Temperature calibration system and calibration method for high-temperature ultrasonic fatigue equipment

Abstract

The invention belongs to the technical field of performance test equipment calibration, and particularly relates to a temperature calibration system and method for high-temperature ultrasonic fatigue equipment, and the system comprises an induction heating device, a sample fixing device, a thermocouple, a temperature and humidity inspection instrument, an infrared thermometer, a temperature controller, and a data processing module. A constant-temperature area of the induction heating coil is accurately aligned with a gauge length section of a tested sample, a thermocouple tip is fixed to the geometric center of the gauge length section of the sample through a high-temperature asbestos rope, and the infrared thermometer is installed in the axis direction of the sample so that a light spot of the infrared thermometer can coincide with the thermocouple tip. Temperature data of an infrared thermometer and a thermocouple are synchronously collected, a deviation value is calculated, and when the temperature exceeds + / -3 DEG C, compensation parameters of a temperature controller are automatically adjusted, so that in-situ rapid and accurate high-temperature ultrasonic fatigue test temperature calibration is realized. According to the invention, the tested sample is used as a standard radiation source for temperature calibration, and the method is suitable for temperature calibration when high-temperature ultrasonic fatigue performance testing is carried out on all metal materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of performance test equipment calibration, in particular to a temperature calibration system and method for high-temperature ultrasonic fatigue equipment. BACKGROUND

[0002] The high-temperature ultrasonic fatigue test technology is a common method for testing the fatigue performance of a material by implementing high-temperature ultrasonic fatigue loading on the tested sample. Up to now, there is no standard for this test method, and there is no specification for the test temperature and temperature calibration method. The sample is generally heated by induction heating in this technology, but the temperature test of the sample has limitations. The direct contact of the thermocouple for temperature measurement with the tested sample will induce stress concentration at the contact point of the sample under the condition of high-temperature ultrasonic fatigue loading, which will cause the sample to fatigue fracture too early and cannot correctly evaluate the fatigue performance of the material. Therefore, a non-contact infrared thermometer is usually used to measure the heating temperature of the tested sample.

[0003] However, the temperature measurement accuracy of the infrared thermometer is greatly affected by the processing state of the sample and the external environment, and its accuracy is much lower than that of the thermocouple, so temperature calibration before use is necessary. Currently, commercial infrared thermometers usually use a blackbody furnace as a standard radiation source for temperature calibration, but there is a significant difference in emissivity between the tested sample and the blackbody furnace, which directly affects the accuracy of the experimental temperature and the correctness of the fatigue performance evaluation; some people use a rod-shaped sample made of the same material as the tested sample as a radiation source for experimental temperature calibration. This scheme not only brings test errors due to the processing state of the tested sample and the standard sample, but also brings temperature measurement point position errors due to the replacement of the clamped sample.

[0004] Therefore, there is a lack of an effective scheme for in-situ and real-time temperature calibration directly to the tested sample itself under actual test conditions in the prior art, which seriously affects the accuracy and reliability of the high-temperature ultrasonic fatigue test results. It has become a technical problem to be solved in the field to develop a temperature calibration system and method that can overcome the above limitations. SUMMARY

[0005] The application aims to provide a temperature calibration system and method for a high-temperature ultrasonic fatigue performance test system, which can quickly and accurately calibrate the heating temperature of the high-temperature ultrasonic fatigue performance test sample in-situ.

[0006] The technical solution adopted by the application to achieve the above-mentioned purpose is: a temperature calibration system for high-temperature ultrasonic fatigue equipment, comprising: an induction heating device, a sample fixing device, a thermocouple, a temperature and humidity patrol instrument, an infrared thermometer, a temperature controller and a data processing module.

[0007] The induction heating device is composed of a power module, an induction heating coil and a heat insulation support, and the constant temperature zone of the induction heating coil is accurately aligned with the gauge length section of the test sample.

[0008] The sample fixing device is installed on the amplitude bar of the ultrasonic fatigue performance testing machine and is used for keeping the axial stress of the sample stable.

[0009] The positive and negative poles of the thermocouple are connected to the input end of the temperature and humidity patrol instrument, and the tip of the thermocouple is fixed to the geometric center position of the gauge length section of the sample by a high-temperature asbestos rope.

[0010] The infrared temperature measuring instrument is installed in the direction consistent with the sample axis, so that the temperature measuring spot is coincided with the tip of the thermocouple.

