A device and method for testing the axial strength of a pipe at ultra-high temperatures

Abstract

The application provides a kind of pipe material ultrahigh temperature axial strength testing device and method, the pipe material ultrahigh temperature axial strength testing device includes heating system, sample clamping system, vacuum system, main machine loading system and temperature measurement and control system.Two pipe material bonding sleeves are provided with outer lifting shoulder, and are used for bonding the two ends of axial tensile sample by high temperature adhesive respectively, and are connected with main machine loading system by outer lifting shoulder.Two adapters in main machine loading system are connected with the outer lifting shoulder of two pipe material bonding sleeves respectively, and main machine loading system is used for axial strength test to axial tensile sample and records and analyzes test data.The application connects the two ends of axial tensile sample with two pipe material bonding sleeves by high temperature adhesive, and sets outer lifting shoulder on pipe material bonding sleeve to connect with adapter in main machine loading system, to solve the problem of how to avoid sample damage caused by traditional sample clamping mode.

Description

Technical Field

[0001] This application belongs to the field of ultra-high temperature mechanical property testing technology, specifically relating to an ultra-high temperature axial strength testing device and method for pipes. Background Technology

[0002] Ceramics and ceramic composites possess excellent comprehensive properties such as high melting point, low mass, good high-temperature strength, and high thermal conductivity, and have been widely used in important fields such as aerospace and energy. As a high-temperature structural material, its tensile strength under ultra-high temperature conditions determines the upper limit of the stress that the material can withstand in the axial direction, which plays a decisive role in its safe use. Therefore, it is urgent to evaluate the mechanical properties of such materials under high-temperature conditions.

[0003] However, as a special type of structural component, this type of tubing cannot be subjected to the traditional hard friction contact method used with metal materials during axial tension. The clamping principle of this method relies on lateral compression of the material, causing slight deformation to provide axial friction force, thus enabling force transmission with the testing machine. However, this type of material has poor deformation capacity, and hard compression damages the tubing, creating weak points that lead to fracture at the clamping section during tension, ultimately resulting in tensile failure. Furthermore, ceramics and ceramic composites have poor weldability, making it impossible to connect them using cylindrical threads welded to the ends of stainless steel metal tubes. Simultaneously, these tubing types cannot be connected using longitudinally cut arc-shaped specimens or pins with holes at both ends, as this easily introduces processing defects or disrupts the continuity of the composite fibers, making the test results inaccurate to represent the inherent strength of the tubing. Moreover, maintaining the clamping force at the specimen ends without attenuation under ultra-high temperature testing environments is also one of the main challenges in the axial testing of ceramic and ceramic composite tubing. Summary of the Invention

[0004] In view of this, this application provides a device and method for testing the axial strength of pipes at ultra-high temperature. By using a high-temperature adhesive to connect both ends of the axial tensile specimen to two pipe bonding sleeves respectively, and by setting an outer shoulder on the pipe bonding sleeve to connect to the adapter in the main loading system, the problem of specimen damage caused by traditional specimen clamping methods can be solved.

[0005] This application provides a device for testing the axial strength of pipes at ultra-high temperatures. The device includes a heating system, a sample clamping system, a vacuum system, a main loading system, and a temperature control system. The sample clamping system includes two pipe bonding sleeves. Each sleeve has an outer shoulder, used to bond the two ends of an axially tensile sample with a high-temperature adhesive, and connected to the main loading system via the outer shoulders. The heating system is installed outside the axially tensile sample for heating it. The vacuum system is installed outside the heating system to provide a vacuum environment for the sample. The temperature control system monitors and controls the heating temperature applied to the sample. Two adapters in the main loading system are connected to the outer shoulders of the two pipe bonding sleeves, and the main loading system is used to perform axial strength testing on the sample and record and analyze the test data.

[0006] In one specific embodiment of this application, the ultra-high temperature axial strength testing device for the pipe further includes a cooling system. The cooling system includes a water-cooled jacket, an outlet pipe, an inlet pipe, and the water cooling system itself. Both the outlet and inlet pipes are connected to the water cooling system. The water-cooled jacket is installed outside the pipe's bonding sleeve. The water-cooled jacket has an inlet, an outlet, and an internal flow channel, with the inlet and outlet connected to the outlet and inlet pipes of the cooling system, respectively. Low-temperature water within the water cooling system circulates in and out of the internal flow channel of the water-cooled jacket.

