuit pipe. One end of the first circuit pipe is connected to the lower part of the inner cavity of the storage vessel, and the other end passes through the lid of the first reaction vessel and extends to the upper part of the inner cavity of the first reaction vessel. A first liquid lead-bismuth alloy valve and a liquid metal electromagnetic pump are installed on the first circuit pipe. The storage vessel is also connected to a second reaction vessel via a pipe, one end of which passes through the lid of the storage vessel and extends to the upper part of the inner cavity of the storage vessel. The other end of the pipeline passes through the bottom of the second reactor and extends to the lower part of the inner cavity of the second reactor. The bottom of the first reactor is connected to the second loop pipeline through a pipeline equipped with a liquid metal flow meter. The second loop pipeline is connected to the lower end of the tubular sample through-hole through a third liquid lead-bismuth alloy valve and a liquid lead-bismuth alloy inlet pipe on a branch loop. The second loop pipeline is connected to the upper end of the tubular sample through-hole through a fourth liquid lead-bismuth alloy valve and a liquid lead-bismuth alloy outlet pipe on another branch loop. The second loop pipeline is connected to the second reactor through the main loop.

[0008] The aforementioned tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue test device has a storage vessel lid equipped with a storage vessel inlet and a storage vessel outlet. One end of the storage vessel inlet extends to the outside of the storage vessel lid, and the other end passes through the storage vessel lid and extends to the liquid lead-bismuth alloy in the lower part of the storage vessel's inner cavity. One end of the storage vessel outlet extends to the outside of the storage vessel lid, and the other end passes through the storage vessel lid and extends to the upper part of the liquid lead-bismuth alloy in the storage vessel's inner cavity.

[0009] The aforementioned tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device has an oxygen-controlled mixed gas inlet, an oxygen-controlled mixed gas outlet, and a dissolved oxygen electrode on the lid of the first reaction vessel. Specifically: one end of the oxygen-controlled mixed gas inlet extends to the outside of the first reaction vessel, and this end is connected to an oxygen-controlled mixed gas cylinder via a pipeline and an oxygen-controlled solenoid valve on the pipeline; the other end of the oxygen-controlled mixed gas inlet extends through a channel on the first reaction vessel to the lower part of the inner cavity of the first reaction vessel. One end of the oxygen-controlled mixed gas outlet extends to the outside of the first reaction vessel, and the other end extends through a channel on the first reaction vessel to the upper part of the inner cavity of the first reaction vessel. The upper end of the dissolved oxygen electrode extends above the lid of the first reaction vessel, and the lower end extends to the middle of the inner cavity of the first reaction vessel. The oxygen control system controller is connected to the oxygen-controlled solenoid valve and the dissolved oxygen electrode via wiring.

[0010] The aforementioned tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device has a second reaction vessel with a second reaction vessel outlet. One end of the second reaction vessel outlet extends to the outside of the second reaction vessel lid, and the other end passes through the second reaction vessel lid and extends to the upper part of the inner cavity of the second reaction vessel. One end of the main circuit of the second circuit pipeline passes through the second reaction vessel lid and extends to the upper part of the inner cavity of the second reaction vessel, and the other end of the main circuit of the second circuit pipeline is connected to a liquid metal flow meter through a pipeline.

[0011] The aforementioned dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens comprises a second circuit pipeline consisting of a main circuit and two branch circuits. The main circuit is vertically connected to the two branch circuits. A second liquid lead-bismuth alloy valve is installed on the main circuit, and a third and a fourth liquid lead-bismuth alloy valve are respectively installed on the two branch circuits. One end of the liquid lead-bismuth alloy inlet pipe is connected to the lower end of the through hole of the tubular specimen, and the other end of the liquid lead-bismuth alloy inlet pipe is connected to one branch circuit through a first sealing joint. One end of the liquid lead-bismuth alloy outlet pipe is connected to the upper end of the through hole of the tubular specimen, and the other end of the liquid lead-bismuth alloy outlet pipe is connected to another branch circuit through a second sealing joint.

[0012] The aforementioned dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens has a gauge length section whose external shape and dimensions are designed based on standard rod-shaped fatigue specimens. The interior of the tubular specimen is a through hole, and the wall thickness of the gauge length section is 2~5mm. Steps with clamping functions are provided at both ends of the tubular specimen. The through hole is a cylindrical hole in the middle and a conical hole and a threaded hole formed by V-shaped sealing surfaces arranged symmetrically at both ends of the cylindrical hole. The cylindrical hole in the middle is connected to the threaded hole on the outside through the V-shaped sealing surface.

[0013] The aforementioned dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens has two ends of the tubular specimen sealed and connected to sealing plugs via matching clamping bolts. The sealing plugs are two symmetrically positioned at the top and bottom of the tubular specimen, each with a cylindrical portion and a cylindrical step at its head. The outer end face of the cylindrical step at one end of each sealing plug corresponds to the V-shaped sealing surface of the through-hole inside the tubular specimen and is matched with the V-shaped sealing surface via a chamfer. The clamping bolt is a stepped cylindrical structure with an external thread on its smaller diameter portion. This smaller diameter portion of the clamping bolt corresponds to and matches the threaded hole of the through-hole inside the tubular specimen. The clamping bolt has a through-hole in its center, allowing it to fit over the cylindrical portion of the sealing plug. The smaller diameter end of the clamping bolt corresponds to and is in close contact with the inner end face of the cylindrical step of the sealing plug. After the sealing plug and clamping bolt are matched, the clamping bolt is connected to the threaded hole of the tubular specimen via its external thread.

