Single-shaft high-temperature ultrahigh-cycle fatigue test device with automatic temperature control function

Abstract

The invention provides an automatic temperature control single-shaft high-temperature ultrahigh-cycle fatigue test device, which comprises a single-shaft ultrahigh-cycle fatigue test system, an induction heating system, an automatic water level control system and a central control system, the single-shaft ultra-high-cycle fatigue test system comprises a stand column, an ultrasonic transducer fixing disc, a base, an ultrasonic generator, an ultrasonic transducer, a displacement amplifier, an extension bar and a test piece. The induction heating system comprises an electromagnetic induction heater, a magnetic induction heating coil and an infrared thermometer, the automatic water level control system comprises a water tank, a water stop valve and a water suction pump, and the central control system comprises a fatigue control system, an automatic temperature control system and a linkage system. According to the invention, the uniaxial ultrahigh-cycle fatigue test of the material and the accurate control of the temperature loading of the sample can be realized, the heating can be automatically stopped after the sample is broken so as to prevent oxidation, and the uniaxial ultrahigh-cycle fatigue test with the frequency of 20KHz in a high-temperature environment is effectively realized.

Description

Technical Field

[0001] The invention belongs to the technical field of fatigue testing devices, and in particular relates to a uniaxial high-temperature and ultra-high-cycle fatigue testing device with automatic temperature control. Background Art

[0002] Ultra-high cycle fatigue refers to the phenomenon that a material is subjected to cyclic stress far below the yield strength for 10 7 The phenomenon of fatigue failure occurs after more than 10 cycles. The traditional view is that when the load of a component is lower than a certain value, it is considered to have an infinite life. However, the results of ultrasonic fatigue tests show that after working for 10 7 When the number of cycles exceeds 100, fatigue fracture still occurs when the working load of the parts is lower than the fatigue limit, and there is no fatigue limit. Although the stress amplitude of this vibration load is small, its frequency is very high, reaching more than several thousand hertz. High-frequency damage seriously threatens the working safety and reliability of parts.

[0003] However, in some fields, key components and structures are often subjected to the combined effects of high temperature and stress during service. Especially in the aerospace field, key components such as aero-engine blades, blisks, gears, etc. will be subjected to high-frequency, low-amplitude vibration loads in a high-temperature environment during service, and the number of cyclic loads is usually 10 7 Therefore, high-speed running parts such as aircraft engine blades, blisks, gears, etc. pay special attention to ultra-high cycle fatigue performance under high temperature conditions.

[0004] The Chinese invention patent with the announcement number CN107144474A discloses a high-temperature ultra-high cycle fatigue test system, which includes a mechanical test device, a workbench, and a heating device. The lower edge of the workbench is fixed to the frame of the electromagnetic vibration table by bolts, and there is a through hole in the center of the crossbeam at the upper end of the workbench; the worm gear device passes downward from the through hole; the upper end of the force sensor is connected to the lower end of the worm, and the lower end is connected to the upper end of the upper fixture, the lower end of the upper fixture is connected to the upper threaded section of the sample, the lower threaded section of the sample is connected to the upper end of the lower fixture, and the lower end of the lower fixture is connected to the output shaft of the electromagnetic vibration table; the counterweight is sleeved on the output shaft of the electromagnetic vibration table and fixed on the vibration table of the electromagnetic vibration table; the sample is located in the furnace cavity of the high-temperature furnace.

[0005] However, the test frequency of the device is 100Hz. When the test cycle reaches 10 8 It takes about 27 days, and when the specimen reaches the fatigue limit and is damaged, the heating equipment cannot be linked and the heating cannot be turned off in time, which will cause high oxidation near the fracture and affect fatigue analysis.