[0007] In one specific embodiment of this application, the water-cooling jacket has an inner circle and an outer square structure.

[0008] In one specific embodiment of this application, the heating system includes an induction heating sleeve and a spiral induction coil. The spiral induction coil is disposed on the outside of the induction heating sleeve. The induction heating sleeve is used to cover the outside of the portion of the axially tensile specimen not covered by the tubular adhesive sleeve.

[0009] In one specific embodiment of this application, the heating system further includes heat insulation plugs. A heat insulation plug is located at each of the upper and lower ends of the induction heating sleeve.

[0010] In one specific embodiment of this application, the vacuum system includes a vacuum furnace body, a vacuum piping system, and a vacuum unit. The vacuum furnace body is installed outside the heating system. The vacuum piping system is connected to the side of the vacuum furnace body. The vacuum unit is equipped at the end of the vacuum piping system. The vacuum furnace body is connected to the base of the stretching machine via a fixed bracket.

[0011] In one specific embodiment of this application, the main loading system includes a lower main loading rod, an upper main loading rod, an upper crossbeam of the stretching machine, and a load-bearing support guide rod. The upper main loading rod connects the upper end of the pipe bonding sleeve to the upper crossbeam of the stretching machine. The lower main loading rod connects the lower end of the pipe bonding sleeve to the base of the stretching machine. The upper crossbeam of the stretching machine is supported on the base of the stretching machine via the load-bearing support guide rod. An upper adapter on the upper main loading rod connects to the outer shoulder of the upper pipe bonding sleeve. A lower adapter on the lower main loading rod connects to the outer shoulder of the lower pipe bonding sleeve.

[0012] In one specific embodiment of this application, the material of the induction heating sleeve is graphite.

[0013] In one specific embodiment of this application, the temperature measurement and control system includes a non-contact laser measuring instrument. A small hole is provided in the middle of the induction heating sleeve. The small hole allows the laser temperature measurement and control optical path of the non-contact laser measuring instrument to pass through.

[0014] The second aspect of this application provides a method for testing the ultra-high temperature axial strength of pipes, which is performed using the ultra-high temperature axial strength testing device for pipes provided in the first aspect of this application. The method includes the following steps.

[0015] Step S1: Provide an axial tensile specimen.

[0016] Step S2: The two pipe bonding sleeves are bonded to the two ends of the axial tensile specimen using high-temperature adhesive, and connected to the adapter in the main loading system through the outer shoulder of the pipe bonding sleeve.

[0017] Step S3: Heat the axially tensile specimen using a heating system, and monitor and control the temperature of the axially tensile specimen using a temperature measurement and control system.

[0018] Step S4: The main loading system performs axial strength testing on the axially tensile specimen and records and analyzes the test data.

[0019] The beneficial effects of the technical solution in this application are as follows: 1. The two ends of the axial tensile specimen are connected to two pipe bonding sleeves respectively. The two pipe bonding sleeves are bonded to the axial tensile specimen with high temperature adhesive. The two pipe bonding sleeves can provide clamping during axial tension. This method can avoid material damage caused by hard contact, similar to the clamping of metal pipes.

[0020] 2. The ultra-high temperature axial strength testing device for this pipe is simple and highly operable. It can provide heating above 1700℃, material vacuum protection, and axial strength testing capabilities for many thin-walled, small-diameter pipes with high melting points, ceramics, and ceramic composites during axial tensile testing. It can meet the requirements of axial soft clamping of pipes under ultra-high temperature conditions and obtain ultra-high temperature axial strength data of pipes, avoiding the sample damage problem caused by traditional metal pipe extrusion clamping methods. Attached Figure Description

[0021] Figure 1 The diagram shown is a structural schematic of an ultra-high temperature axial strength testing device for pipes provided in an embodiment of this application.

[0022] Figure 2 The diagram shown is a partial assembly schematic of a pipe axial strength testing device provided in an embodiment of this application.

[0023] Figure 3 The diagram shown is a schematic diagram of the water-cooled jacket in an ultra-high temperature axial strength testing device for pipes provided in an embodiment of this application.

[0024] Figure 4 The diagram shown is a structural schematic of the pipe bonding sleeve in an ultra-high temperature axial strength testing device for pipes provided in an embodiment of this application.

[0025] Figure 5 The diagram shown is a schematic representation of the state of a pipe axial strength testing device according to an embodiment of this application during an ultra-high temperature axial strength test.