[0014] The aforementioned tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device has a sealing plug with an internal through hole. The other end of the lower sealing plug is connected to one end of the liquid lead-bismuth alloy inlet pipe through the lower through hole in the lower base via a threaded seal. The other end of the upper sealing plug is connected to one end of the liquid lead-bismuth alloy outlet pipe through the upper through hole in the upper base via a threaded seal, thereby achieving connection with the second circuit pipeline of the dynamic liquid lead-bismuth alloy. The liquid lead-bismuth alloy inlet pipe and the liquid lead-bismuth alloy outlet pipe are wrapped with armored electric heat tracing and insulation cotton.

[0015] The aforementioned dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens has thermocouples attached to the outer surface of the gauge length section of the tubular specimen to monitor / control the temperature of the liquid lead-bismuth alloy flowing through the tubular specimen in real time. The tubular specimen is mounted on the fatigue fixture of the fatigue testing machine via an upper base and a lower base. After the tubular specimen is mounted on the fatigue testing machine, a strain extensometer is installed on the outer surface of the gauge length section of the tubular specimen. The strain extensometer is connected to the fatigue testing machine to monitor / control the strain of the gauge length section of the tubular specimen in real time during the fatigue test.

[0016] The fitted sealing plug and clamping bolt are installed into the threaded hole of the tubular specimen. By tightening the clamping bolt, the sealing plug is vertically compressed, causing the head of the sealing plug to contact the V-shaped sealing surface of the tubular specimen to form a hard seal. After tightening, a sealing effect is achieved. After the seal is installed, it can achieve a flow rate of 0~4m / s, a temperature of 300~550℃, and an oxygen concentration of saturated oxygen ~10. - 8 wt.% Controllable corrosion fatigue test of liquid lead-bismuth alloy.

[0017] The method of using the aforementioned tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device includes the following steps:

[0018] (1) The clamping bolt is fitted onto the sealing plug. The clamping bolt and sealing plug are installed in the threaded holes at both ends of the tubular specimen. The clamping bolt is tightened so that the heads of the upper and lower sealing plugs form a hard seal with the V-shaped sealing surface of the tubular specimen. At the same time, the fatigue fixture of the fatigue testing machine is used to clamp the tubular specimen through the upper and lower bases.

[0019] (2) The liquid lead-bismuth alloy inlet pipe is connected to the first sealing joint of the second circuit pipe by a thread, and the liquid lead-bismuth alloy outlet pipe is connected to the second sealing joint of the second circuit pipe by a thread, thereby realizing the connection with the dynamic liquid lead-bismuth alloy circuit.

[0020] (3) The liquid lead-bismuth alloy inlet pipe and liquid lead-bismuth alloy outlet pipe are wrapped with armored electric heat tracing and heat insulation cotton, and heated by power supply; thermocouples are pasted on the surface of the tubular sample, and extensometers are clamped on the tubular sample;

[0021] (4) The first loop pipeline is wrapped with armored electric heat tracing and insulation cotton, and the power supply and temperature control are set to 400°C. The control cabinet supplies power and controls the temperature of the storage vessel, the first reaction vessel and the second reaction vessel through the line. The liquid lead-bismuth alloy is placed in the storage vessel and heated and the temperature is controlled as the storage vessel melts. The liquid metal electromagnetic pump is powered and a voltage of 150V±30V is applied to make the liquid metal electromagnetic pump run idle and heat the internal pipeline of the liquid metal electromagnetic pump to 400°C.

[0022] (5) When the temperature of the storage vessel, the loop pipeline, the internal pipeline of the liquid metal electromagnetic pump, the first reaction vessel and the second reaction vessel is >350℃, open the first liquid lead-bismuth alloy valve, close the other liquid lead-bismuth alloy valves, and pass high-purity argon gas through the gas inlet of the storage vessel so that the liquid lead-bismuth alloy in the storage vessel flows into the liquid metal electromagnetic pump along the pipeline, thereby meeting the start-up requirements of the liquid metal electromagnetic pump.

[0023] (6) Close the inlet of the storage vessel, open the outlet of the storage vessel, depressurize the storage vessel, then close the outlet of the storage vessel, open the first liquid lead-bismuth alloy valve, set the voltage of the liquid metal electromagnetic pump control cabinet to 250V, the liquid lead-bismuth alloy in the pipe begins to flow, the liquid metal flow meter displays the real-time flow rate, and a dynamic liquid lead-bismuth alloy circuit is formed.

[0024] (7) Open the oxygen control system controller to control the air intake of the oxygen control solenoid valve to achieve oxygen control of the liquid lead-bismuth alloy in the inner cavity of the first reactor;

[0025] (8) Open the two liquid lead-bismuth alloy valves on the branch circuit leading to the fatigue testing machine, close the first liquid lead-bismuth alloy valve, and the liquid lead-bismuth alloy flows through the tubular specimen, enabling fatigue testing of the tubular specimen in a dynamic liquid lead-bismuth alloy environment.

[0026] (9) After the fatigue test, turn off the power supply of the liquid metal electromagnetic pump, introduce high-purity argon into the oxygen-controlled mixture inlet, and put the liquid lead-bismuth alloy in the first reaction vessel, the tubular sample, and the second loop pipeline into the second reaction vessel. Then, blow it back into the storage vessel through the pipeline connecting the second reaction vessel and the storage vessel to realize the recovery of liquid lead-bismuth alloy and disassemble the fatigue sample under normal temperature air conditions.

