A Thermal Fatigue Experiment Device and Method for Metal Materials

Abstract

The present invention relates to a thermal fatigue experiment device and method for metal materials. The thermal fatigue experiment device for metal materials includes an experimental platform, a measurement system, a data acquisition system, and a control system. The experimental platform includes a heating device and a cooling device. The heating device uses a transformer to output a large current to heat the specimen, and adjusts the heating power through a thyristor voltage regulation module. The cooling device uses an air knife to cool the specimen by air cooling. The measurement system includes a thermocouple group, a force sensor, and an industrial camera, which are respectively used to measure the temperature distribution, force load, and deformation of the specimen. The control system includes an industrial computer and the upper computer program installed thereon. Under the control of the control system, the temperature curve of the specimen during the thermal cycle can be various waveforms such as trapezoidal, triangular, and sine-cosine. The present invention has high heating and cooling efficiency, and can obtain the deformation parameters of the specimen during the thermal cycle through optical measurement methods, providing a new low-cost solution for the thermal fatigue experiment of metal materials.

Description

Technical Field

[0001] The present invention relates to the field of material experimental instruments, and particularly relates to a thermal fatigue experimental device and method for metal materials. Background Art

[0002] For metal materials working in high-temperature scenarios, after being used for a certain period of time, defects will occur in the materials. The main reason is that the cyclic thermal stress damages the materials, and this phenomenon is called the thermal fatigue of metals. The thermal fatigue performance of metals is usually the key factor determining the service life of metal components in high-temperature systems. Therefore, before being put into use, metal materials applied to high-temperature systems must undergo thermal fatigue experiments.

[0003] In order to provide an effective solution for the thermal fatigue experiments of metal materials, many research institutions at home and abroad have conducted relevant research and achieved some results. The MTS company in the United States developed a set of thermo-mechanical coupled fatigue test devices based on its material testing machine. This device heats the experimental specimen by induction heating and cools the specimen by air cooling, and can effectively test the thermal fatigue performance of materials. However, due to the limitations of induction heating, when the experimental specimen is not a regular cylindrical shape but a square or other irregular shape, the temperature distribution of the specimen will become very uneven, which does not meet the requirements of thermal fatigue experiments. In addition, since this experimental device is built on an MTS material testing machine, its usage scenario is limited and the cost is high.

[0004] Xie Jijia et al. in China developed a thermo-mechanical fatigue experimental device based on laser heating. During the experiment, the specimen is fixed on the horizontal rotating shaft of the device, and 360° heating of the specimen and mechanical load changes are achieved by rotating the rotating shaft; however, the uniformity of this heating method depends to a large extent on the rotation speed of the rotating shaft. When the rotation speed is low, the heating of the specimen will become significantly uneven. In addition, this device does not adopt cooling measures and the cooling speed is slow.

[0005] Xia Pengcheng et al. developed a thermal fatigue testing machine for superalloys. The heating system of this testing machine is an electric resistance furnace, and the cooling system is a water tank. The testing machine drives the specimen to enter the heating system and the cooling system respectively through a lifting system to achieve heating and cooling of the specimen. This heating method by electric resistance furnace has a slightly low heating speed and it is difficult to achieve rapid heating. Moreover, the overall structure of this testing machine is complex and the conversion efficiency of heating and cooling is low.

[0006] References

[0007] [1] Xie Jijia, Zhao Aiguo, Wu Xiaodong, Hong Youshi. A device and method for thermo-mechanical fatigue experiments [P]. Beijing: CN101876611B, 2012-05-30.

[0008] [2] Xia Pengcheng, Han Guanpeng, Xie Kun, Yu Jinjiang, Sun Xiaofeng, Guan Hengrong, Hu Zhuangqi. Development and experimental research of a hot fatigue testing machine for superalloys [J]. Materials Review, 2013, 27(12): 20 - 22 + 35. SUMMARY OF THE INVENTION

[0009] The object of the present invention is to address the deficiencies of the prior art and propose a thermal fatigue experimental device and method for metal materials. By using the method of large - current heating and high - pressure gas cooling, the following functions and indicators are achieved:

[0010] (1) Automation; the device automatically completes the thermal cycle of "heating - heat preservation - cooling";

[0011] (2) Faster heating and cooling speeds; within 1000 °C, the average heating speed can reach 30 °C / s, and the average cooling speed can reach 15 °C / s;

[0012] (3) Higher temperature control accuracy; the temperature control accuracy in the heat preservation section is within ±1%;

[0013] (4) Ensure uniform heating of the specimen;

[0014] (5) Make the device structure simple, easy to install, and low - cost.

