Metal cold and hot fatigue testing device in molten salt environment

Abstract

The utility model relates to the technical field of material mechanical property testing, in particular to a metal cold and hot fatigue testing device in a molten salt environment. The device comprises a container device, a cooling device, a cold and hot fatigue device, a push-pull device, a connecting support device and a central control panel, the cold and hot fatigue device enables the test process to be closer to the actual working condition through independent arrangement of a high-temperature area and a low-temperature area, the problems of prolonged test period, unstable temperature and the like caused by frequent heating and cooling can be avoided, and the test efficiency is improved. A cooling device is arranged between the high-temperature area and the low-temperature area, the cooling process is accelerated, and the test period is further shortened; meanwhile, the central control panel is linked with the cooling device, the cold and hot fatigue device and the push-pull device, so that automatic control can be realized, manual intervention is reduced, and the test accuracy and efficiency are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of material mechanical property testing, in particular to a metal cold and hot fatigue testing device in a molten salt environment. Background Art

[0002] Concentrated solar thermal power (CSP) technology is a key clean and renewable energy technology that efficiently converts solar energy into electricity, garnering global attention. However, CSP technology utilizes extensive amounts of molten salt for heat transfer and storage, and requires long-term rapid temperature regulation. This poses a risk of thermal fatigue and fracture to equipment components in contact with the molten salt. Therefore, testing the fatigue resistance of structural materials in a molten salt environment provides a theoretical basis and scientific guidance for the design, selection, maintenance, and replacement of high-temperature molten salt contact materials in CSP power plants.

[0003] Thermal fatigue devices suitable for molten salt environments typically utilize traditional thermal fatigue testing methods, such as high-temperature cycling tests and high-temperature alternating stress tests. While these methods can simulate the thermal fatigue effects of molten salt environments, they suffer from the following drawbacks: 1. Long test cycles: Traditional thermal fatigue testing methods require a long time to complete, which can affect test efficiency; 2. High costs: Traditional thermal fatigue testing methods require a large amount of equipment and materials, resulting in high costs; 3. Complex operations: Traditional thermal fatigue testing methods require specialized technicians, making them difficult to operate.

[0004] For example, Chinese patent CN114674694A discloses a material fatigue performance testing system in a high-temperature molten salt environment. The system provides a high-temperature molten salt environment for the test sample by transporting heated molten salt into the space of the test sample. The system only controls the temperature and power of the molten salt heating, but does not control or monitor the sample environment. This results in low measurement accuracy, affecting the accuracy of the measurement results. The molten salt needs to be continuously heated for circulation, which requires replacement and maintenance of equipment and materials, increasing system operating costs. In addition, there is a problem that only high-temperature molten salt environment treatment does not conform to the actual working conditions of actual hot and cold alternation. Chinese patent CN117250144A discloses an atmosphere-controllable high-temperature molten salt corrosion-thermal-mechanical fatigue testing device and method, in which a single temperature control component of the device is used to quickly heat and cool the molten salt and sample. Heating and cooling by the single temperature control component takes a long time, resulting in a long test cycle. Frequent changes in temperature settings can lead to unstable temperature control, which in turn causes low measurement accuracy and complex operation.

[0005] Therefore, special experimental equipment is needed that can work stably under extremely cold and hot conditions for a long time and simulate the actual temperature changes of molten salt in the pipeline, so as to simulate the actual working conditions of thermal fatigue tests in molten salt environments for a long time. Utility Model Content

[0006] To solve the above technical problems, the present application provides a metal thermal fatigue testing device in a molten salt environment. The specific technical solution is as follows:

[0007] A metal thermal fatigue testing device in a molten salt environment comprises: a container device, a cooling device, a thermal fatigue device, a push-pull device and a central control panel, wherein the thermal fatigue device comprises a high-temperature region device and a low-temperature region device, and the high-temperature region device and the low-temperature region device are both hollow tubular structures. The cooling device is fixed between the high-temperature region device and the low-temperature region device, and the push-pull device is fixedly connected to the container device. The container device and part of the push-pull device can move back and forth inside the high-temperature region device and inside the low-temperature region device. The central control panel comprises a control system, and the cooling device, the high-temperature region device, the low-temperature region device and the push-pull device are electrically connected to the control system of the central control panel.