[0027] The design concept of this invention is:

[0028] In this invention, a tubular sample is installed between upper and lower bases. The lower end of the tubular sample is sequentially connected to an internal through-hole in the lower base and an inlet pipe for liquid lead-bismuth alloy, while the upper end is sequentially connected to an internal through-hole in the upper base and an outlet pipe for liquid lead-bismuth alloy. A thermocouple is attached to the outside of the tubular sample to monitor and control the temperature of the liquid lead-bismuth in real time, and an extensometer is installed on the outer surface to measure strain. The liquid lead-bismuth is driven by an electromagnetic pump through a storage vessel, enters a reaction vessel for heating and oxygen control, flows into the tubular sample after its flow rate is measured by a flow meter, and then flows back to the storage vessel to form a loop. The outer wall of the loop pipe is equipped with armored electric heating and insulation cotton to ensure temperature control. This invention achieves precise control of the temperature, dissolved oxygen, and flow rate of high-temperature liquid lead-bismuth, supports dynamic strain-controlled fatigue testing, and evaluates the corrosion fatigue performance of materials in a flowing high-temperature liquid lead-bismuth environment.

[0029] The advantages and beneficial effects of this invention are:

[0030] 1. This invention provides a dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device and its usage method for tubular specimens. The dynamic liquid lead-bismuth alloy circuit is reasonably designed and cleverly combined with a low-cycle fatigue testing device to realize the low-cycle fatigue test of tubular specimens under dynamic (0~4m / s) liquid lead-bismuth alloy circuit.

[0031] 2. The device of the present invention connects the dynamic liquid lead-bismuth alloy circuit and the tubular fatigue sample through a conductive tube. After the test is completed, the liquid lead-bismuth alloy in the tubular sample can be transferred back to the storage vessel by pressing in argon gas. This makes it convenient to load and unload the fatigue sample in room temperature air. The operation is simple and convenient and does not involve contact with lead-bismuth alloy vapor. Attached Figure Description

[0032] Figure 1 This is a structural diagram of the low-cycle fatigue experimental setup and the dynamic liquid lead-bismuth alloy circuit.

[0033] Figure 2 This is a schematic diagram of the installation of tubular specimens in a fatigue testing machine.

[0034] Figure 3 This is a schematic diagram of a tubular sample.

[0035] Figure 4 This is a schematic diagram of the installation at the upper end of the tubular sample.

[0036] In the diagram: 1. Storage vessel; 2. First liquid lead-bismuth alloy valve; 3. Liquid metal electromagnetic pump; 4. First reaction vessel; 5. Liquid metal flow meter; 6. Fatigue testing machine; 7. Second reaction vessel; 8. Storage vessel outlet; 9. Storage vessel inlet; 10. Liquid lead-bismuth alloy; 11. Oxygen-controlled mixed gas inlet; 12. Oxygen-controlled mixed gas outlet; 13. Dissolved oxygen electrode; 14. Oxygen-controlled solenoid valve; 15. Oxygen-controlled mixed gas cylinder; 16. Oxygen control system controller; 17. First sealing joint; 18. Tubular sample; 19. First loop pipeline; 20. Second reaction vessel outlet; 21. Main loop; 22. Second liquid lead-bismuth alloy valve; 23. Third liquid lead-bismuth alloy valve; 24. Branch loop; 25. Fourth liquid lead-bismuth alloy valve; 26. Second sealing joint; 27. Liquid lead-bismuth alloy inlet pipe; 28. Liquid lead-bismuth alloy outlet pipe; 29. ​​Upper base; 30. Lower base; 31. Threaded hole; 32. Thermocouple; 33. V-shaped sealing surface; 34 Strain extensometer; 35 Fatigue test shaft; 36 Step; 37 Clamping bolt; 38 Sealing plug; 39 Secondary circuit pipe; 40 Upper through hole; 41 Lower through hole. Detailed Implementation

[0037] like Figures 1-2 As shown, this invention provides a dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens, mainly comprising: a storage vessel 1, a first liquid lead-bismuth alloy valve 2, a liquid metal electromagnetic pump 3, a first reaction vessel 4, a liquid metal flow meter 5, a fatigue testing machine 6, a second reaction vessel 7, a storage vessel outlet 8, a storage vessel inlet 9, liquid lead-bismuth alloy 10, an oxygen-controlled mixed gas inlet 11, an oxygen-controlled mixed gas outlet 12, a dissolved oxygen electrode 13, an oxygen-controlled solenoid valve 14, an oxygen-controlled mixed gas cylinder 15, an oxygen-controlled system controller 16, a first sealing joint 17, a tubular specimen 18, a first circuit pipeline 19, a second reaction vessel outlet 20, a main circuit 21, a second liquid lead-bismuth alloy valve 22, a third liquid lead-bismuth alloy valve 23, a branch circuit 24, a fourth liquid lead-bismuth alloy valve 25, and a second sealing joint 26. The specific structure is as follows: 27. Liquid lead-bismuth alloy inlet pipe; 28. Liquid lead-bismuth alloy outlet pipe; 29. ​​Upper base; 30. Lower base; 31. Threaded hole; 32. Thermocouple; 33. V-shaped sealing surface; 34. Strain extensometer; 35. Fatigue test shaft; 36. Step; 37. Clamping bolt; 38. Sealing plug; 39. Secondary circuit pipe.