[0011] The temperature controller is electrically connected with the induction heating power supply and is used for adjusting the heating power in real time according to the temperature deviation.

[0012] The data processing module is connected with the signal of the infrared temperature measuring instrument and the temperature and humidity patrol instrument, and is used for realizing temperature data acquisition, deviation calculation and compensation control.

[0013] The data processing module comprises a data acquisition unit, a temperature deviation calculation unit, a control instruction generation unit and a data storage unit.

[0014] The data acquisition unit is in communication connection with the infrared temperature measuring instrument and the temperature and humidity patrol instrument, and is used for synchronously acquiring the contact type and non-contact type temperature data.

[0015] The temperature deviation calculation unit is used for time alignment and numerical comparison of the two groups of temperature signals, and the temperature deviation is calculated; when the calculation result exceeds the threshold of ±3℃, the control instruction generation unit automatically sends an adjustment signal to the temperature controller to change the output current of the induction heating coil to correct the heating power.

[0016] The data storage unit is used for saving the compensation parameters and calibration historical data of different target temperature points, providing correction reference for the subsequent high-temperature fatigue test process, and realizing multi-temperature zone adaptive compensation control.

[0017] The induction heating coil is installed on the high-temperature resistant insulation support, the center hole diameter of the coil matches the diameter of the sample, the coil can be adjusted in the axial and radial directions, the center point of the constant temperature zone of the coil is coincided with the geometric center of the gauge length section of the sample, and the outer side of the coil is provided with an annular heat insulation cover and a temperature protection layer, which are used for reducing the interference of heat radiation on the infrared temperature measuring signal.

[0018] The infrared temperature measuring instrument is installed on the outer wall of the test machine shell and is kept stable by the fixing support, and the diameter of the measuring spot is not more than one third of the diameter of the sample, so as to ensure that the temperature measuring area is concentrated.

[0019] The temperature and humidity inspector is provided with multi-channel input ports, one of which is used for connecting a standard thermocouple signal and the other is used for connecting an auxiliary check thermocouple;

[0020] The temperature and humidity inspector is internally provided with a cold end compensation module and a signal amplification circuit, which are used for eliminating the temperature measurement error caused by environmental temperature drift in a high temperature environment.

[0021] The thermocouple is a K-type or N-type thermocouple; before the system is used, the output of the thermocouple is linearly calibrated by a standard constant temperature furnace, and the temperature correction coefficient is input in the temperature and humidity inspector, so as to ensure that the measurement accuracy is better than ±1℃ in the temperature range of 300℃ to 900℃.

[0022] The mounting angle of the infrared temperature measuring instrument can be finely adjusted, so that the temperature measuring optical axis and the sample axis are less than 10°.

[0023] The probe of the infrared temperature measuring instrument is externally provided with a metal light shielding cylinder and a cooling sleeve, which are used for shielding environmental light interference and reducing the influence of thermal radiation on the optical element.

[0024] The analog voltage signal output by the infrared temperature measuring instrument is converted into a digital temperature value by an A / D conversion module, and is transmitted to a data processing module through a data bus; before the system is started, the infrared temperature measuring instrument is pre-adjusted according to the emissivity parameter of the measured material surface, so as to ensure that the temperature measurement range matches the actual radiation characteristics of the sample, and then the calibration accuracy is ensured.

[0025] A device temperature calibration method of a temperature calibration system for a high-temperature ultrasonic fatigue equipment, comprising the following steps:

[0026] Step S1: install the sample on the variable amplitude rod of the testing machine through the fixing device, so that the gauge length section is located in the constant temperature zone of the induction heating coil;

[0027] Step S2: power heating is performed, and the highest temperature point position of the heating zone is determined by observing the redness of the sample, and the coil position is adjusted so that the point coincides with the geometric center of the sample;

[0028] Step S3: after cooling, the hot junction of the thermocouple is fixed on the center of the sample by using a high-temperature asbestos rope, and the infrared temperature measuring instrument is adjusted so that the light spot coincides with the thermocouple;

[0029] Step S4: execute the temperature maintaining stage: set the target temperature and heat and maintain for 10 minutes, and then read the temperature data of the infrared temperature measuring instrument and the temperature and humidity inspector at the same time;

[0030] Step S5: import the collected two groups of data into the data processing module, calculate the deviation value at each time, and if the deviation exceeds ±3℃, adjust the compensation parameters of the temperature controller until the calibration is completed.