[0026] In the figure, 1-axial tensile specimen; 2-induction heating sleeve; 3-sleeve orifice; 4-heat insulation plug; 5-spiral induction coil; 6-water cooling jacket; 7-pipe bonding sleeve; 8-vacuum furnace body; 9-fixed bracket; 10-vacuum piping system; 11-vacuum unit; 12-water outlet pipe; 13-water inlet pipe; 14-water cooling system; 15-lower connecting rod; 16-upper connecting rod; 17-tensile machine upper crossbeam; 18-load-bearing support guide rod; 19-water inlet; 20-water outlet; 21-internal flow channel; 22-inner circle; 23-locating pin; 24-gap; 25-thread; 26-outer shoulder; 27-outer sleeve. Detailed Implementation

[0027] Based on the above difficulties, this application presents an embodiment of a device for testing the axial tensile properties of ceramic and ceramic composite pipes at ultra-high temperatures. It completes the axial tensile test research of such pipes under ultra-high temperature vacuum conditions, providing support for the high-temperature mechanical property testing of ceramic and ceramic composite pipes and filling the gap in the domestic high-temperature vacuum tensile property testing of ceramic and ceramic composite pipes.

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

[0029] At least one embodiment of this application provides a device for testing the ultra-high temperature axial strength of pipes, with reference to... Figures 1 to 4 The ultra-high temperature axial strength testing device for this pipe includes a heating system, a sample clamping system, a vacuum system, a main loading system, and a temperature control system. The sample clamping system includes two pipe bonding sleeves 7. Each of the two pipe bonding sleeves 7 has an outer shoulder 26, used to bond the two ends of the axial tensile sample 1 with a high-temperature adhesive, and connected to the main loading system via the outer shoulder 26. The heating system is installed outside the axial tensile sample 1 for heating it. The vacuum system is installed outside the heating system for providing a vacuum environment for the axial tensile sample 1. The temperature control system monitors and controls the heating temperature of the axial tensile sample 1. In the main loading system, two adapters connect to the outer shoulders 26 of the two pipe bonding sleeves 7, respectively. The main loading system is used to perform axial strength testing on the axial tensile sample 1 and record and analyze the test data.

[0030] In the above embodiment, both ends of the axial tensile specimen 1 are connected to two pipe bonding sleeves 7, which are bonded to the axial tensile specimen 1 with a high-temperature adhesive. The two pipe bonding sleeves 7 provide clamping during axial tension, avoiding material damage caused by hard contact, similar to that caused by clamping metal pipes. Furthermore, this ultra-high temperature axial strength testing device for pipes is simple and highly operable, providing a testing device and method for axial ultra-high temperature tensile testing of numerous high-melting-point, small-diameter ceramic pipes, and obtaining ultra-high temperature axial strength data for the pipes.

[0031] For example, refer to Figure 4 The pipe bonding sleeve 7 includes a locating pin 23, an outer shoulder 26, and an outer sleeve 27. The locating pin 23 is connected to the base of the outer sleeve 27 by a thread 25. The gap 24 between the sleeve wall of the outer sleeve 27 and the locating pin 23 is used for inserting the axial tensile specimen 1. The outer shoulder 26 refers to the right-angled frustum formed by the outer sleeve 27 downwards and the bottom surface; this right-angled frustum can be hung on the adapter.

[0032] In at least one embodiment of this application, reference is made to Figure 1 , Figure 2 and Figure 3The ultra-high temperature axial strength testing device for the pipe also includes a cooling system. The cooling system comprises a water-cooled jacket 6, an outlet pipe 12, an inlet pipe 13, and a water-cooling system 14. Both the outlet pipe 12 and the inlet pipe 13 are connected to the water-cooling system 14. The water-cooled jacket 6 is installed outside the pipe bonding sleeve 7. The water-cooled jacket 6 has an inlet 19, an outlet 20, and an internal flow channel 21. The inlet 19 and the outlet 20 are respectively connected to the outlet pipe 12 and the inlet pipe 13 of the cooling system. Low-temperature water within the water-cooling system 14 circulates into and out of the internal flow channel 21 of the water-cooled jacket 6.