[0038] The storage vessel 1 contains liquid lead-bismuth alloy 10. The storage vessel 1 is connected to the inner cavity of the first reaction vessel 4 via a first loop pipe 19. One end of the first loop pipe 19 is connected to the lower part of the inner cavity of the storage vessel 1, and the other end passes through the lid of the first reaction vessel 4 and extends to the upper part of the inner cavity of the first reaction vessel 4. The first loop pipe 19 is equipped with a first liquid lead-bismuth alloy valve 2 and a liquid metal electromagnetic pump 3. The storage vessel 1 is also connected to the second reaction vessel 7 via a pipeline. One end of the pipeline passes through the lid of the storage vessel 1 and extends to the upper part of the inner cavity of the storage vessel 1, and the other end passes through the bottom of the second reaction vessel 7 and extends to the lower part of the inner cavity of the second reaction vessel 7. The bottom of the first reactor 4 is connected to the second loop pipe 39 via a pipeline. The pipeline is equipped with a liquid metal flow meter 5. The second loop pipe 39 is connected to the lower end of the through hole of the tubular sample 18 via a third liquid lead-bismuth alloy valve 23 and a liquid lead-bismuth alloy inlet pipe 27 on a branch loop 24. The second loop pipe 39 is connected to the upper end of the through hole of the tubular sample 18 via a fourth liquid lead-bismuth alloy valve 25 and a liquid lead-bismuth alloy outlet pipe 28 on another branch loop. The second loop pipe 39 is connected to the second reactor 7 via the main loop 21.

[0039] The storage vessel 1 has an air inlet 9 and an air outlet 8 on its lid. One end of the air inlet 9 extends to the outside of the lid of the storage vessel 1, and the other end of the air inlet 9 passes through the lid of the storage vessel 1 and extends to the liquid lead-bismuth alloy 10 in the lower part of the inner cavity of the storage vessel 1. One end of the air outlet 8 extends to the outside of the lid of the storage vessel 1, and the other end of the air outlet 8 passes through the lid of the storage vessel 1 and extends to the upper part of the liquid lead-bismuth alloy 10 in the inner cavity of the storage vessel 1.

[0040] The lid of the first reactor 4 is equipped with an oxygen-controlled mixed gas inlet 11, an oxygen-controlled mixed gas outlet 12, and a dissolved oxygen electrode 13. One end of the oxygen-controlled mixed gas inlet 11 extends to the outside of the first reactor 4, and is connected to an oxygen-controlled mixed gas cylinder 15 via a pipeline and an oxygen-controlled solenoid valve 14 on the pipeline. The other end of the oxygen-controlled mixed gas inlet 11 extends through a channel on the first reactor 4 to the lower part of the inner cavity of the first reactor 4. One end of the oxygen-controlled mixed gas outlet 12 extends to the outside of the first reactor 4, and the other end extends through a channel on the first reactor 4 to the upper part of the inner cavity of the first reactor 4. The upper end of the dissolved oxygen electrode 13 extends above the lid of the first reactor 4, and the lower end of the dissolved oxygen electrode 13 extends to the middle of the inner cavity of the first reactor 4. The oxygen control system controller 16 is connected to the oxygen control solenoid valve 14 and the dissolved oxygen electrode 13 via wiring. The oxygen control system controller 16 controls the air intake of the oxygen control solenoid valve 14 to achieve oxygen control of the liquid lead-bismuth alloy in the inner cavity of the first reaction vessel 4.

[0041] The second reactor 7 is provided with a second reactor outlet 20. One end of the second reactor outlet 20 extends to the outside of the reactor lid of the second reactor 7, and the other end of the second reactor outlet 20 passes through the reactor lid of the second reactor 7 and extends to the upper part of the inner cavity of the second reactor 7. One end of the main circuit 21 of the second circuit pipe 39 passes through the reactor lid of the second reactor 7 and extends to the upper part of the inner cavity of the second reactor 7. The other end of the main circuit 21 of the second circuit pipe 39 is connected to the liquid metal flow meter 5 through a pipeline.

[0042] The second loop pipe 39 is a combination of the main loop 21 and two branch loops 24. The main loop 21 is perpendicularly connected to the two branch loops 24. The main loop 21 is equipped with a second liquid lead-bismuth alloy valve 22, and the two branch loops 24 are equipped with a third liquid lead-bismuth alloy valve 23 and a fourth liquid lead-bismuth alloy valve 25, respectively. One end of the liquid lead-bismuth alloy inlet pipe 27 is connected to the lower end of the through hole of the tubular sample 18, and the other end of the liquid lead-bismuth alloy inlet pipe 27 is connected to one branch loop 24 through the first sealing joint 17. One end of the liquid lead-bismuth alloy outlet pipe 28 is connected to the upper end of the through hole of the tubular sample 18, and the other end of the liquid lead-bismuth alloy outlet pipe 28 is connected to another branch loop 24 through the second sealing joint 29.

[0043] like Figure 3 As shown, the external shape and dimensions of the gauge length section of the tubular specimen 18 are designed based on the standard rod-shaped fatigue specimen. The interior of the tubular specimen 18 is a through hole, and the wall thickness of the gauge length section is 2~5 mm. Steps 36 with clamping function are provided at both ends of the tubular specimen 18 to facilitate loading and unloading. The through hole is a cylindrical hole in the middle and a conical hole and a threaded hole 31 formed by V-shaped sealing surfaces 33 arranged symmetrically at both ends of the cylindrical hole. The cylindrical hole in the middle of the through hole is connected to the threaded hole 31 on the outer side through the V-shaped sealing surface 33.