[0031] In the step S5, the deviation value at each time is calculated, specifically:

[0032] The data processing module synchronously acquires the readings of the infrared thermometer at fixed time intervals. Thermocouple readings from temperature and humidity monitoring instruments Data is paired using timestamps; temperature pairs from multiple consecutive time points are averaged to reduce random noise.

[0033] The formula for calculating the temperature deviation is:

[0034]

[0035] in, For infrared thermometer readings, This is the thermocouple reading;

[0036] when When the absolute value exceeds the set threshold ±3℃, the data processing module automatically generates a correction command, and adjusts the heating power of the induction heating coil or sets the temperature compensation parameters through the temperature controller.

[0037] During the calibration process, deviation data and correction times are recorded in real time to form a temperature compensation curve, enabling dynamic correction of the infrared thermometer.

[0038] During the heat preservation stage in step S4, the following stability determination steps are performed:

[0039] Once the heating temperature reaches 95% of the target temperature, the control system enters a slow-rise steady-state region, controlling the temperature change rate to less than 1℃ / min.

[0040] Once the temperature reaches the target value, multiple sets of temperature data are continuously measured. If the root mean square value of the temperature fluctuation is less than ±1℃ and this state is maintained for more than 3 minutes, the temperature is determined to have reached a stable state, and then the temperature data used for calibration is recorded.

[0041] Following step S5, the process also includes establishing a compensation model, specifically:

[0042] The data processing module processes the temperature deviation values ​​obtained from calibration at different target temperature points. Perform function fitting to establish a functional relationship between the temperature deviation and the set temperature. And generate a temperature-compensation value mapping table;

[0043] The temperature-compensation value mapping table is stored in the data storage unit and is used by the temperature controller to automatically call and compensate the readings of the infrared thermometer in real time during subsequent high-temperature ultrasonic fatigue tests.

[0044] It also includes environmental adaptive correction mechanisms, specifically:

[0045] The temperature calibration system carries out first calibration under reference environmental conditions to obtain a reference temperature deviation under the conditions ;

[0046] When subsequent calibration is carried out under different environmental conditions, a temperature deviation under the current environment is obtained , and a relative environmental temperature difference coefficient is calculated as:

[0047]

[0048] wherein, is the relative environmental temperature difference coefficient, is the current environmental temperature deviation, is the reference temperature deviation;

[0049] The temperature calibration system records different environmental temperatures and corresponding values, and establishes an environmental temperature-coefficient query table;

[0050] When the temperature calibration system monitors that the difference between the current environmental temperature and the reference environmental temperature exceeds a set threshold value, the corresponding value is automatically called from the query table to correct the reading of the infrared temperature measuring instrument or the preset temperature compensation value.

[0051] The present application has the following beneficial effects and advantages:

[0052] 1. The present application directly uses the test sample, and carries the commercial standard thermocouple and the temperature and humidity inspection instrument on the high-temperature ultrasonic fatigue performance testing machine, realizes the in-situ real-time monitoring and recording of the temperature deviation between the infrared temperature measuring instrument and the standard thermocouple, and conveniently and quickly compensates and controls the temperature deviation of the infrared temperature measuring instrument, solving the problem of insufficient temperature measurement accuracy of the infrared temperature measuring instrument in the high-temperature ultrasonic fatigue test process.

[0053] 2. The present application uses the test sample as a standard radiation source for temperature calibration, which is suitable for temperature calibration when testing the high-temperature ultrasonic fatigue performance of all metal materials.

[0054] 3. The present application realizes the automation and intelligentization of the calibration process, significantly improves the calibration efficiency and consistency. Through the integrated data processing module, the system can automatically execute synchronous acquisition of temperature data, real-time deviation calculation, and generation and sending of compensation instructions. This avoids the subjective error introduced by the experience difference of operators in traditional manual calibration, ensures the high repeatability of each calibration process and result, and greatly reduces the human intervention and time cost.