[0033] It should be noted that the water cooling system 14 can also be called a cooling water tank. The main loading system can also be called a testing machine. The water inlet 19 can also be called a cold end water inlet threaded connection. The water outlet 20 can also be called a hot end water outlet threaded connection. The inner diameter of the water cooling jacket 6 matches the outer diameter of the pipe bonding sleeve 7. For example, the inner diameter of the water cooling jacket 6 is slightly larger than the outer circumference diameter of the pipe bonding sleeve 7, allowing the pipe bonding sleeve 7 to pass through freely.

[0034] In the above embodiments, by setting the low-temperature water in the water cooling system 14 to flow into and out of the internal flow channel 21 of the water cooling jacket 6, the temperature of the water cooling jacket 6 and the pipe bonding sleeve 7 is carried away. Therefore, the water cooling further reduces the temperature inside the pipe bonding sleeve 7, preventing the high-temperature adhesive connecting the pipe bonding sleeve 7 and the axial tensile sample 1 from softening and failing.

[0035] In at least one embodiment of this application, the water-cooling jacket 6 has an inner circle and an outer square structure.

[0036] In at least one embodiment of this application, reference is made to Figure 1 The heating system includes an induction heating sleeve 2 and a spiral induction coil 5. The spiral induction coil 5 is disposed on the outside of the induction heating sleeve 2. The induction heating sleeve 2 is used to cover the outside of the portion of the axial tensile specimen 1 that is not covered by the tubular adhesive sleeve 7.

[0037] It should be noted that the inner diameter of the induction heating sleeve 2 is slightly larger than the outer diameter of the axial tensile specimen 1, and the inner diameter of the spiral induction coil 5 is slightly larger than the outer diameter of the induction heating sleeve 2.

[0038] In the above embodiments, the induction heating sleeve 2 generates heat under the electromagnetic induction of the spiral induction coil 5 and radiates the heat to the axial tensile specimen 1 inside the pipe bonding sleeve 7, thus achieving the heating purpose. By setting the heating system to rapidly heat the induction heating sleeve 2 using the spiral induction coil 5, the heat from the induction heating sleeve 2 is further rapidly radiated to the surface of the axial tensile specimen 1 within a limited space, confining the temperature radiation space to the effective range of the middle section of the axial tensile specimen 1. This results in low heating energy consumption, high speed, and high energy utilization. In addition, placing the pipe bonding sleeve 7 outside the ultra-high temperature radiation range effectively reduces the operating temperature at the pipe bonding sleeve 7 location.

[0039] In at least one embodiment of this application, reference is made to Figure 1 The heating system also includes heat insulation plugs 4. A heat insulation plug 4 is located at both the upper and lower ends of the induction heating sleeve 2. This arrangement prevents heat from dissipating from the induction heating sleeve 2, thus aiding in the rapid heating of the axially tensile sample 1 within the sleeve.

[0040] In some embodiments, the outer diameter of the heat insulation plug 4 matches the inner diameter of the induction heating sleeve 2. This achieves a better heat insulation and sealing effect.

[0041] For example, the heat insulation plug 4 consists of two symmetrical halves. This design facilitates installation.

[0042] In at least one embodiment of this application, reference is made to Figure 1 The vacuum system includes a vacuum furnace body 8, a vacuum piping system 10, and a vacuum unit 11. The vacuum furnace body 8 is installed outside the heating system. The vacuum piping system 10 is connected to the side of the vacuum furnace body 8. The vacuum unit 11 is equipped at the end of the vacuum piping system 10. The vacuum furnace body 8 is connected to the base of the stretching machine via a fixed bracket 9.

[0043] For example, vacuum unit 11 consists of a mechanical pump and a molecular pump cascaded together.

[0044] In at least one embodiment of this application, reference is made to Figure 1 The main loading system includes a lower main connecting rod 15, an upper main connecting rod 16, an upper crossbeam 17 of the stretching machine, and a load-bearing support guide rod 18. The upper main connecting rod 16 connects the upper pipe bonding sleeve 7 to the upper crossbeam 17 of the stretching machine. The lower main connecting rod 15 connects the lower pipe bonding sleeve 7 to the base of the stretching machine. The upper crossbeam 17 of the stretching machine is supported on the base of the stretching machine via the load-bearing support guide rod 18. An upper adapter on the upper main connecting rod 16 connects to the outer shoulder 26 of the upper pipe bonding sleeve 7. A lower adapter on the lower main connecting rod 15 connects to the outer shoulder 26 of the lower pipe bonding sleeve 7.