[0008] Furthermore, it also includes a connecting support device, which consists of a circular disc and multiple long cylinders. The long cylinders are vertically fixed on the semicircular circumference of the circular disc. The push-pull device is vertically fixed to the center of the circular disc via bolts. The long cylinder is located in the lower semicircular part of the circular disc. The push-pull device and the long cylinder are respectively fixed on both sides of the circular disc. The container device is placed on the connecting support device.

[0009] Furthermore, the container device includes a molten salt body, a molten salt cavity and a cavity cover. The molten salt body is a hollow structure, the molten salt cavity is a hollow cavity inside the molten salt body, and the top of the molten salt body is open, and the structure of the cavity cover matches the opening.

[0010] Furthermore, the container device is a cylindrical structure inverted 90 degrees.

[0011] Furthermore, the molten salt body and the cavity cover are made of GH625 alloy.

[0012] Furthermore, the cooling device includes an air compressor, a high-pressure air pipe, a hollow cooler and a solenoid valve. The hollow cooler is a tubular structure with openings at both ends, and the wall of the tubular structure is hollow, or the hollow cooler is a spiral coil, and the coil is hollow; the solenoid valve is provided with a switch and is connected to the air compressor, the air compressor is connected to the high-pressure air pipe, and the high-pressure air pipe is connected to the hollow cooler. The hollow cooler is located in the middle position of the high-temperature area device and the low-temperature area device and is coaxial with the high-temperature area device and the low-temperature area device. The inside of the hollow cooler is provided with evenly distributed air holes, and the inner diameter of the hollow cooler is larger than the maximum outer diameter of the container device.

[0013] Furthermore, the length of the hollow cooler is not less than the length of the container device.

[0014] Furthermore, the high-temperature zone device includes a high-temperature nickel-chromium wire heating coil, a high-temperature zone hollow quartz tube and a heating power supply, and the high-temperature nickel-chromium wire heating coil is wound on the high-temperature zone hollow quartz tube. The low-temperature zone device includes a low-temperature nickel-chromium wire heating coil, a low-temperature zone hollow quartz tube and a heating power supply, and the low-temperature nickel-chromium wire heating coil is wound on the low-temperature zone hollow quartz tube.

[0015] Furthermore, the outer layer of the high-temperature nickel-chromium wire heating coil is sequentially provided with two layers of heat-insulating materials and a metal insulation layer, and the two layers of heat-insulating materials are refractory bricks and heat-insulating foam respectively.

[0016] Furthermore, the push-pull device includes a push-pull rod, a pulley and a slide rail. Part of the push-pull rod passes through the high-temperature area device or the low-temperature area device and is connected to the container device. The pulley is fixed under the push-pull rod, and the slide rail is fixed on the plane below the pulley.

[0017] The beneficial effects of the utility model are as follows:

[0018] 1. The device of the utility model is provided with a high temperature zone and a low temperature zone, so that the test process is closer to the actual working conditions. The material can be subjected to a long-term and multiple thermal fatigue test in a molten salt environment, thereby further studying the fatigue resistance of the material in the molten salt environment and effectively solving the problem of lack of a suitable container to test hot and cold fatigue in a molten salt environment.

[0019] 2. In the device of the present invention, the high-temperature zone and the low-temperature zone are separated and set independently. By setting the moving speed and distance of the push-pull device, the container device, that is, the sample in the molten salt environment, can be stably circulated between the high-temperature zone and the low-temperature zone, thereby ensuring the repeatability and reliability of the test results; in addition, since there is no need to continuously heat up and cool down, the temperatures of the high-temperature zone and the low-temperature zone remain constant, the cycle can be significantly shortened, and large temperature fluctuations during the continuous heating and cooling process are avoided, which is conducive to improving the accuracy of the test results.