[0006] The Chinese invention patent with the announcement number CN116413150A discloses a multi-axis ultra-high frequency and multi-axis low frequency composite variable amplitude thermomechanical fatigue test device, which includes a multi-axis low frequency load loading system, an adaptive clamping system, a central control system, etc. Two columns are installed on the base, the two ends of the beam are fixed on the columns, the hydraulic rod is fixed on the base, the upper hydraulic chuck is installed in the middle of the beam, the lower hydraulic chuck is installed in the middle of the base, and the force sensor is installed between the lower hydraulic chuck and the base; the multi-axis ultra-high frequency load loading system can be installed in the multi-axis low frequency load loading system through the adaptive clamping system, and the upper end of the multi-axis ultra-high frequency load loading system can be installed in the positioning grooves of the upper and lower pressure plates through the positioning ear plate of the upper amplitude modulator. Similarly, the lower end of the multi-axis ultra-high frequency load loading system can be installed in the positioning grooves of the upper and lower pressure plates through the positioning ear plate of the lower amplitude modulator.

[0007] However, this device is not suitable for ultra-high cycle and high temperature fatigue tests under uniaxial load. At the same time, the high temperature water circulation device in the system cannot automatically control the water level, which poses a safety hazard. The heating equipment cannot be automatically shut down after the specimen is fatigued, which leads to fracture oxidation.

[0008] Based on this, a uniaxial high-temperature ultra-high cycle fatigue test device with automatic temperature control is proposed, which can systematically study the ultra-high cycle fatigue damage of materials under high temperature environment. It controls the ultra-high cycle fatigue test device and heating equipment through a computer to realize automatic temperature control, and has carried out ultra-high cycle fatigue tests under high temperature and constant temperature conditions. Compared with traditional high-temperature test devices, it can not only realize high-precision temperature control at a certain high temperature, but also carry out ultra-high cycle fatigue tests based on 20KHz vibration frequency, which improves the ultra-high cycle fatigue test process under high temperature environment and provides strong support for subsequent research in this field. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a uniaxial high-temperature ultra-high cycle fatigue testing device with automatic temperature control in view of the deficiencies of the above-mentioned prior art, so as to solve the problems raised in the above-mentioned background technology.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: In the first aspect, an automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue test device includes a uniaxial ultra-high cycle fatigue test system, an induction heating system, an automatic water level control system and a central control system; The uniaxial ultra-high cycle fatigue test system comprises a column, an ultrasonic transducer fixing plate, a base, an ultrasonic generator, an ultrasonic transducer, a displacement amplifier, an extension rod and a test piece; three columns are provided, and the three columns, the base and the ultrasonic transducer fixing plate form a bracket, the ultrasonic transducer is placed on the upper end of the ultrasonic transducer fixing plate, the ultrasonic generator is connected to the ultrasonic transducer by wire, and the ultrasonic transducer is connected to the displacement amplifier, the extension rod and the test piece in sequence by bolts; The induction heating system comprises an electromagnetic induction heater, a magnetic induction heating coil and an infrared thermometer, wherein the electromagnetic induction heater is connected to the magnetic induction heating coil, the heating section of the magnetic induction heating coil is installed on the periphery of the test piece, and the infrared thermometer is used to monitor the temperature of the test piece; The automatic water level control system comprises a water tank, a water stop valve and a water pump, wherein the water stop valve is connected to a faucet installed on the water tank through a water pipe, and the water pump completes the communication between the water tank and the electromagnetic induction heater; The central control system includes a fatigue control system, an automatic temperature control system and a linkage system. The fatigue control system is connected to the ultrasonic generator signal, the automatic temperature control system is connected to the electromagnetic induction heater signal, and the linkage system connects the fatigue control system and the automatic temperature control signal through an acquisition card.

[0011] As a further illustration of the present invention, the ultrasonic transducer fixing plate is a circular ring structure, and the outer diameter of the ultrasonic transducer fixing plate is the same as the outer diameter of the base.

[0012] As a further illustration of the present invention, the ultrasonic transducer is clamped in an ultrasonic transducer fixing plate.

[0013] As a further explanation of the present invention, the ultrasonic transducer fixing plate is provided with bolt holes cooperating with the columns, and the ultrasonic transducer fixing plate is also provided with positioning grooves cooperating with the positioning stop ears on the outer side of the ultrasonic transducer.