[0044] like Figure 1 , Figure 4As shown, the upper and lower ends of the tubular specimen 18 are installed in the same way. The two ends of the tubular specimen 18 are respectively sealed to the sealing plugs 38 by matching clamping bolts 37. The sealing plugs 38 are two symmetrically arranged at the upper and lower ends of the tubular specimen 18. The sealing plugs 38 have a cylindrical part and a cylindrical step at the head. The outer end face of the cylindrical step at one end of each sealing plug 38 corresponds to the V-shaped sealing surface 33 of the internal through hole of the tubular specimen 18, and matches the V-shaped sealing surface 33 by a chamfer. The clamping bolt 38 is a stepped cylindrical structure with external threads on its smaller diameter portion. The smaller diameter portion of the clamping bolt 37 corresponds to and matches the threaded hole 31 of the through hole inside the tubular sample 18. The clamping bolt 37 has a through hole in the center, so that the clamping bolt 37 fits onto the cylindrical portion of the sealing plug 38. The smaller diameter end of the clamping bolt 37 corresponds to and is in close contact with the inner end face of the cylindrical step of the sealing plug 38. After the sealing plug 38 and the clamping bolt 37 are matched, the clamping bolt 37 is connected to the threaded hole 31 of the tubular sample 18 through the external threads.

[0045] The sealing plug 38 has an internal through-hole. The other end of the lower sealing plug is connected to one end of the liquid lead-bismuth alloy inlet pipe 27 via a threaded seal through the lower through-hole 41 in the lower base 30. The other end of the upper sealing plug is connected to one end of the liquid lead-bismuth alloy outlet pipe 28 via a threaded seal through the upper through-hole 40 in the upper base 29, thus connecting to the second loop pipe 39 of the dynamic liquid lead-bismuth alloy. The liquid lead-bismuth alloy inlet pipe 27 and liquid lead-bismuth alloy outlet pipe 28 are wrapped with armored electric heat tracing and insulation cotton, and heated by electricity. A thermocouple 32 is attached to the outer surface of the gauge section of the tubular sample 18 to monitor / control the temperature of the liquid lead-bismuth alloy flowing through the tubular sample 18 in real time. The tubular specimen 18 is mounted on the fatigue test shaft 35 of the fatigue testing machine 6 via the upper base 29 and the lower base 30. After the tubular specimen 18 is mounted on the fatigue testing machine 6, a strain extensometer 34 is installed on the outer surface of the gauge length section of the tubular specimen 18. The strain extensometer 34 is connected to the fatigue testing machine 6 to monitor / control the strain of the gauge length section of the tubular specimen 18 in real time during the fatigue test.

[0046] The fitted sealing plug 38 and clamping bolt 37 are installed in the threaded hole 31 of the tubular sample 18. By tightening the clamping bolt 37, the sealing plug 38 is vertically compressed, causing the head of the sealing plug 38 to make line contact with the V-shaped sealing surface 33 of the tubular sample 18 to form a hard seal. After tightening, a sealing effect is achieved. After the seal is installed, it can achieve flow rate (0~4m / s), temperature (300~550℃), and oxygen concentration (saturated oxygen~10). -8 Controllable corrosion fatigue test of liquid lead-bismuth alloy (wt.%).

[0047] The overall preheating and insulation method for the dynamic liquid lead-bismuth alloy circuit is as follows: The first circuit pipe 19 is wrapped with armored electric heat tracing and insulation cotton, and the power supply and temperature control are set to 400℃; the control cabinet supplies power and controls the temperature of the storage vessel 1, the first reaction vessel 4, and the second reaction vessel 7 through circuits. The liquid lead-bismuth alloy 10 is placed in the storage vessel 1, where it is heated and melted and the temperature is controlled. The liquid metal electromagnetic pump 3 is powered by applying a 150V voltage, causing the liquid metal electromagnetic pump 3 to run idle, and the internal pipes of the liquid metal electromagnetic pump 3 are heated to 400℃.

[0048] When the temperature of storage vessel 1, first loop pipeline 19, internal pipeline of liquid metal electromagnetic pump 3, first reaction vessel 4 and second reaction vessel 7 is >350℃, open the first liquid lead-bismuth alloy valve 2, close other liquid lead-bismuth alloy valves, and pass high-purity argon gas (volume purity 99.999%) through the storage vessel inlet 9, so that the liquid lead-bismuth alloy 10 in storage vessel 1 can flow into liquid metal electromagnetic pump 3 along the pipeline, meeting the start-up requirements of liquid metal electromagnetic pump 3; close the storage vessel inlet 9, open the storage vessel outlet 8, depressurize storage vessel 1, then close the storage vessel outlet 8, open the second liquid lead-bismuth alloy valve 22 on the second loop pipeline 39, set the voltage of liquid metal electromagnetic pump 3 to 250V, the liquid lead-bismuth alloy 10 in the pipe begins to flow, and the liquid metal flow meter 5 displays the real-time flow rate, forming a dynamic liquid lead-bismuth alloy loop.

[0049] The upper end of the dissolved oxygen electrode 13 extends above the lid of the first reactor 4, and the lower end extends to the middle of the inner cavity of the first reactor 4. One end of the oxygen-controlled gas inlet 11 extends to the outside of the first reactor 4, and the other end extends through a channel on the first reactor 4 to the lower part of the inner cavity of the first reactor 4; one end of the oxygen-controlled gas outlet 12 extends to the outside of the first reactor 4, and the other end extends through a channel on the first reactor 4 to the upper part of the inner cavity of the first reactor 4. The oxygen control system controller 16 controls the intake volume of the oxygen control solenoid valve 14 to achieve oxygen control of the liquid lead-bismuth alloy in the inner cavity of the first reactor 4.