[0020] 3. The container device of the present invention can ensure a relatively uniform temperature in the cavity by using a molten salt body and a molten salt cavity, thereby ensuring that the sample is subjected to a uniform temperature effect during the test, thereby further ensuring the accuracy of the test.

[0021] 4. The utility model uses a cooling device composed of an air compressor, a hollow cooler and a solenoid valve to quickly cool the sample in the process of moving it from a high-temperature area to a low-temperature area, shortening the cooling time and cycle time and improving the test efficiency.

[0022] 5. Using the test device of the present invention, the experimenter can set parameters such as the temperature range and heating time required by the material to adapt to different materials and different testing requirements; through the linkage of the central control panel and the push-pull device, automatic control can be achieved, reducing manual intervention and improving the accuracy and efficiency of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following further describes the embodiments of the present invention with reference to the accompanying drawings, wherein:

[0024] Figure 1 A physical diagram of a device for testing metal thermal fatigue in a molten salt environment is shown;

[0025] Figure 2 A schematic diagram of part of a device for testing metal thermal fatigue in a molten salt environment is shown;

[0026] Figure 3 A schematic diagram of part of a device for testing metal thermal fatigue in a molten salt environment is shown;

[0027] Figure 4 A schematic diagram showing a container device and a connecting support device of a metal thermal fatigue testing device in a molten salt environment according to the present invention is shown;

[0028] Among them, 1. Container device; 2. Cooling device; 3. Hot and cold fatigue device; 4. High-temperature nickel-chromium wire heating coil; 5. Low-temperature nickel-chromium wire heating coil; 6. Push-pull device; 7. Central control panel; 8. Connecting support device; 9. Disc; 10. Long cylinder; 11. Molten salt body; 12. Molten salt chamber; 13. Chamber cover; 14. Hollow cooler; 15. Push-pull rod; 16. Pulley; 17. Electronic control. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] As attached Figure 1-4 As shown, a metal thermal fatigue testing device in a molten salt environment includes: a container device 1, a cooling device 2, a thermal fatigue device 3, a push-pull device 6, a connecting support device 8 and a central control panel 7.

[0031] The hot and cold fatigue device 3 includes a high-temperature area device and a low-temperature area device. Both the high-temperature area device and the low-temperature area device are hollow tubular structures. The high-temperature area device includes a high-temperature nickel-chromium wire heating coil 4, a high-temperature area hollow quartz tube and a heating power supply. The high-temperature nickel-chromium wire heating coil 4 is wound on the high-temperature area hollow quartz tube. The outer layer of the high-temperature nickel-chromium wire heating coil 4 is provided with two layers of thermal insulation materials: refractory bricks and thermal insulation foam. The outermost layer is wrapped by a metal insulation layer to form a hollow heating cavity. This structure can effectively prevent heat loss and maintain the stability of the heating temperature; the low-temperature area device includes a low-temperature nickel-chromium wire heating coil 5, a low-temperature area hollow quartz tube and a heating power supply. The low-temperature nickel-chromium wire heating coil 5 is wound on the low-temperature area hollow quartz tube.