[0045] In at least one embodiment of this application, the induction heating sleeve 2 is made of graphite. This enables induction heating to temperatures above 1700°C.

[0046] In at least one embodiment of this application, the temperature measurement and control system includes a non-contact laser measuring instrument. A small hole 3 is provided in the middle of the induction heating sleeve 2. The small hole 3 is used for the passage of the laser temperature measurement and control optical path of the non-contact laser measuring instrument.

[0047] It should be noted that the non-contact laser measuring instrument can also be called a laser emitter for temperature measurement. The sleeve aperture 3 can also be called an optical path aperture. For example, the aperture of the sleeve aperture 3 is 5mm.

[0048] High-temperature adhesives can also be called high-temperature glues. The maximum temperature a high-temperature adhesive can withstand is no less than 600℃. The ultra-high temperature axial strength testing device for this pipe can reach a test temperature of 1700℃, but the high-temperature adhesive does not need to reach such a high temperature. This is due to three clever design features in the device: 1. A water-cooling jacket 6 can lower the temperature significantly, even though the test temperature is 1700℃; 2. The heating zone of the heating system does not include the adhesive area of ​​the induction heating sleeve, so its temperature is lower than the test temperature; 3. A heat-insulating plug 4 prevents some heat from being transferred from the axial tensile specimen 1 to the adhesive joints at both ends. Therefore, the temperature requirement for the high-temperature adhesive can be lowered.

[0049] At least one embodiment of this application also provides a method for testing the ultra-high temperature axial strength of a pipe, which is performed using an ultra-high temperature axial strength testing device for a pipe as described in the above embodiments. (Reference) Figure 5 The method for testing the ultra-high temperature axial strength of this pipe includes the following steps.

[0050] Step S1: Provide an axial tensile specimen 1.

[0051] For example, a ceramic and ceramic composite material tube is machined into an axial tensile specimen 1 with a length of 210 mm using a diamond wire EDM method. The outer diameter of the axial tensile specimen 1 at three positions (top, middle, and bottom) is measured using a measuring tool with an accuracy of not less than 0.02 mm, and the wall thickness at both ends of the axial tensile specimen 1 is measured using a measuring tool with an accuracy of not less than 0.01 mm. The axial tensile specimen 1 is rotated and measured twice at each end. The average value of the outer diameter and wall thickness is used to calculate the original cross-sectional area.

[0052] Step S2: The two pipe bonding sleeves 7 are bonded to the two ends of the axial tensile specimen 1 with high temperature adhesive, and connected to the main loading system through the outer shoulder 26 in the pipe bonding sleeve 7.

[0053] For example, after the measurement is completed, the axial tensile specimen 1 is prepared by a special method for preparing pipe tensile specimens. The axial tensile specimen 1 for testing is prepared by using the pipe bonding sleeve 7 and the high-temperature adhesive.

[0054] Step S3: Heat the axially tensile specimen 1 using a heating system, and monitor and control the temperature of the axially tensile specimen 1 heated by the heating system using a temperature measurement and control system.

[0055] For example, first, insert the prepared axial tensile specimen 1 into the induction heating sleeve 2, and then install the heat insulation plug 4 in sequence; insert the assembled whole component from bottom to top into the spiral induction coil 5 to complete the assembly of the heating system and the axial tensile specimen 1; pass the water-cooling sleeve 6 through the pipe bonding sleeve 7 from the upper and lower ends of the axial tensile specimen 1 respectively, and finally connect the pipe bonding sleeves 7 at both ends of the axial tensile specimen 1 to the upper connecting rod 16 and the lower connecting rod 15 of the main unit respectively to complete the fixed installation of the axial tensile specimen 1 and its accessories. Connect the inlet / outlet water pipes of the water-cooling sleeve 6, adjust the vertical position of the induction heating sleeve 2, align the sleeve hole 3 with the non-contact laser measuring instrument, and ensure that the laser spot of the non-contact laser measuring instrument passes through the sleeve hole 3 and falls on the axial tensile specimen 1.

[0056] Step S4: The main loading system performs axial strength testing on the axially tensile specimen 1 and records and analyzes the test data.