[0015] To achieve the above object, the present invention adopts the following technical means:

[0016] A thermal fatigue experimental device for metal materials, comprising an experimental platform, a measurement system, a data acquisition system (14), and a control system;

[0017] The experimental platform includes a rectangular frame (1), an upper fixture (201), a lower fixture (202), a thyristor voltage - regulating module (3), a transformer (4), an air knife (5), an electromagnetic valve (6), an air compressor (7), a servo pressure - regulating valve (8), a first relay (16a), and a second relay (16b);

[0018] The measurement system includes a thermocouple group (10), a filtering module (11), a force sensor (12), a light source (9), and an industrial camera (13);

[0019] The upper fixture (201) is installed on the upper side of the rectangular frame (1), and the lower fixture (202) is installed on the lower side of the rectangular frame (1); the output ends of the transformer (4) are respectively connected to the upper fixture (201) and the lower fixture (202), and the output end of the thyristor voltage regulating module (3) is connected to the input end of the transformer (4) through a wire; the air knife (5) is installed on the rectangular frame (1); the solenoid valve (6) is connected between the air compressor (7) and the air knife (5) through an air pipe; the servo pressure regulating valve (8) is installed in the air path between the air compressor (7) and the solenoid valve (6) through an air pipe; the first relay (16a) is connected in the power supply circuit of the solenoid valve (6); the second relay (16b) is connected in the power supply circuit of the thyristor voltage regulating module (3); the filtering module (11) is connected between the thermocouple group (10) and the data acquisition system (14); the force sensor (12) is installed between the lower fixture (202) and the rectangular frame (1); the industrial camera (13) is installed directly in front of the specimen (17) on the rectangular frame (1); the data acquisition system (14) is connected to the control system.

[0020] Specifically, the present invention provides a metal thermal fatigue experimental device, including an experimental platform, a measurement system, a data acquisition system and a control system.

[0021] The experimental platform includes a rectangular frame, upper and lower fixtures, relays, a heating device and a cooling device.

[0022] The upper cross beam of the rectangular frame is connected to the two side support beams by bolts, and the height of the cross beam can be adjusted by tightening or loosening the bolts to adapt to specimens of different lengths.

[0023] The upper and lower fixtures are installed on the upper and lower sides of the rectangular frame by bolts and are used to fix the specimen in the vertical direction. The upper and lower fixtures can be freely replaced, and different-shaped specimens can be fixed by replacing different fixtures.

[0024] The heating device includes a transformer and a thyristor voltage regulating module; the transformer is a low-voltage high-current transformer, and the output end of the transformer is connected to the upper and lower fixtures. When the transformer outputs a certain voltage, a large current will flow through the specimen, causing the specimen to be quickly heated; the output end of the thyristor voltage regulating module is connected to the input end of the transformer. By inputting a variable analog signal to the control end of the thyristor voltage regulating module, the output voltage of the transformer can be changed within a corresponding range, thereby realizing the adjustment of the heating power.

[0025] The cooling device includes an air compressor, a solenoid valve, an air knife, and a servo pressure regulating valve. The air knife is mounted on a rectangular frame with its blade facing the specimen. The solenoid valve is connected between the air compressor and the air knife. When the solenoid valve is opened, the air knife blows the high-pressure gas in the air compressor towards the specimen, causing the specimen to cool rapidly. The servo pressure regulating valve is installed in the gas circuit between the air compressor and the solenoid valve to stabilize the air pressure in the gas circuit and achieve precise control of the cooling rate.

[0026] The relay is a two-way relay, which is respectively connected to the power supply circuits of the solenoid valve and the thyristor voltage regulating module, and is used to realize the on-off control of heating and cooling.

[0027] The measurement system includes a thermocouple group, a filtering module, a force sensor, a light source, and an industrial camera.

[0028] The thermocouple group includes multiple thermocouples. The multiple thermocouples are connected to different positions on the surface of the specimen by welding, and can measure the temperature and temperature distribution of the specimen. The filtering module is used to filter out the noise in the output signal of the thermocouple and improve the quality of the output signal of the thermocouple.

[0029] The force sensor is installed between the lower fixture and the rectangular frame to measure the force load of the specimen in the vertical direction.