[0050] Open the two liquid lead-bismuth alloy valves (third liquid lead-bismuth alloy valve 23 and fourth liquid lead-bismuth alloy valve 25) on the branch circuit 24 leading to the fatigue testing machine 6, and close the second liquid lead-bismuth alloy valve 22. The liquid lead-bismuth alloy flows through the tubular sample 18, enabling fatigue testing of the tubular sample 18 in a dynamic liquid lead-bismuth alloy environment. After the fatigue test, turn off the power to the liquid metal electromagnetic pump 3, and introduce high-purity argon gas (volume purity 99.999%) into the oxygen-controlled mixed gas inlet 11. The liquid lead-bismuth alloy in the first reaction vessel 4, the tubular sample 18, and the second circuit pipe 39 enters the second reaction vessel 7, and is then blown back to the storage vessel 1 through the pipe connecting the second reaction vessel 7 and the storage vessel 1, realizing the recovery of liquid lead-bismuth alloy and facilitating the disassembly of fatigue samples under normal temperature air conditions.

[0051] The fatigue fixture of the fatigue testing machine 6 is a U-shaped structure (actuator on top, bottom is steel plate). The fatigue testing machine 6 has load control, displacement control and strain control modes, and can realize functions such as triangular wave, sine wave, trapezoidal wave and combined waveform. Example

[0052] like Figures 1-2 As shown, the installation steps and usage method of the tubular sample dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device of the present invention are as follows:

[0053] (1) The clamping bolt 37 is fitted onto the sealing plug 38. The clamping bolt 37 and the sealing plug 38 are installed in the threaded holes 31 at both ends of the tubular specimen 18. The clamping bolt 37 is tightened so that the heads of the upper and lower sealing plugs 38 form a hard seal with the V-shaped sealing surface 33 of the tubular specimen 18. At the same time, the tubular specimen 18 is clamped by the fatigue testing machine through the upper base 29 and the lower base 30.

[0054] (2) The liquid lead-bismuth alloy inlet pipe 27 is connected to the first sealing joint 17 of the second circuit pipe 39 by a thread, and the liquid lead-bismuth alloy outlet pipe 28 is connected to the second sealing joint 26 of the second circuit pipe 39 by a thread, thereby realizing the connection with the dynamic liquid lead-bismuth alloy circuit.

[0055] (3) The liquid lead-bismuth alloy inlet pipe 27 and liquid lead-bismuth alloy outlet pipe 28 are wrapped with armored electric heat tracing and heat insulation cotton, and heated by electricity. Thermocouple 32 is pasted on the surface of tubular sample 18, and extensometer 28 is clamped on tubular sample 18.

[0056] (4) The first loop pipe 19 is wrapped with armored electric heat tracing and insulation cotton, and the power supply and temperature control are set to 400℃. The control cabinet supplies power and controls the temperature of the storage vessel 1, the first reaction vessel 4 and the second reaction vessel 7 through the circuit. The liquid lead-bismuth alloy 10 is placed in the storage vessel 1 and is heated and the temperature is controlled as the storage vessel 1 melts. The liquid metal electromagnetic pump 3 is powered by applying a voltage of 150V to make the liquid metal electromagnetic pump 3 run idle and heat the internal pipe of the liquid metal electromagnetic pump 3 to 400℃.

[0057] (5) When the temperature of the storage vessel 1, the first loop pipeline 19, the internal pipeline of the liquid metal electromagnetic pump 3, the first reaction vessel 4 and the second reaction vessel 7 is >350℃, open the first liquid lead-bismuth alloy valve 2 and the second liquid lead-bismuth alloy valve 22, close the other liquid lead-bismuth alloy valves, and pass high-purity argon gas (volume purity 99.999%) through the gas inlet 9 of the storage vessel, the liquid lead-bismuth alloy in the storage vessel 1 can flow into the liquid metal electromagnetic pump 3 along the pipeline, thus meeting the start-up requirements of the liquid metal electromagnetic pump 3.

[0058] (6) Close the air inlet 9 of the storage vessel, open the air outlet 8 of the storage vessel, depressurize the storage vessel 1, then close the air outlet 8 of the storage vessel, open the first liquid lead-bismuth alloy valve 2, set the voltage of the liquid metal electromagnetic pump 3 control cabinet to 250V, the liquid lead-bismuth alloy in the pipe begins to flow, the liquid metal flow meter 5 displays the real-time flow rate, and a dynamic liquid lead-bismuth alloy circuit is formed.

[0059] (7) Open the oxygen control system controller 16 to control the air intake of the oxygen control solenoid valve 14, so as to realize the oxygen control of the liquid lead-bismuth alloy in the inner cavity of the first reactor 4.

[0060] (8) Open the two liquid lead-bismuth alloy valves on the branch circuit 24 leading to the fatigue testing machine 6, close the second liquid lead-bismuth alloy valve 22, and the liquid lead-bismuth alloy flows through the tubular specimen 18, enabling the tubular specimen 18 to undergo fatigue testing in a dynamic liquid lead-bismuth alloy environment.

[0061] (9) After the fatigue test, turn off the power of the liquid metal electromagnetic pump 3 and introduce high-purity argon gas (volume purity 99.999%) into the oxygen-controlled gas inlet 11. The liquid lead-bismuth alloy in the first reaction vessel 4, the tubular sample 18, and the second loop pipeline 39 is introduced into the second reaction vessel 7 and then blown back to the storage vessel 1 through the pipeline connected to the storage vessel 1 of the second reaction vessel 7, so as to realize the recovery of liquid lead-bismuth alloy and facilitate the disassembly of fatigue samples under normal temperature air conditions.