[0014] In a second aspect, a sample method of a uniaxial high temperature ultra-high cycle fatigue test device with automatic temperature control comprises the following steps: The uniaxial ultra-high cycle fatigue test system is fixed on the bracket through the ultrasonic transducer fixing plate, and the test piece is connected to the extension rod through bolts; the ultrasonic generator receives the signal of the fatigue control system in the central control system through wired connection, and then inputs it into the ultrasonic transducer, and the ultrasonic transducer converts the received ultrasonic signal into mechanical displacement, which is amplified by the displacement amplifier and then transmitted to the test piece through the extension rod, so that the test piece is subjected to uniaxial fatigue test; The induction heating system changes the magnetic field by applying current to the magnetic induction heating coil, and the magnetic field then causes the test piece to generate heat due to eddy current effect and hysteresis effect; the magnetic induction heating coil is aligned with the center of the test piece, and the infrared thermometer is aligned with the middle position of the test piece; The water of the automatic water level control system flows from the faucet into the water tank through the water stop valve, and the water in the water tank enters the electromagnetic induction heater through the water pump. When the water in the water tank is higher than the water level line, the water stop valve is closed, and the water pump is still in working state, which will cause the water level to drop. When the water level drops below the water level line, the water stop valve is opened again, and the operation is repeated; The fatigue control system in the central control system can start the uniaxial ultra-high cycle fatigue test system by controlling the ultrasonic generator. The experimental stress is set in the fatigue control system. When the test piece breaks, causing the feedback frequency to exceed the range of 20±0.5KHz, the ultrasonic generator is automatically turned off and the signal is transmitted to the fatigue control system in the central control system; the automatic temperature control system in the central control system controls the on / off of the induction heating system through a relay, and the temperature output by the infrared thermometer in the induction heating system is converted into a voltage through an acquisition card. The voltage value corresponds to the temperature value one by one, and the voltage is then transmitted to the relay through the automatic temperature control system; When the heating temperature is higher than the set temperature, the voltage entering the automatic temperature control system is higher than the voltage corresponding to the set temperature. At this time, the automatic temperature control will close the relay to turn off the induction heating system. When the temperature drops below the set temperature, the automatic temperature control system will open the relay to turn on the induction heating system. The linkage system in the central control system, the fatigue control system in the central control system transmits the received test piece fracture signal to the acquisition card by changing the voltage. After the working voltage collected by the acquisition card is changed, the signal is transmitted to the automatic temperature control system. The automatic temperature control system detects the voltage change and automatically cuts off the transmission of the electrical signal through the relay, thereby shutting down the induction heating system, and finally achieving the effect of stopping heating when the test piece breaks to prevent oxidation of the fracture.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The ultra-high cycle fatigue test device of ultrasonic frequency in the present invention converts the 20±0.5kHz electric energy provided by the ultrasonic generator into mechanical motion of the same frequency, and then amplifies the vibration displacement output by the transducer through the displacement amplifier to excite the fatigue specimen to resonate and realize fatigue loading. In some specific fields, it is necessary to study the ultra-high cycle fatigue performance of materials under high temperature environment. It can not only realize the uniaxial ultra-high cycle fatigue test of materials and the precise control of the temperature loading of the specimen, but also realize the automatic termination of heating after the specimen breaks to prevent oxidation. At the same time, in order to prevent the test safety problems that may be caused by water circulation during the heating process, an automatic water level control system is also installed, thereby effectively realizing the 20KHz frequency uniaxial ultra-high cycle fatigue test in high temperature environment.

[0016] 2. The present invention can realize uniaxial ultra-high cycle fatigue test in a high temperature environment, and solves the defect that the magnetic induction heating coil cannot accurately control the loading temperature; it realizes the linkage of the fatigue control system with the automatic temperature control system, so that when the sample is fatigue fractured, the ultra-high cycle fatigue test system is stopped and the heating device is stopped in conjunction, avoiding the sample being in a heating environment after fracture, which leads to oxidation of the fracture and affects subsequent analysis; it solves the problem that the flow rate cannot be accurately controlled after the water pumping section of the traditional magnetic induction heating coil is placed in the container, and avoids the damage of the heating device caused by the low water level in the container or the hidden danger of flooding caused by the high water level. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an overall schematic diagram of the present invention; Figure 2 This is a schematic diagram of the central control system of the present invention; Figure 3 This is a schematic diagram of a uniaxial ultra-high cycle fatigue test device of the present invention; Figure 4 It is a schematic diagram of the ultrasonic transducer fixing plate of the present invention.