[0057] For example, open the tensile testing software and load the axial tensile specimen 1 to an initial load of 50N using force control. Then, completely unload it, repeating this process 2-3 times. This eliminates any large gaps between the pipe bonding sleeve 7 and the upper connecting rod 16 and lower connecting rod 15 of the main unit, and checks the alignment of the axial tensile specimen 1. Then, close the vacuum furnace body 8 and turn on the mechanical pump of the vacuum unit 11. When the vacuum level reaches approximately 10Pa, turn on the molecular pump of the vacuum unit 11. During this period, set the test parameters such as tensile rate, test temperature, and heating rate. When the vacuum level further decreases to 1×10... -2 At a set pressure of Pa, the force value of the force measuring system is zeroed, and a preload of 50N is set as a constant force holding state. The heating system is turned on to start heating, and after heating to the set test temperature and stabilizing, it is held at that temperature for 15 minutes. Then, the displacement of the crossbeam 17 on the tensile test machine in the software is zeroed, and the tensile test is started until the axial tensile specimen 1 breaks. The load-displacement curve is recorded, and the axial tensile strength is calculated based on the maximum force. After the loading stops, the heating is turned off. After the temperature drops, the molecular pump and mechanical pump are turned off in sequence. After the axial tensile specimen 1 cools to 300℃, the vacuum furnace body 8 is opened and the axial tensile specimen 1 is taken out to observe whether the fracture surface is normal.

[0058] The following is an example illustration of a high-temperature axial strength testing device and method for pipes provided in this application, with reference to specific embodiments.

[0059] Example 1: Taking the axial tensile specimen 1 made of Al2O3 ceramic tube as an example, the nominal outer diameter of the axial tensile specimen 1 is 10.0 mm, the nominal inner diameter is 8.0 mm, the length of the axial tensile specimen 1 cut by diamond wire is 210 mm, and the test temperature is 1500℃.

[0060] The positioning pin 23 inside the tubular bonding sleeve 7, which matches both ends of the axial tensile specimen 1, has a diameter of 7.85 mm and a height of 35 mm. The positioning pin 23 is connected to the base of the outer sleeve 27 by an M8 thread 25, thus assembling the positioning pin 23 and the outer sleeve 27. The gap 24 between the cylinder wall of the outer sleeve 27 and the positioning pin 23 has a width of 1.4 mm, and the outer circumference diameter of the outer wall of the outer sleeve 27 is 18 mm. The tubular bonding sleeve 7 is connected to the main loading system through an outer shoulder 26, wherein the disc diameter of the outer shoulder 26 is 20 mm.

[0061] The induction heating sleeve 2 is made of graphite, with an outer diameter of 50mm, a wall thickness of 10mm, and a length of 160mm. A small hole 3 with a diameter of 5mm is opened in the middle of the sleeve for the optical path of the laser temperature measurement and control system. The upper and lower ends of the induction heating sleeve 2 are sealed by heat insulation plugs 4 to reduce the heat loss from the sleeve. The axial tensile specimen 1 inside the auxiliary tube bonding sleeve 7 is rapidly heated. The heat insulation plug 4 is a disc-shaped shoulder structure with a central through hole, consisting of two symmetrical semicircles. The diameter of the through hole is larger than the diameter of the axial tensile specimen 1, at 16mm, while the diameter of the shoulder inserted into the sleeve is smaller than the inner diameter of the sleeve, at 28mm.

[0062] The inner diameter of the spiral induction coil 5 outside the induction heating sleeve 2 is slightly larger than the outer diameter of the induction heating sleeve 2, which is 80mm. The coil pitch can be adjusted according to the assembly effect. The overall height of the coil is consistent with the length of the sleeve, which is 160mm. The induction heating sleeve 2 generates heat under the electromagnetic induction of the spiral induction coil 5 and radiates the heat to the axial tensile specimen 1 inside the sleeve, thereby heating the axial tensile specimen 1.

[0063] An inner-circle, outer-square water-cooling sleeve 6 is installed on the outside of the pipe bonding sleeve 7. The inner diameter of the water-cooling sleeve 6 is slightly larger than the outer circumference diameter of the pipe bonding sleeve 7, for example, the inner diameter of the water-cooling sleeve 6 is 20mm. It is a cube with an outer contour of 40mm×40mm×35mm, with a water inlet 19 and a water outlet 20 on the left and right sides. The water inlet 19 and the water outlet 20 are M6mm threads and are connected to the water outlet pipe 12 and the water inlet pipe 13 of the cooling system, respectively. The internal cooling circulation hydrodynamic base station is a water-cooling system 14. The low-temperature water in the water-cooling system 14 circulates into and out of the internal flow channel 21 of the water-cooling sleeve 6, thereby removing the temperature of the water-cooling sleeve 6 and the pipe bonding sleeve 7, and preventing the high-temperature adhesive connecting the pipe bonding sleeve 7 and the axial tensile specimen 1 from softening and failing.