[0055] 4. This invention possesses environmentally adaptive long-term calibration capabilities, ensuring the sustained stability of measurement accuracy. By establishing an environmental temperature-coefficient lookup table, the system can automatically sense changes in environmental temperature and dynamically correct the infrared thermometer readings by invoking the corresponding compensation coefficients. This mechanism effectively suppresses measurement drift caused by fluctuations in the laboratory environment, enabling the system to maintain high measurement accuracy within ±3℃ during long-term use, greatly improving the reliability of the equipment and the long-term comparability of test data. Attached Figure Description

[0056] Figure 1 A schematic diagram showing the overlap between the thermocouple tip probe and the infrared thermometer spot position in this invention;

[0057] Figure 2 A schematic diagram of the equipment connection for the temperature calibration system of the high-temperature ultrasonic fatigue performance testing machine of the present invention. Detailed Implementation

[0058] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0059] like Figure 2 The diagram shown is a schematic of the equipment connection of the temperature calibration system for the high-temperature ultrasonic fatigue performance testing machine of the present invention. The temperature calibration system for the high-temperature ultrasonic fatigue equipment of the present invention includes: an induction heating device, a sample fixing device, a thermocouple, a temperature and humidity monitoring instrument, an infrared thermometer, a temperature controller, and a data processing module.

[0060] The induction heating device consists of a power module, an induction heating coil, and a heat insulation bracket. The constant temperature zone of the induction heating coil is precisely aligned with the gauge length of the test sample.

[0061] The specimen fixing device is installed on the amplitude transformer of the ultrasonic fatigue performance testing machine to maintain the stability of the specimen under axial force.

[0062] The positive and negative terminals of the thermocouple are connected to the input terminals of the temperature and humidity monitoring instrument, respectively, and the tip of the thermocouple is fixed to the geometric center of the gauge length of the sample by a high-temperature asbestos rope.

[0063] The infrared thermometer is installed in a direction consistent with the axis of the sample, so that its temperature measuring spot coincides with the tip of the thermocouple.

[0064] The temperature controller is electrically connected to the induction heating power supply and is used to adjust the heating power in real time according to the temperature deviation.

[0065] The data processing module is connected to the infrared thermometer and the temperature and humidity monitoring instrument to realize temperature data acquisition, deviation calculation and compensation control.

[0066] Data processing module

[0067] The data processing module comprises a data acquisition unit, a temperature deviation calculation unit, a control instruction generation unit and a data storage unit.

[0068] The data acquisition unit is in communication connection with the infrared temperature measuring instrument and the temperature and humidity inspection instrument respectively, and is used for synchronously collecting contact type and non-contact type temperature data.

[0069] The temperature deviation calculation unit is used for time alignment and numerical comparison of the two groups of collected temperature signals, and is used for calculating the temperature deviation; when the calculation result exceeds the threshold value of ±3℃, the control instruction generation unit automatically sends an adjustment signal to the temperature controller to change the output current of the induction heating coil to correct the heating power.

[0070] The data storage unit is used for saving compensation parameters and calibration historical data of different target temperature points, providing correction reference for subsequent high-temperature fatigue test process, and realizing multi-temperature zone adaptive compensation control.

[0071] As shown in Figure 1 , it is a schematic view of the coincidence of the thermocouple tip probe and the light spot position of the infrared temperature measuring instrument, the induction heating coil is installed on the high-temperature-resistant insulating support, the coil center aperture is matched with the sample diameter, the coil can be finely adjusted along the axial and radial directions, so that the center point of the coil constant temperature zone is coincided with the geometric center of the sample gauge length section; the outer side of the coil is provided with an annular heat shield and a temperature protection layer, which is used for reducing the interference of heat radiation on the infrared temperature measuring signal;

[0072] The infrared temperature measuring instrument is installed on the outer wall of the test machine shell, and is kept stable through the fixed support, and the measuring light spot diameter is not more than one third of the sample diameter, so as to ensure that the temperature measuring area is concentrated.

[0073] The temperature and humidity inspection instrument is provided with multi-channel input ports, one of which is used for connecting the standard thermocouple signal, and the other is used for connecting the auxiliary calibration thermocouple;

[0074] The temperature and humidity inspection instrument is provided with a cold end compensation module and a signal amplification circuit inside, which is used for eliminating the temperature measurement error caused by the environmental temperature drift in the high-temperature environment;

[0075] As shown in Figure 1 , the thermocouple is K-type or N-type thermocouple; before the system is used, the output of the thermocouple is linearly calibrated through a standard constant temperature furnace, and the temperature correction coefficient is input in the temperature and humidity inspection instrument, so as to ensure that the measurement accuracy is better than ±1℃ in the temperature range of 300℃ to 900℃.