[0030] The light source is a blue light source, which is installed at the same height as the specimen to illuminate the specimen and provide sufficient brightness for the optical measurement of the specimen. The industrial camera is mounted directly in front of the specimen on the rectangular frame. Using the industrial camera, parameters such as the deformation and strain of the specimen can be quickly calculated by optical measurement methods. A filter is installed on the lens of the industrial camera, which can filter out all light except blue light, avoiding the influence of natural light and the red light emitted by the specimen at high temperatures on optical measurement.

[0031] The data acquisition system includes a set of multi-functional data acquisition cards. The data acquisition system is used to acquire the temperature signals of multiple thermocouples in the thermocouple group, the force signals of the force sensor, the air pressure signals of the servo pressure regulating valve, and the image signals of the industrial camera. At the same time, the data acquisition system can output multiple digital signals and analog signals under the control of the control system.

[0032] The control system includes an industrial computer and the upper computer program installed on it. The control system can control the temperature curve in the thermal cycle process into various waveforms such as trapezoid, triangle, and sine-cosine according to the requirements of different experiments.

[0033] The present invention also provides a method for thermal fatigue experiment of metal materials, using the device described in any one of the above, including the following steps: Install the specimen to be tested (17). First, select one thermocouple from the thermocouple group (10) and weld it at the temperature control part of the specimen (17). This thermocouple (10) serves as the main control thermocouple for controlling the temperature of the specimen (17). At the same time, weld the other thermocouples in the thermocouple group (10) except the main control thermocouple on the specimen (17) for measuring the temperature distribution of the specimen (17). Subsequently, fix the specimen (17) vertically in the rectangular frame (1) through the upper fixture (201) and the lower fixture (202).

[0034] Set the low temperature value, high temperature value, heating time, heat preservation time, and cooling time of the thermal cycle. Subsequently, start the thermal cycle. In the heating stage, the specimen (17) is heated at a uniform speed and then heat-preserved. When the heat preservation ends, stop heating, and the specimen (17) is cooled by the high-pressure gas blown by the air knife (5).

[0035] Among them, at the same time when the thermal cycle starts, the industrial camera (13) continuously takes pictures of the specimen (17), and the deformation data of the specimen (17) during the thermal cycle can be calculated by processing the collected pictures.

[0036] The present invention has the following advantages and positive effects:

[0037] (1) Fast heating and cooling speeds, and uniform heating effect. The present invention uses the method of direct power supply for heating, with high heating efficiency, which can reach 30 °C / s. Moreover, since both the current and the resistance of the specimen are uniform, according to Joule's law, the heating speed of each part of the specimen is uniform. Cooling is carried out by using high-pressure air flow, with a fast cooling speed. In addition, due to the pressure regulation function of the servo pressure regulating valve, precise control of the cooling rate can be achieved.

[0038] (2) Convenient image acquisition. The overall structure of the present invention is an open vertical structure, which is conducive to the installation of optical equipment, and the adopted heating method will not affect the image acquisition of the specimen, creating favorable conditions for the application of optical measurement methods to thermal fatigue experiments.

[0039] (3) The optical measurement method is adopted. The present invention applies the optical measurement method to thermal fatigue experiments, which is conducive to studying the changes in the shape characteristics of specimens in thermal fatigue experiments.

[0040] (4) Simple structure and low cost. The proposed thermal fatigue experiment device for metal materials has no complex mechanical structure, is easy to install, and has a low cost. Description of the Drawings

[0041] Figure 1 General structural schematic diagram of the present invention

[0042] Figure 2 Schematic diagram of specimen installation;

[0043] Figure 3 A temperature control curve of the present invention.

[0044] In the figure: 1 - rectangular frame, 201 - upper fixture, 202 - lower fixture, 3 - thyristor voltage regulating module, 4 - transformer, 5 - air knife, 6 - solenoid valve, 7 - air compressor, 8 - servo pressure regulating valve, 9 - light source, 10 - thermocouple group, 11 - filtering module, 12 - force sensor, 13 - industrial camera, 14 - data acquisition system, 15 - industrial control computer, 16a - first relay, 16b - second relay, 17 - specimen. Specific implementation manner

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] A metal thermal fatigue experiment device related to the present invention includes an experimental platform, a measurement system, a data acquisition system, and a control system.