[0032] The cooling device 2 is fixed between the high temperature area device and the low temperature area device. The cooling device includes an air compressor, a high pressure air pipe, a hollow cooler 14 and a solenoid valve. The hollow cooler 14 is a tubular structure with two ends open. The wall of the tubular structure is hollow. Figure 3 The hollow cooler may also be a spiral coil, and the coil is hollow; the solenoid valve is provided with a switch and is connected to the air compressor, and the solenoid valve is arranged at the outer end of the air compressor, and the switch of the air compressor is controlled by opening and closing the solenoid valve, and the air compressor is connected to the high-pressure air pipe, and the high-pressure air pipe is connected to the hollow cooler 14, and the hollow cooler 14 is located in the middle position of the high-temperature area device and the low-temperature area device and is coaxial with the high-temperature area device and the low-temperature area device. The inside of the hollow cooler 14 is provided with evenly distributed air holes, and the air compressor compresses the air, connects it to the high-pressure air pipe through the adapter, and transports the gas to the high-pressure air pipe, and then transmits it to the hollow cooler 14 by the high-pressure air pipe, and then sprays the high-pressure gas evenly on the surface of the container device through the air holes in the hollow cooler 14, so as to evenly cool the molten salt and the sample; the inner diameter of the hollow cooler is larger than the maximum outer diameter of the container device, and the container device can pass through the hollow cooler. In addition, the length of the hollow cooler is not less than the length of the container device, so that the container device and the sample therein can be fully cooled. Due to the design of air compressor and high-pressure air pipe, the cooling efficiency is greatly improved, which can remove the heat in the molten salt more quickly, thereby extending the service life of the equipment.

[0033] The push-pull device 6 includes a push-pull rod 15, a pulley 16 and a slide rail. Part of the push-pull rod 15 passes through the high-temperature area device or the low-temperature area device and is fixedly connected to the connecting support device 8 via bolts. The pulley 16 is fixed below the push-pull rod 15, and the slide rail is fixed on the plane below the pulley 16. The connecting support device 8 consists of a disc 9 and a plurality of long cylinders 10. The long cylinders 10 are vertically fixed on the semicircular circumference of the disc 9. The push-pull rod 15 of the push-pull device 6 is vertically fixed to the center of the disc 9 via bolts. The long cylinder 10 is located in the lower semicircular part of the disc 9. The push-pull device 6 and the long cylinder 10 are respectively fixed on both sides of the disc 9. The cylindrical container device 1 is placed on the connecting support device 8 and supported and limited by the long cylinder 10. The push-pull device 6 slides through the pulley 16, driving the container device 1 to move back and forth inside the high-temperature area device and the low-temperature area device. The central control panel 7 includes a control system. The cooling device 2, high-temperature area device, low-temperature area device and push-pull device 6 are connected to the control system electronic control 17 of the central control panel 7. The control device of the central control panel 7 controls the heating of the high-temperature nickel-chromium wire heating coil 4 and the low-temperature nickel-chromium wire heating coil 5, the start-up of the cooling device 2 and the movement of the push-pull device 6 via the electronic control 17.

[0034] The cylindrical container device 1 includes a molten salt body 11, a molten salt chamber 12, and a chamber cover 13. The molten salt body 11 is a hollow structure, and the molten salt chamber 12 is a hollow cavity inside the molten salt body. At the same time, the molten salt body 11 has an opening on the top. The structure of the chamber cover 13 matches the opening and is a rectangular cover plate with the same size as the opening. When the container device 1 is placed on the connecting support device 8, it is placed upside down 90°. The molten salt body 11 and the chamber cover 13 are made of GH625 alloy, which effectively avoids the influence of electrochemical corrosion on the molten salt chamber. The molten salt, sample, and calibration sample are all placed in the molten salt chamber 12. The container device can be customized to replace the size and shape of the container device according to the sample conditions to be tested.

[0035] The central control panel 7 includes a power switch, heating on / off key, alarm indicator, alarm cancellation button, process editor, system parameter setter, historical data recorder, temperature curve instrument, alarm recorder, and operation recorder. The functions of each module are as follows: Power switch: Turn on the power switch after the equipment circuit breaker is turned on; Equipment startup: After power is on and there are no faults, turn on the heating on / off key to start heating. If there is a fault alarm, the equipment will not heat up and the cause of the fault must be corrected; Heating stop: Press this button to stop heating while the equipment is heating; Alarm cancellation button: Press this button to cancel the alarm; Process editor: Includes settings for high and low temperature zones, push-pull mechanism movement rate, heating rate, cooling mechanism operating temperature, stop position, and cycle count; System parameters: Allows setting of upper and lower temperature limits and output power limit; Historical data: Records the parameters set for each experiment; Temperature curve: The horizontal axis is time and the vertical axis is furnace temperature, accurately reflecting furnace temperature stability; Alarm log: Allows viewing the time of each alarm. Each control system module is physically and electrically connected to the cooling mechanism and thermal fatigue device via pre-set circuitry.