[0018] Description of reference numerals: 10-Uniaxial ultra-high cycle fatigue test system; 20-Induction heating system; 30-Automatic water level control system; 40-Central control system; 101-Column; 102-Ultrasonic transducer fixing plate; 103-Base; 104-Ultrasonic generator; 105-Ultrasonic transducer; 106-Displacement amplifier; 107-Extension rod; 108-Test piece; 109-Bolt hole; 110-Location groove; 111-Location stop ear; 201-Electromagnetic induction heater; 202-Magnetic induction heating coil; 203-Infrared thermometer; 301-Water tank; 302-Water stop valve; 303-Water pump; 401-Fatigue control system; 402-Automatic temperature control system; 403-Linkage system. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1-4 As shown, the present invention provides a technical solution: an automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue test device, comprising a uniaxial ultra-high cycle fatigue test system 10, an induction heating system 20, an automatic water level control system 30 and a central control system 40; The uniaxial ultra-high cycle fatigue test system 10 includes a column 101, an ultrasonic transducer fixing plate 102, a base 103, an ultrasonic generator 104, an ultrasonic transducer 105, a displacement amplifier 106, an extension rod 107 and a test piece 108; three columns are provided, and the three columns 101, the base 103 and the ultrasonic transducer fixing plate 102 form a bracket; The ultrasonic transducer fixing plate 102 is a circular ring structure, and the outer diameter of the ultrasonic transducer fixing plate 102 is the same as the outer diameter of the base 103 .

[0021] The ultrasonic transducer 105 is clamped in the ultrasonic transducer fixing plate 102, the ultrasonic transducer 105 is placed on the upper end of the ultrasonic transducer fixing plate 102, the ultrasonic generator 104 is connected to the ultrasonic transducer 105 by wire, and the ultrasonic transducer 105 is connected to the displacement amplifier 106, the extension rod 107, and the test piece 108 in sequence by bolts; In order to facilitate connection, the ultrasonic transducer fixing plate 102 is provided with a bolt hole 109 that cooperates with the column 101 , and the ultrasonic transducer fixing plate 102 is also provided with a positioning groove 110 that cooperates with the positioning stop ear 111 on the outer side of the ultrasonic transducer 105 .

[0022] The induction heating system 20 includes an electromagnetic induction heater 201, a magnetic induction heating coil 202 and an infrared thermometer 203. The electromagnetic induction heater 201 is connected to the magnetic induction heating coil 202. The heating section of the magnetic induction heating coil 202 is installed on the periphery of the test piece 108. The infrared thermometer 203 is used to monitor the temperature of the test piece 108. The automatic water level control system 30 includes a water tank 301, a water stop valve 302 and a water pump 303. The water stop valve 302 is connected to a faucet installed on the water tank 301 through a water pipe, and the water pump 303 completes the communication between the water tank 301 and the electromagnetic induction heater 201. The central control system 40 includes a fatigue control system 401, an automatic temperature control system 402 and a linkage system 403. The fatigue control system 401 is connected to the ultrasonic generator 104 by signal, the automatic temperature control system 402 is connected to the electromagnetic induction heater 201 by signal, and the linkage system 403 connects the fatigue control system 401 and the automatic temperature control 402 by signal through an acquisition card.