[0076] The installation angle of the infrared temperature measuring instrument can be finely adjusted, so that the angle between the temperature measuring optical axis and the sample axis is less than 10°;

[0077] The probe of the infrared temperature measuring instrument is provided with a metal light shielding cylinder and a cooling sleeve, which is used for shielding the environmental light interference and reducing the influence of heat radiation on the optical element.

[0078] The analog voltage signal output by the infrared thermometer is converted into a digital temperature value by an A / D conversion module and transmitted to the data processing module through a data bus; the infrared thermometer is preset and adjusted according to the emissivity parameter of the surface of the measured material before the system is started, so as to ensure that the temperature measurement range matches the actual radiation characteristics of the sample, and then the calibration accuracy is ensured.

[0079] As shown in Figure 2 The temperature calibration method for the equipment based on the high-temperature ultrasonic fatigue equipment temperature calibration system comprises the following steps:

[0080] Step S1: The sample is installed on the amplitude lever of the testing machine through the fixing device, so that the gauge length section is located in the constant temperature zone of the induction heating coil;

[0081] Step S2: The heating is turned on, and the highest temperature point position of the heating zone is determined by observing the redness of the sample, and the coil position is adjusted so that the point coincides with the geometric center of the sample;

[0082] Step S3: After cooling, the thermocouple tips are fixed on the center of the sample by using high-temperature asbestos ropes, and the infrared thermometer is adjusted so that the light spot coincides with the thermocouple;

[0083] Step S4: The temperature maintaining phase is executed: the target temperature is set, and after heating and maintaining for 10 minutes, the temperature data of the infrared thermometer and the temperature and humidity inspection instrument are read at the same time;

[0084] In the temperature maintaining phase, the following stability determination steps are executed.

[0085] When the heating temperature reaches 95% of the target temperature, the control system enters the slow rise steady state zone, and the temperature change rate is controlled to be less than 1℃ / min;

[0086] When the temperature reaches the target value, a plurality of groups of temperature data are continuously measured, if the root mean square value of the temperature fluctuation is less than ±1℃ and the state is maintained for more than 3 minutes, it is determined that the temperature reaches the stable state, and then the temperature data used for calibration is recorded.

[0087] Step S5: The two groups of collected data are imported into the data processing module, the deviation value at each time is calculated, if the deviation exceeds ±3℃, the compensation parameter of the temperature controller is adjusted until the calibration is completed.

[0088] The deviation value at each time is calculated, and specifically:

[0089] The data processing module synchronously collects the readings of the infrared thermometer at a fixed time interval and the thermocouple readings read by the temperature and humidity inspection instrument , and the data is paired through the time stamp; the temperature pairs at a plurality of continuous times are averaged to reduce random noise;

[0090] The temperature deviation value calculation formula is:

[0091]

[0092] Wherein, is the infrared thermometer reading, is the thermocouple reading;

[0093] When the absolute value of the temperature deviation exceeds the set threshold ± 3℃, the data processing module automatically generates a correction instruction to adjust the heating power of the induction heating coil or set the temperature compensation parameter through the temperature controller.

[0094] During calibration, the deviation data and the correction times are recorded in real time to form a temperature compensation curve, and dynamic correction of the infrared thermometer is realized.

[0095] After step S5, a compensation model is also established, specifically:

[0096] The data processing module performs function fitting on the temperature deviation values obtained by calibration at different target temperature points , establishes a functional relationship between the temperature deviation and the set temperature , and generates a temperature-compensation value mapping table.

[0097] The temperature-compensation value mapping table is stored in the data storage unit, and is used to automatically call and compensate the reading of the infrared thermometer in real time by the temperature controller in subsequent high-temperature ultrasonic fatigue tests.

[0098] The present application also includes an environmental adaptability correction mechanism, specifically:

[0099] The temperature calibration system performs first calibration under reference environmental conditions to obtain the reference temperature deviation under the conditions .

[0100] When subsequent calibration is performed under different environmental conditions, the temperature deviation under the current environment is obtained , and the relative environmental temperature difference coefficient is calculated as:

[0101]

[0102] Wherein, is the relative environmental temperature difference coefficient, is the current environmental temperature deviation, is the reference temperature deviation;

[0103] The temperature calibration system records different environmental temperatures and corresponding values, and establishes an environmental temperature-coefficient query table;

[0104] ​When the temperature calibration system monitors that the difference between the current ambient temperature and the reference ambient temperature exceeds a set threshold, the corresponding value is automatically called from the lookup table to correct the reading of the infrared thermometer or the preset temperature compensation value.