[0036] Based on the above-mentioned metal thermal fatigue test device in a molten salt environment, the following is a specific metal thermal fatigue test in a molten salt environment, including the following steps:

[0037] Step S1: Weld a K-type thermocouple to a calibration specimen with the same material and specifications as the sample, and connect it to a temperature measuring potentiometer;

[0038] Step S2: Place the sample and calibration sample in the container device, and try to ensure that the calibration sample is placed in the middle to ensure that the measured temperature is sufficiently accurate; the calibration sample must be made of the same material specifications as the experimental sample, for example, the calibration sample and the experimental sample are both GH625 alloy;

[0039] Step S3: Turn on the power, close the power circuit breaker, and turn on the air compressor of the cooling device to ensure that the air compressor works normally;

[0040] Step S4: Turn on the power switch of the central control panel to start the power supply and start the hot and cold fatigue test device to work;

[0041] Step S5: Calibrate the device using a calibration sample: push the push-pull device to push the container device into the high-temperature area device, use a thermocouple to detect the temperature of the calibration sample, and when the temperature of the calibration sample reaches the high-temperature set temperature, record the high-temperature heating power and heating time of the calibration sample; push the container device into the low-temperature area device, use a thermocouple to detect the temperature of the calibration sample, and when the temperature of the calibration sample reaches the low-temperature set temperature, record the low-temperature heating power and heating time of the calibration sample;

[0042] Step S6: Set the temperature, heating rate, heating power, heating time, moving speed and distance of the high-temperature zone device and the low-temperature zone device, and the start and stop conditions of the push-pull device in the control system of the central control panel, and set the operation program of the control system: the high-temperature zone temperature is set to 580-600℃, the low-temperature zone is set to 50-60℃, the heating rate is 6-8℃ / s, the moving speed of the push-pull device is 600-800mm / min, move to the high-temperature zone 750-800mm away from the starting point, and then move from the high-temperature zone at a speed of 600-800mm / min Go to the starting point, pass through the cooling device at the starting point, turn on the cooling device to cool the sample to 300-400℃, then move to the low temperature zone at a speed of 600-800mm / min, and finally return to the starting point from the low temperature zone to complete a complete cycle, a total of 180-220 cycles. When the calibration sample temperature reaches the set value in the high temperature zone or the low temperature zone, it will move away again; set the operating program of the control system, set the manual push-pull device on the central control panel, manually adjust the push-pull device to the starting point, and then switch to the automatic push-pull device. Click to start running and heating, and the equipment will start to run according to the set parameters.

[0043] Step S7: Press the start button to perform fatigue test. During the test, monitor the temperature of the calibration sample. When the temperature of the calibration sample does not match the set temperature, recalibrate it and adjust the parameters until the temperature is the same as the set temperature before continuing the fatigue test.

[0044] After the above hot and cold fatigue treatments are carried out by this device, the surface of the sample is observed to see if there are cracks or strength and hardness tests are carried out.

[0045] The test process of this method is closer to actual working conditions, and can conduct long-term and multiple thermal fatigue tests on materials in a molten salt environment, thereby further studying the fatigue resistance of materials in a molten salt environment.