[0023] The above-mentioned automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue test device sample method comprises the following steps: The uniaxial ultra-high cycle fatigue test system 10 is fixed on the bracket through the ultrasonic transducer fixing plate 102, and the test piece 108 is connected to the extension rod 107 through bolts; the ultrasonic generator 104 receives the signal of the fatigue control system 401 in the central control system 40 through wired connection, and then inputs it to the ultrasonic transducer 105, and the ultrasonic transducer 105 converts the received ultrasonic signal into mechanical displacement, which is amplified by the displacement amplifier 106 and then transmitted to the test piece 108 through the extension rod 107, so that the test piece 108 undergoes a uniaxial fatigue test; The induction heating system 20 applies current to the magnetic induction heating coil 202 to change the magnetic field, and the magnetic field causes the test piece 108 to generate heat due to eddy current effect and hysteresis effect; the magnetic induction heating coil 202 is aligned with the center of the test piece 108, and the infrared thermometer 203 is aligned with the middle position of the test piece 108; The water of the automatic water level control system 30 flows from the faucet into the water tank 301 through the water stop valve 302, and the water in the water tank 301 enters the electromagnetic induction heater 201 through the water pump 303. When the water in the water tank 301 is higher than the water level line, the water stop valve 302 is closed, and the water pump 303 is still in working state, which will cause the water level to drop. When the water level drops below the water level line, the water stop valve 302 is opened again, and the operation is repeated. The fatigue control system 401 in the central control system 40 can start the uniaxial ultra-high cycle fatigue test system 10 by controlling the ultrasonic generator 104. The experimental stress is set in the fatigue control system 401. When the test piece 108 breaks, causing the feedback frequency to exceed the range of 20±0.5KHz, the ultrasonic generator 104 is automatically turned off and the signal is transmitted to the fatigue control system 401 in the central control system 40; the automatic temperature control system 402 in the central control system 40 controls the on / off of the induction heating system 20 through a relay, and the temperature output by the infrared thermometer 203 in the induction heating system 20 is converted into a voltage through an acquisition card, and the voltage value corresponds to the temperature value one by one, and the voltage is then transmitted to the relay through the automatic temperature control system 402; When the heating temperature is higher than the set temperature, the voltage entering the automatic temperature control system 402 is higher than the voltage corresponding to the set temperature. At this time, the automatic temperature control 402 will close the relay to turn off the induction heating system 20. When the temperature drops below the set temperature, the automatic temperature control system 402 will open the relay to turn on the induction heating system 20, and the temperature difference is controlled within ±2°C. The linkage system 403 in the central control system 40 and the fatigue control system 401 in the central control system 40 transmit the received signal of the fracture of the test piece 108 to the acquisition card by changing the voltage. After the working voltage collected by the acquisition card is changed, the signal is transmitted to the automatic temperature control system 402. The automatic temperature control system 402 detects the voltage change and automatically cuts off the transmission of the electrical signal through the relay, thereby shutting down the induction heating system 20, and finally stopping heating when the test piece 108 is fractured to prevent oxidation of the fracture.

[0024] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue testing device, characterized in that: It includes a uniaxial ultra-high cycle fatigue test system (10), an induction heating system (20), an automatic water level control system (30) and a central control system (40); The uniaxial ultra-high cycle fatigue test system (10) comprises a column (101), an ultrasonic transducer fixing plate (102), a base (103), an ultrasonic generator (104), an ultrasonic transducer (105), a displacement amplifier (106), an extension rod (107) and a test piece (108); three columns are provided, the three columns (101) and the base (103) and the ultrasonic transducer fixing plate (102) form a bracket, the ultrasonic transducer (105) is placed on the upper end of the ultrasonic transducer fixing plate (102), the ultrasonic generator (104) and the ultrasonic transducer (105) are connected by wire, and the ultrasonic transducer (105) and the displacement amplifier (106), the extension rod (107) and the test piece (108) are connected in sequence by bolts; The induction heating system (20) comprises an electromagnetic induction heater (201), a magnetic induction heating coil (202) and an infrared thermometer (203), wherein the electromagnetic induction heater (201) is connected to the magnetic induction heating coil (202), a heating section of the magnetic induction heating coil (202) is installed on the periphery of the test piece (108), and the infrared thermometer (203) is used to monitor the temperature of the test piece (108); The automatic water level control system (30) comprises a water tank (301), a water stop valve (302) and a water pump (303); the water stop valve (302) is connected to a faucet installed on the water tank (301) via a water pipe, and the water pump (303) completes the communication between the water tank (301) and the electromagnetic induction heater (201); The central control system (40) comprises a fatigue control system (401), an automatic temperature control system (402) and a linkage system (403); the fatigue control system (401) is signal-connected to an ultrasonic generator (104); the automatic temperature control system (402) is signal-connected to an electromagnetic induction heater (201); and the linkage system (403) connects the fatigue control system (401) and the automatic temperature control system (402) via an acquisition card.