[0105] Embodiment:

[0106] Commercial thermocouples (certificate number: RXJZ-20250613020) and temperature and humidity inspection instruments (certificate number: 202410607377) were selected as standard instruments for temperature calibration of the ultrahigh cycle fatigue performance test system, and one end of the thermocouple was connected to the temperature and humidity inspection instrument.

[0107] Hastelloy X alloy fatigue samples were selected as the measured fatigue samples, and the temperature calibration system and calibration steps are as follows:

[0108] (1) Connect the positive and negative electrodes of the thermocouple to the positive and negative terminals of the temperature and humidity inspection instrument, respectively;

[0109] (2) Fix the sample on the amplitude rod of the ultrasonic fatigue performance tester, then overlap the constant temperature zone of the induction heating coil with the gage length section of the sample, and power on the induction heating;

[0110] (3) Judge the heating condition of the sample by the color change of the sample, adjust the position of the induction coil to make the geometric center position of the sample as the hottest heating temperature point, and then stop heating;

[0111] (4) After the sample cools down, fix the thermocouple tip in the geometric center position of the gage length section of the sample with a high-temperature asbestos rope, and make the tip coincide with the light spot of the infrared thermometer (see Figure 1 ), Figure 2 is a schematic diagram of the temperature calibration system equipment connection of the high-temperature ultrasonic fatigue performance tester;

[0112] (5) Set the heating temperature to 300℃ on the temperature controller of the induction heater (the temperature calibration method for 600℃ and 900℃ is consistent with this), start heating, and after 10 minutes of temperature maintenance, measure the temperature of the sample surface, record the temperature display values of the infrared thermometer and the temperature and humidity inspection instrument respectively, measure 12 times at each temperature point, with an interval of 10 minutes, and calculate the temperature deviation value. The raw data is shown in Table 1, which is the recorded temperature table of the system temperature and humidity inspection instrument and the infrared thermometer at 300℃ (Tables 2 and 3 correspond to the temperature raw records at 600℃ and 900℃, respectively).

[0113] Table 1 Recorded temperature table of the system temperature and humidity inspection instrument and the infrared thermometer at 300℃

[0114]

[0115] Table 2. Temperature recorded by the system temperature and humidity patrol instrument and the infrared temperature measuring instrument at 600 DEG C.

[0116]

[0117] Table 3. Temperature recorded by the system temperature and humidity patrol instrument and the infrared temperature measuring instrument at 900 DEG C.

[0118]

[0119] (6) By calculating the temperature deviation of the original temperature measurement data, it is found that when heated to 300 DEG C, the temperature deviation is -1.1 DEG C; when heated to 600 DEG C, the temperature deviation is -1.0 DEG C; when heated to 900 DEG C, the temperature deviation is -0.7 DEG C. It is found that the temperature deviations of 300 DEG C, 600 DEG C and 900 DEG C measured are all less than the requirement of ±3 DEG C required by the standard JJG 276, so there is no need to adjust the induction heating equipment.

[0120] According to the specific implementation case of the present application, Hastelloy X alloy samples are used to verify the system at 300 DEG C, 600 DEG C and 900 DEG C. As shown in Tables 1-3, through 12 consecutive measurements with an interval of 10 minutes, the average temperature deviations at 300 DEG C, 600 DEG C and 900 DEG C are calculated to be -1.1 DEG C, -1.0 DEG C and -0.7 DEG C, respectively, which are significantly better than the allowable error range of ±3 DEG C specified in JJG 276-2009 regulation. The experimental results show that the system and method described in the present application can realize high-precision temperature calibration, and show good stability and repeatability at different temperature ranges, verifying the effectiveness and reliability of the system in practical application.

[0121] In summary, the high-temperature ultrasonic fatigue equipment temperature calibration system and method provided by the present application innovatively uses the tested sample itself as a radiation source, and combines in-situ synchronous measurement of thermocouples and infrared temperature measuring instruments to establish a complete temperature calibration and compensation system. The core advantage is that in-situ calibration under test conditions is realized, eliminating the emissivity difference problem of traditional blackbody furnace calibration; a compensation model is established through multi-temperature point calibration, with self-adaptive temperature compensation capability; an environmental adaptability correction mechanism is introduced, significantly improving the measurement stability under different environmental conditions. The system is convenient to operate and has high calibration efficiency, effectively solving the long-standing problem of temperature measurement accuracy in high-temperature ultrasonic fatigue testing, and providing reliable technical support for accurate evaluation of the high-temperature ultrahigh cycle fatigue performance of materials.