[0047] As Figure 1 shown, the experimental platform includes a rectangular frame 1, an upper fixture 201, a lower fixture 202, a first relay 16a and a second relay 16b, a heating device, and a cooling device.

[0048] As Figure 1-2 described, the crossbeam above the rectangular frame 1 is connected to the side support beam by bolts. Before installing the specimen, the height of the crossbeam above can be adjusted by loosening or tightening the bolts so that the experimental platform can adapt to the length of the specimen. The upper fixture 201 is installed on the upper side of the rectangular frame 1 by bolts. The lower fixture 202 is installed on the lower side of the rectangular frame 1 by bolts. When installing the specimen, the upper fixture 201 and the lower fixture 202 are used to clamp the clamping end of the specimen 17, so that the specimen 17 is fixed in the rectangular frame 1, thereby restricting the longitudinal expansion and contraction of the specimen 17 during the thermal cycle; for specimens of different shapes, the upper fixture 201 and the lower fixture 202 can be freely replaced to make the upper fixture and the lower fixture suitable for the specimen.

[0049] The heating device includes a transformer 4 and a thyristor voltage regulating module 3; the transformer 4 includes an input end and an output end, and the output end of the transformer 4 is respectively connected to the upper fixture 201 and the lower fixture 202 through thick copper cables. During the heating stage of the thermal cycle, the transformer 4 outputs a voltage, and an electric current loop is formed through the specimen 17. Since the resistivity of the specimen 17 is much greater than that of the thick copper cable, the upper fixture 201 and the lower fixture 202, almost all of the output voltage of the transformer 4 is distributed across both ends of the specimen 17, and the specimen 17 is rapidly heated. Within 1000 °C, the average heating rate can reach 30 °C / S; in addition, the current at each point of the specimen 17 is equal, and its resistance is also uniform, which ensures the uniformity of specimen heating; the thyristor voltage regulating module 3 includes an input end, an output end and a control end. The input end of the thyristor voltage regulating module 3 is connected to 220V alternating current, and the output end is connected to the input end of the transformer 4 through a wire. By inputting a controllable analog signal at the control end of the thyristor voltage regulating module 3, the output voltage of the transformer 4 can be adjusted, thereby adjusting the heating power. The control end of the thyristor voltage regulating module 3 is connected to the data acquisition system 14.

[0050] The first relay 16a is connected in the power supply circuit of the solenoid valve 6. The second relay 16b is connected in the power supply circuit of the thyristor voltage regulating module 3. The data acquisition system 14 is connected to the second relay 16b. The data acquisition system 14 is sequentially connected to the first relay 16a and the solenoid valve 6.

[0051] The cooling device includes an air compressor 7, a solenoid valve 6, an air knife 5 and a servo pressure regulating valve 8; the air compressor 7 is used for compressing and storing the high-pressure gas required for cooling; the air knife 5 includes an air inlet and a blade. As Figure 2 shown, the air knife 5 is installed on the rectangular frame 1 with the blade facing the specimen 17, and the air inlet of the air knife 5 is connected to the air compressor 7 through the solenoid valve 6.

[0052] The servo pressure regulating valve 8 is installed in the gas circuit between the air compressor 7 and the solenoid valve 6 through a gas pipe. The servo pressure regulating valve 8 is connected to the data acquisition system 14. The solenoid valve 6 is sequentially connected to the servo pressure regulating valve 8 and the air compressor 7.

[0053] During the cooling stage of the thermal cycle, the solenoid valve 6 opens. The air knife 5 not only blows high-pressure gas from the blade edge, but the blown high-pressure gas can also create a negative pressure in the space near the blade edge of the air knife 5, thereby driving a part of the surrounding air to blow towards the specimen 17, enabling the specimen 17 to cool rapidly. Within 1000 °C, the average cooling rate can reach 15 °C / S. The servo pressure regulating valve 8 can monitor the air pressure in the air circuit. The air pressure signal is collected by the data acquisition system 14 and then input into the control system. During the experiment, the working time of the servo pressure regulating valve 8 is the time period from the end of one cooling to the start of the next cooling. The control system controls the data acquisition system 14 to output an analog signal according to the air pressure state in the air circuit at this time, enabling the servo pressure regulating valve 8 to regulate the air pressure in an exhaust manner, so that the air tank pressure of the air compressor 7 always remains at a constant value before the start of cooling, which is conducive to the precise control of the cooling rate.