[0064] Before bonding the axial tensile specimen 1 to the pipe bonding sleeve 7, the outer diameter was measured once at the lower and middle positions along the axis of the axial tensile specimen 1, and the measurements were 10.14 mm, 10.16 mm, and 10.17 mm, respectively. The wall thickness was measured twice at both ends, and the measurements were 1.07 mm, 1.18 mm, 1.14 mm, and 1.10 mm, respectively. The average values ​​were used to calculate the original cross-sectional area. S 0 =π×(10.157-1.1225)×1.1225=31.86mm 2 .

[0065] After measurement, insert the axial tensile specimen 1 into the positioning pin 23 inside the pipe bonding sleeve 7. Before insertion, high-temperature adhesive can be poured into the gap 24 between the outer sleeve 27 and the positioning pin 23. Rotate the axial tensile specimen 1 to ensure that the high-temperature adhesive is in full contact with the inner and outer walls of the pipe bonding sleeve 7 and the axial tensile specimen 1. After full contact, keep it at room temperature for 12 hours, then keep it at 80℃ for 2 hours, and finally keep it at 150℃ for 2 hours. Cool it to room temperature to complete the preparation. After the axial tensile specimen 1 is prepared, insert it into the induction heating sleeve 2, install the heat insulation plug 4 in sequence, and then insert the spiral induction coil 5 to complete the assembly of the heating system and the axial tensile specimen 1. Pass the water cooling sleeve 6 through the pipe bonding sleeve 7 from the upper and lower ends of the axial tensile specimen 1 respectively. Finally, connect the pipe bonding sleeves 7 at both ends of the axial tensile specimen 1 to the upper connecting rod 16 and the lower connecting rod 15 of the main unit to complete the fixed installation of the axial tensile specimen 1 and its accessories. Connect the inlet / outlet water pipes of the water-cooled jacket 6, adjust the vertical position of the induction heating sleeve 2, align the sleeve hole 3 with the non-contact laser measuring instrument, and ensure that the laser spot of the non-contact laser measuring instrument passes through the sleeve hole 3 and falls on the axial tensile specimen 1.

[0066] Operate the main loading system testing machine, open the tensile testing software on the main loading system, and load the axial tensile specimen 1 to an initial load of 50N using force control. Then, completely unload it, repeating 2-3 times to eliminate large gaps between the main lower connecting rod 15, the main upper connecting rod 16, and the pipe bonding sleeve 7 clamp, and to check the alignment of the axial tensile specimen 1. Then, close the vacuum furnace body 8, turn on the mechanical pump, and when the vacuum degree reaches about 10Pa, turn on the molecular pump. During this period, set the tensile rate to 0.5mm / min, the test temperature to 1700℃, and the heating rate to 75℃ / min~100℃ / min. When the vacuum degree is further reduced to 1×10 -2 At Pa, after zeroing the force value of the force measuring system, a preload of 50N was applied, and the main loading system of the testing machine was set to constant force holding function. The heating power was turned on to start heating, and after heating to the set test temperature and stabilizing, the temperature was held for 15 minutes. Then, the displacement of the crossbeam 17 on the tensile testing machine was zeroed in the software, and the tensile test began until the axial tensile specimen 1 fractured. The load-displacement and temperature-time curves were recorded. The maximum load was... F m =8270N, the circumferential tensile strength was calculated based on the result. R m = F m / S 0 =259.5 MPa. After loading stops, turn off the heating. After the temperature drops, turn off the molecular pump and mechanical pump in sequence. After the axial tensile specimen 1 cools to 300℃, open the vacuum furnace body 8 and take out the axial tensile specimen 1.

[0067] It should be noted that the combination of the technical features in the embodiments of this application is not limited to the combination methods described in the embodiments of this application or the combination methods described in specific embodiments. All technical features described in this application can be freely combined or combined in any way, unless they contradict each other.