[0122] Those skilled in the art can understand that the above description is only the preferred embodiment of the present application, and the features described in various embodiments of the present disclosure and / or claims can be combined or combined, even if such combination or combination is not explicitly described in the present disclosure. It is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacement for part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0123] Although preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application. Obviously, those skilled in the art can make various modifications and changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and changes of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and changes.

Claims

1. A temperature calibration system for a high-temperature ultrasonic fatigue device, characterized in that, include: Induction heating device, sample fixing device, thermocouple, temperature and humidity monitoring instrument, infrared thermometer, temperature controller and data processing module; The induction heating device consists of a power module, an induction heating coil, and a heat insulation bracket. The constant temperature zone of the induction heating coil is precisely aligned with the gauge length of the test sample. The specimen fixing device is installed on the amplitude transformer of the ultrasonic fatigue performance testing machine to maintain the stability of the specimen under axial force. The positive and negative terminals of the thermocouple are respectively connected to the input terminal of the temperature and humidity monitoring instrument, and the tip of the thermocouple is fixed to the geometric center of the gauge length of the sample by a high-temperature asbestos rope. The infrared thermometer is installed in a direction consistent with the axis of the sample, so that its temperature measuring spot coincides with the tip of the thermocouple. The temperature controller is electrically connected to the induction heating power supply and is used to adjust the heating power in real time according to the temperature deviation. The data processing module is connected to the infrared thermometer and the temperature and humidity monitoring instrument to realize temperature data acquisition, deviation calculation and compensation control.

2. The temperature calibration system for a high-temperature ultrasonic fatigue device according to claim 1, characterized in that, The data processing module includes: a data acquisition unit, a temperature deviation calculation unit, a control command generation unit, and a data storage unit; The data acquisition unit is connected to the infrared thermometer and the temperature and humidity monitoring instrument to synchronously acquire contact and non-contact temperature data. The temperature deviation calculation unit is used to perform time alignment and numerical comparison of the two sets of temperature signals collected, and calculate the temperature deviation. When the calculation result exceeds the ±3℃ threshold, the control command generation unit automatically sends an adjustment signal to the temperature controller to change the output current of the induction heating coil to correct the heating power. The data storage unit is used to save compensation parameters and calibration history data at different target temperature points, providing a correction reference for subsequent high-temperature fatigue testing and realizing multi-temperature zone adaptive compensation control.

3. The temperature calibration system for a high-temperature ultrasonic fatigue device according to claim 1, characterized in that, The induction heating coil is mounted on a high-temperature resistant insulating support. The center aperture of the coil matches the diameter of the sample. The coil can be finely adjusted axially and radially so that the center point of the coil's constant temperature zone coincides with the geometric center of the sample's gauge length. An annular heat insulation cover and a temperature protection layer are provided on the outside of the coil to reduce the interference of thermal radiation on the infrared temperature measurement signal. The infrared thermometer is installed on the outer wall of the test machine housing. The optical axis is kept stable by a fixed bracket, and the diameter of its measuring spot does not exceed one-third of the sample diameter, thereby ensuring that the temperature measurement area is concentrated.

4. The temperature calibration system for a high-temperature ultrasonic fatigue device according to claim 1, characterized in that, The temperature and humidity monitoring instrument is equipped with multiple input ports, one of which is used to connect to a standard thermocouple signal, and the other is used to connect to an auxiliary calibration thermocouple. The temperature and humidity monitoring instrument is equipped with a cold junction compensation module and a signal amplification circuit, which are used to eliminate temperature measurement errors caused by environmental temperature drift in high-temperature environments. The thermocouples are either type K or type N. Before using the system, the thermocouple outputs are linearly calibrated using a standard constant temperature furnace, and a temperature correction coefficient is input into the temperature and humidity monitoring instrument to ensure that the measurement accuracy is better than ±1℃ in the temperature range of 300℃ to 900℃.

5. The temperature calibration system for a high-temperature ultrasonic fatigue device according to claim 1, characterized in that, The installation angle of the infrared thermometer can be finely adjusted so that the angle between its temperature measuring optical axis and the sample axis is less than 10°. The infrared thermometer is equipped with a metal light-shielding tube and a cooling sleeve on the outside of the probe to shield against ambient light interference and reduce the impact of heat radiation on optical components. The analog voltage signal output by the infrared thermometer is converted into a digital temperature value by the A / D conversion module and transmitted to the data processing module through the data bus. Before the system is started, the infrared thermometer is preset and adjusted according to the surface emissivity parameters of the material being tested to ensure that the temperature measurement range matches the actual radiation characteristics of the sample, thereby ensuring calibration accuracy.