2. The automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue testing device according to claim 1, characterized in that: The ultrasonic transducer fixing plate (102) is a circular ring structure, and the outer diameter of the ultrasonic transducer fixing plate (102) is the same as the outer diameter of the base (103).

3. The automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue testing device according to claim 1, characterized in that: The ultrasonic transducer (105) is clamped in the ultrasonic transducer fixing plate (102).

4. The automatic temperature-controlled uniaxial high-temperature ultra-high cycle fatigue testing device according to claim 1, characterized in that: The ultrasonic transducer fixing plate (102) is provided with a bolt hole (109) that cooperates with the column (101), and the ultrasonic transducer fixing plate (102) is also provided with a positioning groove (110) that cooperates with a positioning stop ear (111) on the outside of the ultrasonic transducer (105).

5. A sample method for a uniaxial high temperature ultra-high cycle fatigue test device with automatic temperature control according to any one of claims 1 to 4, characterized in that: The following steps are involved: The uniaxial ultra-high cycle fatigue test system (10) is fixed on a bracket via an ultrasonic transducer fixing plate (102), and the test piece (108) is connected to an extension rod (107) via bolts; the ultrasonic generator (104) receives a signal from a fatigue control system (401) in a central control system (40) via a wired connection, and then inputs the signal into the ultrasonic transducer (105); the ultrasonic transducer (105) converts the received ultrasonic signal into a mechanical displacement, and the mechanical displacement is amplified by a displacement amplifier (106) and then transmitted to the test piece (108) via an extension rod (107), so that the test piece (108) undergoes a uniaxial fatigue test; The induction heating system (20) applies current to the magnetic induction heating coil (202) to change the magnetic field, and the magnetic field causes the test piece (108) to generate heat due to eddy current effect and hysteresis effect; the magnetic induction heating coil (202) is aligned with the central part of the test piece (108), and the infrared thermometer (203) is aligned with the middle position of the test piece (108); The water of the automatic water level control system (30) flows from the faucet into the water tank (301) through the water stop valve (302), and the water in the water tank (301) enters the electromagnetic induction heater (201) through the water pump (303). When the water in the water tank (301) is higher than the water level line, the water stop valve (302) is closed. At this time, the water pump (303) is still in a working state, which will cause the water level to drop. When the water level drops below the water level line, the water stop valve (302) is opened again, and the operation is repeated. The fatigue control system (401) in the central control system (40) can start the uniaxial ultra-high cycle fatigue test system (10) by controlling the ultrasonic generator (104). The experimental stress is set in the fatigue control system (401). When the test piece (108) breaks, causing the feedback frequency to exceed the range of 20±0.5KHz, the ultrasonic generator (104) is automatically turned off and transmits a signal to the fatigue control system (401) in the central control system (40). The automatic temperature control system (402) in the central control system (40) controls the on / off of the induction heating system (20) through a relay. The temperature output by the infrared thermometer (203) in the induction heating system (20) is converted into a voltage through an acquisition card. The voltage value corresponds to the temperature value one by one. The voltage is then transmitted to the relay through the automatic temperature control system (402). When the heating temperature is higher than the set temperature, the voltage entering the automatic temperature control system (402) is higher than the voltage corresponding to the set temperature, and the automatic temperature control (402) will turn off the relay to turn off the induction heating system (20). When the temperature drops below the set temperature, the automatic temperature control system (402) will turn on the relay to turn on the induction heating system (20); The linkage system (403) in the central control system (40) and the fatigue control system (401) in the central control system (40) transmit the received signal of the fracture of the test piece (108) to the acquisition card by changing the voltage. After the working voltage collected by the acquisition card is changed, the signal is transmitted to the automatic temperature control system (402). When the automatic temperature control system (402) detects the voltage change, it automatically cuts off the transmission of the electrical signal through the relay, thereby shutting down the induction heating system (20), and finally achieving the effect of stopping heating when the test piece (108) is fractured, thereby preventing oxidation of the fracture surface.

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