[0062] The results show that the present invention can precisely control the temperature, dissolved oxygen and flow rate parameters of high-temperature liquid lead-bismuth alloy, realize the environmental strain controlled fatigue test of tubular specimens in high-temperature liquid lead-bismuth alloy, and evaluate the corrosion fatigue performance of structural materials under the action of fluid high-temperature liquid lead-bismuth alloy.

Claims

1. A dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens, characterized in that, The storage vessel contains liquid lead-bismuth alloy. The storage vessel is connected to the inner cavity of a first reaction vessel via a first loop pipe. One end of the first loop pipe is connected to the lower part of the inner cavity of the storage vessel, and the other end passes through the lid of the first reaction vessel and extends to the upper part of the inner cavity. The first loop pipe is equipped with a first liquid lead-bismuth alloy valve and a liquid metal electromagnetic pump. The storage vessel is also connected to a second reaction vessel via a pipeline. One end of the pipeline passes through the lid of the storage vessel and extends to the upper part of the inner cavity, and the other end passes through the second reaction vessel. The bottom of the first reactor extends into the lower part of the inner cavity of the second reactor; the bottom of the first reactor is connected to the second loop pipeline through a pipeline, which is equipped with a liquid metal flow meter; the second loop pipeline is connected to the lower end of the tubular sample through-hole through a third liquid lead-bismuth alloy valve and a liquid lead-bismuth alloy inlet pipe on a branch loop; the second loop pipeline is connected to the upper end of the tubular sample through-hole through a fourth liquid lead-bismuth alloy valve and a liquid lead-bismuth alloy outlet pipe on another branch loop; the second loop pipeline is connected to the second reactor through the main loop. The storage vessel has an air inlet and an air outlet on its lid. One end of the air inlet extends to the outside of the lid, and the other end passes through the lid and extends to the liquid lead-bismuth alloy in the lower part of the vessel's internal cavity. One end of the air outlet extends to the outside of the lid, and the other end passes through the lid and extends to the upper part of the liquid lead-bismuth alloy in the vessel's internal cavity. The first reactor lid is equipped with an oxygen-controlled mixed gas inlet, an oxygen-controlled mixed gas outlet, and a dissolved oxygen electrode. One end of the oxygen-controlled mixed gas inlet extends to the outside of the first reactor and is connected to an oxygen-controlled mixed gas cylinder via a pipeline and an oxygen-controlled solenoid valve on the pipeline. The other end of the oxygen-controlled mixed gas inlet extends through a channel on the first reactor to the lower part of the reactor's inner cavity. One end of the oxygen-controlled mixed gas outlet extends to the outside of the first reactor and the other end extends through a channel on the first reactor to the upper part of the reactor's inner cavity. The upper end of the dissolved oxygen electrode extends above the reactor lid, and the lower end extends to the middle of the reactor's inner cavity. The oxygen control system controller is connected to the oxygen-controlled solenoid valve and the dissolved oxygen electrode via wiring. The second reactor is provided with a second reactor outlet. One end of the second reactor outlet extends to the outside of the reactor lid, and the other end of the second reactor outlet passes through the reactor lid and extends to the upper part of the reactor body cavity. One end of the main circuit of the second circuit pipe passes through the reactor lid and extends to the upper part of the reactor body cavity, and the other end of the main circuit of the second circuit pipe is connected to the liquid metal flow meter through a pipeline.

2. The tubular specimen dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device according to claim 1, characterized in that, The second loop is a combination of a main loop and two branch loops. The main loop is perpendicularly connected to the two branch loops. The main loop is equipped with a second liquid lead-bismuth alloy valve, and the two branch loops are equipped with a third liquid lead-bismuth alloy valve and a fourth liquid lead-bismuth alloy valve, respectively. One end of the liquid lead-bismuth alloy inlet pipe is connected to the lower end of the through hole of the tubular sample, and the other end of the liquid lead-bismuth alloy inlet pipe is connected to one branch loop through a first sealing joint. One end of the liquid lead-bismuth alloy outlet pipe is connected to the upper end of the through hole of the tubular sample, and the other end of the liquid lead-bismuth alloy outlet pipe is connected to another branch loop through a second sealing joint.

3. The dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens according to claim 1, characterized in that, The external shape and dimensions of the gauge length section of the tubular specimen are designed based on the standard rod-shaped fatigue specimen. The interior of the tubular specimen is a through hole, and the wall thickness of the gauge length section is 2~5 mm. Steps with clamping function are provided at both ends of the tubular specimen. The through hole is a cylindrical hole in the middle and a conical hole and a threaded hole formed by V-shaped sealing surfaces arranged symmetrically at both ends of the cylindrical hole. The cylindrical hole in the middle of the through hole is connected to the threaded hole on the outside through the V-shaped sealing surface.

4. The dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens according to claim 3, characterized in that, Both ends of the tubular specimen are sealed to sealing plugs via matching clamping bolts. Two sealing plugs are symmetrically positioned at the top and bottom of the tubular specimen. Each sealing plug has a cylindrical portion and a cylindrical step at its head. The outer end face of the cylindrical step at one end of each sealing plug corresponds to the V-shaped sealing surface of the through-hole inside the tubular specimen and is matched with the V-shaped sealing surface via a chamfer. The clamping bolt is a stepped cylindrical structure with external threads on its smaller diameter portion. The smaller diameter portion of the clamping bolt corresponds to and matches the threaded hole of the through-hole inside the tubular specimen. The clamping bolt has a through-hole in its center, allowing it to fit over the cylindrical portion of the sealing plug. The smaller diameter end of the clamping bolt corresponds to and is in close contact with the inner end face of the cylindrical step of the sealing plug. After the sealing plug and clamping bolt are matched, the clamping bolt is connected to the threaded hole of the tubular specimen via its external threads.