[0054] The measurement system includes a thermocouple group 10, a filtering module 11, a force sensor 12, a light source 9, and an industrial camera 13.

[0055] The thermocouple group 10 includes multiple thermocouples. The temperature measurement end of each thermocouple is connected to the surface of the specimen 17 by welding. The filtering module 11 includes a signal input end and a signal output end. All the thermocouples in the thermocouple group 10 are connected to the signal input end of the filtering module 11. The filtering module 11 can filter out the noise in the thermocouple signal and output a high-quality signal. The signal output end of the filtering module 11 is connected to the data acquisition system 14. The data acquisition system 14 is connected to the industrial computer 15 of the control system. During the experiment, multiple thermocouples can be used to measure the temperatures at different positions on the specimen 17 to obtain the temperature distribution of the specimen 17. One of the thermocouples is selected as the main control thermocouple. After the data acquisition system 14 collects the temperature of the main control thermocouple, it is fed back and input into the control system. The control system controls the data acquisition system 14 to output a controllable analog signal to the control end of the thyristor voltage regulating module 3 to adjust the output voltage of the transformer 4, thereby adjusting the heating power of the specimen 17 and achieving precise control of the temperature. In specific implementation, the temperature control accuracy during the heat preservation process can be controlled within ±1%.

[0056] The force sensor 12 is installed between the lower fixture 202 and the rectangular frame 1.

[0057] The data acquisition system includes a set of multifunctional data acquisition cards. The industrial camera 13 is connected to the data acquisition system 14.

[0058] When conducting optical measurements, the light source 9 is installed at the same height as the specimen 17 to illuminate the specimen and provide sufficient brightness for the specimen. The industrial camera 13 is installed directly in front of the specimen 17 and the rectangular frame 1, facing the specimen 17. According to the preset frequency, the industrial camera 13 continuously takes pictures of the specimen 17. At the same time, the image data obtained by the industrial camera 13 is collected by the data acquisition system 14 and then input into the control system. The control system quickly calculates parameters such as the deformation and strain of the specimen 17.

[0059] The control system is the industrial personal computer 15 and the upper computer program carried by it. On the one hand, the control system is used to process the data collected by the data acquisition system 14, and on the other hand, it controls the data acquisition system 14 to output multiple control signals to control the whole device: output two analog signals to control the thyristor voltage regulation module 3 and the servo pressure regulating valve 8, and output two digital signals to control the first relay 16a and the second relay 16b. The first relay 16a and the second relay 16b are respectively connected in the power supply circuits of the solenoid valve 6 and the thyristor voltage regulation module 3. The control system controls the opening and closing of the two relays by controlling the data acquisition system 14 to output digital signals, so as to realize the on-off control of heating and cooling. In addition, through the overall control of the device, the control system can make the temperature curve of the specimen 17 in the thermal cycle be various waveforms such as trapezoidal, triangular, sine-cosine, etc.

[0060] Example 1

[0061] For the existing specimen 17 to be tested, first select one thermocouple from the thermocouple group 10 and weld it at the temperature control point of the specimen 17. This thermocouple 10 is used as the main control thermocouple to control the temperature of the specimen 17. At the same time, the other thermocouples in the thermocouple group 10 are welded at other temperature measurement points of the specimen 17 to measure the temperature distribution of the specimen 17. Subsequently, the specimen 17 is vertically fixed in the rectangular frame 1 through the upper fixture 201 and the lower fixture 202.

[0062] Set the low temperature value of the thermal cycle to 100 °C, the high temperature value to 900 °C, and at the same time set the heating time to 60 s, the heat preservation time to 180 s, and the cooling time to 60 s. Subsequently, start the thermal cycle. In the heating stage, the specimen 17 is heated at a uniform speed. When the temperature of the specimen reaches 900 °C, heat preservation begins. In the heat preservation stage, the temperature of the specimen 17 is controlled at 900 °C. When the heat preservation ends, heating stops, and the specimen 17 is quickly cooled by the high-pressure gas blown by the air knife 5. When the temperature of the specimen reaches 100 °C, cooling stops. Thus, one thermal cycle period ends. At the same time, the next thermal cycle period begins. Figure 3 This is the temperature curve of one thermal cycle period of this example. In the curve, the actual temperature in the heating and heat preservation stages can be highly coincident with the target temperature curve, and the overall cooling rate can also be ensured in the cooling stage.