[0046] Some exemplary embodiments of the present invention are described above. It will be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. The features in these embodiments can be recombined in an appropriate manner, and the solutions obtained thereby are still within the scope of protection claimed by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making any creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A metal thermal fatigue testing device in a molten salt environment, characterized in that: include: A container device, a cooling device, a heat and cold fatigue device, a push-pull device and a central control panel, wherein the heat and cold fatigue device includes a high-temperature area device and a low-temperature area device, and the high-temperature area device and the low-temperature area device are both hollow tubular structures. The cooling device is fixed between the high-temperature area device and the low-temperature area device, and the push-pull device is fixedly connected to the container device. The container device and part of the push-pull device can move back and forth inside the high-temperature area device and the low-temperature area device. The central control panel includes a control system, and the cooling device, the high-temperature area device, the low-temperature area device and the push-pull device are electrically connected to the control system of the central control panel.

2. The metal thermal fatigue testing device in a molten salt environment according to claim 1, characterized in that: It also includes a connecting support device, which consists of a circular disc and multiple long cylinders. The long cylinders are vertically fixed on the semicircular circumference of the circular disc. The push-pull device is vertically fixed to the center of the circular disc via bolts. The long cylinder is located in the lower semicircular part of the circular disc. The push-pull device and the long cylinder are respectively fixed on both sides of the circular disc. The container device is placed on the connecting support device.

3. The metal thermal fatigue testing device in a molten salt environment according to claim 1, characterized in that: The container device includes a molten salt body, a molten salt cavity and a cavity cover. The molten salt body is a hollow structure. The molten salt cavity is a hollow cavity inside the molten salt body. The molten salt body has an opening on top, and the cavity cover has a structure that matches the opening.

4. The metal thermal fatigue testing device in a molten salt environment according to claim 3, characterized in that: The container device is a cylindrical structure inverted by 90 degrees.

5. The metal thermal fatigue testing device in a molten salt environment according to claim 1, characterized in that: The cooling device includes an air compressor, a high-pressure air pipe, a hollow cooler and a solenoid valve: the hollow cooler is a tubular structure with openings at both ends, the wall of the tubular structure is hollow, or the hollow cooler is a spiral coil, and the coil is hollow; the solenoid valve is provided with a switch and is connected to the air compressor, the air compressor is connected to the high-pressure air pipe, and the high-pressure air pipe is connected to the hollow cooler, the hollow cooler is located in the middle position of the high-temperature area device and the low-temperature area device and is coaxial with the high-temperature area device and the low-temperature area device, the inside of the hollow cooler is provided with evenly distributed air holes, and the inner diameter of the hollow cooler is larger than the maximum outer diameter of the container device.

6. The metal thermal fatigue testing device in a molten salt environment according to claim 5, characterized in that: The length of the hollow cooler is not less than the length of the container device.

7. The metal thermal fatigue testing device in a molten salt environment according to claim 1, characterized in that: The high-temperature zone device includes a high-temperature nickel-chromium wire heating coil, a high-temperature zone hollow quartz tube and a heating power supply, and the high-temperature nickel-chromium wire heating coil is wound on the high-temperature zone hollow quartz tube. The low-temperature zone device includes a low-temperature nickel-chromium wire heating coil, a low-temperature zone hollow quartz tube and a heating power supply, and the low-temperature nickel-chromium wire heating coil is wound on the low-temperature zone hollow quartz tube.

8. The metal thermal fatigue testing device in a molten salt environment according to claim 7, characterized in that: The outer layer of the high-temperature nickel-chromium wire heating coil is sequentially provided with two layers of heat-insulating materials and a metal insulation layer, wherein the two layers of heat-insulating materials are refractory bricks and heat-insulating foam respectively.

9. The metal thermal fatigue testing device in a molten salt environment according to claim 1, characterized in that: The push-pull device includes a push-pull rod, a pulley and a slide rail. Part of the push-pull rod passes through the high-temperature area device or the low-temperature area device and is connected to the container device. The pulley is fixed below the push-pull rod, and the slide rail is fixed on the plane below the pulley.

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