5. The dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens according to claim 4, characterized in that, The sealing plug has an internal through hole. The other end of the lower sealing plug is connected to one end of the liquid lead-bismuth alloy inlet pipe through the lower through hole in the lower base via a threaded seal. The other end of the upper sealing plug is connected to one end of the liquid lead-bismuth alloy outlet pipe through the upper through hole in the upper base via a threaded seal, thus achieving connection with the second circuit pipeline of the dynamic liquid lead-bismuth alloy. The liquid lead-bismuth alloy inlet pipe and the liquid lead-bismuth alloy outlet pipe are wrapped with armored electric heat tracing and insulation cotton.

6. The dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device for tubular specimens according to claim 4, characterized in that, A thermocouple is attached to the outer surface of the gauge length of the tubular specimen to monitor / control the temperature of the liquid lead-bismuth alloy flowing through the tubular specimen in real time. The tubular specimen is mounted on the fatigue fixture of the fatigue testing machine via an upper base and a lower base. After the tubular specimen is mounted on the fatigue testing machine, a strain extensometer is installed on the outer surface of the gauge length of the tubular specimen. The strain extensometer is connected to the fatigue testing machine to monitor / control the strain of the gauge length of the tubular specimen in real time during the fatigue test. The fitted sealing plug and clamping bolt are installed into the threaded hole of the tubular specimen. By tightening the clamping bolt, the sealing plug is vertically compressed, causing the head of the sealing plug to contact the V-shaped sealing surface of the tubular specimen to form a hard seal. After tightening, a sealing effect is achieved. After the seal is installed, it can achieve a flow rate of 0~4m / s, a temperature of 300~550℃, and an oxygen concentration of saturated oxygen ~10. -8 wt.% Controllable corrosion fatigue test of liquid lead-bismuth alloy.

7. A method of using the tubular specimen dynamic liquid lead-bismuth alloy circuit corrosion fatigue testing device according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) The clamping bolt is fitted onto the sealing plug. The clamping bolt and sealing plug are installed in the threaded holes at both ends of the tubular specimen. The clamping bolt is tightened so that the heads of the upper and lower sealing plugs form a hard seal with the V-shaped sealing surface of the tubular specimen. At the same time, the fatigue fixture of the fatigue testing machine is used to clamp the tubular specimen through the upper and lower bases. (2) The liquid lead-bismuth alloy inlet pipe is connected to the first sealing joint of the second circuit pipe by a thread, and the liquid lead-bismuth alloy outlet pipe is connected to the second sealing joint of the second circuit pipe by a thread, thereby realizing the connection with the dynamic liquid lead-bismuth alloy circuit. (3) The liquid lead-bismuth alloy inlet pipe and liquid lead-bismuth alloy outlet pipe are wrapped with armored electric heat tracing and heat insulation cotton, and heated by power supply; thermocouples are pasted on the surface of the tubular sample, and extensometers are clamped on the tubular sample; (4) The first loop pipeline is wrapped with armored electric heat tracing and insulation cotton, and the power supply and temperature control are set to 400°C. The control cabinet supplies power and controls the temperature of the storage vessel, the first reaction vessel and the second reaction vessel through the line. The liquid lead-bismuth alloy is placed in the storage vessel and heated and the temperature is controlled as the storage vessel melts. The liquid metal electromagnetic pump is powered and a voltage of 150V±30V is applied to make the liquid metal electromagnetic pump run idle and heat the internal pipeline of the liquid metal electromagnetic pump to 400°C. (5) When the temperature of the storage vessel, the loop pipeline, the internal pipeline of the liquid metal electromagnetic pump, the first reaction vessel and the second reaction vessel is >350℃, open the first liquid lead-bismuth alloy valve, close the other liquid lead-bismuth alloy valves, and pass high-purity argon gas through the gas inlet of the storage vessel so that the liquid lead-bismuth alloy in the storage vessel flows into the liquid metal electromagnetic pump along the pipeline, thereby meeting the start-up requirements of the liquid metal electromagnetic pump. (6) Close the inlet of the storage vessel, open the outlet of the storage vessel, depressurize the storage vessel, then close the outlet of the storage vessel, open the first liquid lead-bismuth alloy valve, set the voltage of the liquid metal electromagnetic pump control cabinet to 250V, the liquid lead-bismuth alloy in the pipe begins to flow, the liquid metal flow meter displays the real-time flow rate, and a dynamic liquid lead-bismuth alloy circuit is formed. (7) Open the oxygen control system controller to control the air intake of the oxygen control solenoid valve to achieve oxygen control of the liquid lead-bismuth alloy in the inner cavity of the first reactor; (8) Open the two liquid lead-bismuth alloy valves on the branch circuit leading to the fatigue testing machine, close the first liquid lead-bismuth alloy valve, and the liquid lead-bismuth alloy flows through the tubular specimen, enabling fatigue testing of the tubular specimen in a dynamic liquid lead-bismuth alloy environment. (9) After the fatigue test, turn off the power supply of the liquid metal electromagnetic pump, introduce high-purity argon into the oxygen-controlled mixture inlet, and put the liquid lead-bismuth alloy in the first reaction vessel, the tubular sample, and the second loop pipeline into the second reaction vessel. Then, blow it back into the storage vessel through the pipeline connecting the second reaction vessel and the storage vessel to realize the recovery of liquid lead-bismuth alloy and disassemble the fatigue sample under normal temperature air conditions.

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