[0063] At the same time as the thermal cycle starts, the industrial camera 13 begins to continuously photograph the specimen 17 at the set frequency. By processing the collected pictures, the deformation data of the specimen 17 during the thermal cycle can be calculated.

[0064] The parts not elaborated in detail in the present invention belong to the well-known technologies of those skilled in the art. The above-described embodiments merely describe the preferred embodiments of the present invention. The preferred embodiments do not elaborate on all the details, nor do they limit the invention to the specific embodiments described. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A thermal fatigue experimental device for metal materials, characterized in that: It includes an experimental platform, a measurement system, a data acquisition system (14) and a control system; The experimental platform includes a rectangular frame (1), an upper fixture (201), a lower fixture (202), a thyristor voltage regulating module (3), a transformer (4), an air knife (5), a solenoid valve (6), an air compressor (7), a servo pressure regulating valve (8), a first relay (16a) and a second relay (16b); The measurement system includes a thermocouple group (10), a filtering module (11), a force sensor (12), a light source (9) and an industrial camera (13); The upper fixture (201) is installed on the upper side of the rectangular frame (1), and the lower fixture (202) is installed on the lower side of the rectangular frame (1); the output terminals of the transformer (4) are respectively connected to the upper fixture (201) and the lower fixture (202), and the output terminal of the thyristor voltage regulating module (3) is connected to the input terminal of the transformer (4) through a wire; the air knife (5) is installed on the rectangular frame (1); the solenoid valve (6) is connected between the air compressor (7) and the air knife (5) through an air pipe; the servo pressure regulating valve (8) is installed in the air path between the air compressor (7) and the solenoid valve (6) through an air pipe; the first relay (16a) is connected in the power supply circuit of the solenoid valve (6); the second relay (16b) is connected in the power supply circuit of the thyristor voltage regulating module (3); the filtering module (11) is connected between the thermocouple group (10) and the data acquisition system (14); the force sensor (12) is installed between the lower fixture (202) and the rectangular frame (1); the industrial camera (13) is installed directly in front of the specimen (17) on the rectangular frame (1); the data acquisition system (14) is connected to the control system.

2. The device according to claim 1, characterized in that: The upper crossbeam of the rectangular frame (1) is connected to the two side support beams by bolts, and the height of the upper crossbeam can be adjusted by tightening or loosening the bolts to adapt to specimens of different lengths.

3. The device according to claim 1, characterized in that: The air knife (5) is installed on the rectangular frame (1) with the blade facing the specimen (17).

4. The device according to claim 1, characterized in that: The measurement system further includes a light source (9); the light source (9) is used to illuminate the specimen (17).

5. The device according to claim 1, characterized in that: The data acquisition system (14) includes a multi-functional data acquisition card.

6. The device according to claim 1, characterized in that: The control system includes an industrial personal computer (15).

7. The device according to claim 1, characterized in that: The data acquisition system (14) is connected to the first relay (16a) and the second relay (16b).

8. The device according to claim 1, characterized in that: The air knife (5) includes an air inlet and a blade, and the air inlet of the air knife (5) is connected to the air compressor (7) through the solenoid valve (6).

9. The device according to claim 1, characterized in that: The servo pressure regulating valve (8) is connected to the data acquisition system (14).

10. A method for thermal fatigue experiment of a metal material, characterized in that: Using the device according to any one of claims 1-9, comprising the following steps: installing the specimen to be tested (17), first selecting one thermocouple from the thermocouple group (10), welding it at the temperature control position of the specimen (17), and this thermocouple serves as the main control thermocouple for controlling the temperature of the specimen (17); at the same time, welding the other thermocouples in the thermocouple group (10) except the main control thermocouple on the specimen (17) for measuring the temperature distribution of the specimen (17), and then vertically fixing the specimen (17) in the rectangular frame (1) through the upper fixture (201) and the lower fixture (202); Setting the low temperature value, high temperature value, heating time, heat preservation time and cooling time of the thermal cycle; then starting the thermal cycle. In the heating stage, the specimen (17) is heated at a uniform speed and then heat-preserved; when the heat preservation ends, the heating is stopped, and the specimen (17) is cooled by the high-pressure gas blown by the air knife (5); Wherein, simultaneously with the start of the thermal cycle, the industrial camera (13) continuously takes pictures of the specimen (17), and the deformation data of the specimen (17) during the thermal cycle can be calculated by processing the collected pictures.

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