[0068] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the term "comprising" only indicates that it includes the explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0069] The above description is merely some specific embodiments of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for testing the axial strength of pipes at ultra-high temperatures, characterized in that, It includes a heating system, a sample clamping system, a vacuum system, a main loading system, and a temperature measurement and control system. The sample clamping system includes two tubular bonding sleeves. Each of the two tubular bonding sleeves has an outer shoulder, which is used to bond the two ends of the axial tensile sample with a high-temperature adhesive and is connected to the main loading system through the outer shoulder. A heating system is installed on the outside of the axial tensile sample for heating the sample. A vacuum system is installed on the outside of the heating system for providing a vacuum environment for the axial tensile sample. A temperature measurement and control system is used to monitor and control the heating temperature of the axial tensile sample by the heating system. Two adapters in the main loading system are connected to the outer shoulders of the two tubular bonding sleeves, respectively. The main loading system is used to perform axial strength testing on the axial tensile sample and record and analyze the test data.

2. The ultra-high temperature axial strength testing device for pipes according to claim 1, characterized in that, It also includes a cooling system. The cooling system includes a water-cooled jacket, an outlet pipe, an inlet pipe, and a water-cooling system. Both the outlet and inlet pipes are connected to the water-cooling system. The water-cooled jacket is installed outside the pipe bonding sleeve. The water-cooled jacket has an inlet, an outlet, and an internal flow channel. The inlet and outlet are connected to the outlet and inlet pipes of the cooling system, respectively. Low-temperature water in the water-cooling system circulates into and out of the internal flow channel of the water-cooled jacket.

3. The ultra-high temperature axial strength testing device for pipes according to claim 2, characterized in that, The water-cooling jacket has an inner circle and an outer square structure.

4. The ultra-high temperature axial strength testing device for pipes according to claim 1, characterized in that, The heating system includes an induction heating sleeve and a spiral induction coil. The spiral induction coil is located outside the induction heating sleeve, which is used to cover the outside of the part of the axial tensile specimen that is not covered by the tube bonding sleeve.

5. The ultra-high temperature axial strength testing device for pipes according to claim 4, characterized in that, The heating system also includes heat insulation plugs, with one heat insulation plug at each of the upper and lower ends of the induction heating sleeve.

6. The ultra-high temperature axial strength testing device for pipes according to claim 4, characterized in that, The material of the induction heating sleeve is graphite.

7. The ultra-high temperature axial strength testing device for pipes according to claim 4, characterized in that, The temperature measurement and control system includes a non-contact laser measuring instrument. The induction heating sleeve has a small hole in the middle, which is used for the passage of the laser temperature measurement and control optical path of the non-contact laser measuring instrument.

8. The ultra-high temperature axial strength testing device for pipes according to claim 1, characterized in that, The vacuum system includes a vacuum furnace body, a vacuum pipeline system, and a vacuum unit. The vacuum furnace body is installed outside the heating system, and the vacuum pipeline system is connected to the side of the vacuum furnace body. The vacuum unit is equipped at the end of the vacuum pipeline system, and the vacuum furnace body is connected to the base of the stretching machine through a fixed bracket.

9. A device for testing the ultra-high temperature axial strength of a pipe according to any one of claims 1 to 8, characterized in that, The main loading system includes a lower main connecting rod, an upper main connecting rod, an upper crossbeam of the stretching machine, and a load-bearing support guide rod. The upper main connecting rod connects the upper pipe bonding sleeve to the upper crossbeam of the stretching machine. The lower main connecting rod connects the lower pipe bonding sleeve to the base of the stretching machine. The upper crossbeam of the stretching machine is supported on the base of the stretching machine via the load-bearing support guide rod. The upper adapter of the upper main connecting rod connects to the outer shoulder of the upper pipe bonding sleeve. The lower adapter of the lower main connecting rod connects to the outer shoulder of the lower pipe bonding sleeve.

10. A method for testing the axial strength of pipes at ultra-high temperatures, characterized in that, The method for testing the ultra-high temperature axial strength of a pipe is performed using the ultra-high temperature axial strength testing device as described in any one of claims 1 to 9, and the method for testing the ultra-high temperature axial strength of a pipe includes: Step S1: Provide an axial tensile specimen; Step S2: The two pipe bonding sleeves are bonded to the two ends of the axial tensile specimen with high temperature adhesive, and connected to the adapter in the main loading system through the outer shoulder in the pipe bonding sleeve. Step S3: Heat the axially tensile specimen using a heating system, and monitor and control the temperature of the axially tensile specimen using a temperature measurement and control system. Step S4: The main loading system performs axial strength testing on the axially tensile specimen and records and analyzes the test data.

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