6. A method for calibrating the temperature of a temperature calibration system for a high-temperature ultrasonic fatigue device according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Install the sample on the amplitude transformer of the testing machine using a fixing device, so that the gauge length is located within the constant temperature zone of the induction heating coil; Step S2: Heat the sample by powering on and observe the reddening of the sample to determine the location of the highest temperature point in the heating zone. Adjust the position of the coil so that this point coincides with the geometric center of the sample. Step S3: After cooling, fix the thermocouple tip to the center of the sample with a high-temperature asbestos rope, and adjust the infrared thermometer so that its light spot coincides with the thermocouple. Step S4: Perform the heat preservation stage: After setting the target temperature and heating and preserving for 10 minutes, simultaneously read the temperature data from the infrared thermometer and the temperature and humidity monitoring instrument. Step S5: Import the two sets of collected data into the data processing module, calculate the deviation value at each time point, and adjust the temperature controller compensation parameters if the deviation exceeds ±3℃ until the calibration is completed.

7. The equipment temperature calibration method for a temperature calibration system for high-temperature ultrasonic fatigue equipment according to claim 6, characterized in that, In step S5, the deviation value at each time point is calculated as follows: The data processing module synchronously acquires the readings of the infrared thermometer at fixed time intervals. Thermocouple readings from temperature and humidity monitoring instruments Data is paired using timestamps; temperature pairs from multiple consecutive time points are averaged to reduce random noise. The formula for calculating the temperature deviation is: ； in, For infrared thermometer readings, This is the thermocouple reading; when When the absolute value exceeds the set threshold ±3℃, the data processing module automatically generates a correction command and adjusts the heating power of the induction heating coil or sets the temperature compensation parameters through the temperature controller. During the calibration process, deviation data and correction times are recorded in real time to form a temperature compensation curve, enabling dynamic correction of the infrared thermometer.

8. The equipment temperature calibration method for a temperature calibration system for high-temperature ultrasonic fatigue equipment according to claim 6, characterized in that, During the heat preservation stage in step S4, the following stability determination steps are performed: when the heating temperature reaches 95% of the target temperature, the control system enters the slow-rise steady-state zone and controls the temperature change rate to less than 1℃ / min. Once the temperature reaches the target value, multiple sets of temperature data are continuously measured. If the root mean square value of the temperature fluctuation is less than ±1℃ and this state is maintained for more than 3 minutes, the temperature is determined to have reached a stable state, and then the temperature data used for calibration is recorded.

9. The equipment temperature calibration method for a temperature calibration system for high-temperature ultrasonic fatigue equipment according to claim 6, characterized in that, Following step S5, the process also includes establishing a compensation model, specifically: The data processing module processes the temperature deviation values ​​obtained from calibration at different target temperature points. Perform function fitting to establish a functional relationship between the temperature deviation and the set temperature. And generate a temperature-compensation value mapping table; The temperature-compensation value mapping table is stored in the data storage unit and is used by the temperature controller to automatically call and compensate the readings of the infrared thermometer in real time during subsequent high-temperature ultrasonic fatigue tests.

10. The equipment temperature calibration method for a temperature calibration system for a high-temperature ultrasonic fatigue device according to claim 6, characterized in that, It also includes environmental adaptive correction mechanisms, specifically: The temperature calibration system is initially calibrated under reference environmental conditions to obtain the reference temperature deviation under those conditions. ; When performing subsequent calibrations under different environmental conditions, the temperature deviation under the current environment is obtained. The relative ambient temperature difference coefficient is calculated as follows: ； in, This is the relative ambient temperature difference coefficient. This is due to the current ambient temperature deviation. Reference temperature deviation; The temperature calibration system records different ambient temperatures and their corresponding values. Values ​​were calculated, and an ambient temperature-coefficient lookup table was created. When the temperature calibration system detects that the difference between the current ambient temperature and the reference ambient temperature exceeds a set threshold, it automatically retrieves the corresponding value from the lookup table. The value is used to correct the reading of the infrared thermometer or the preset temperature compensation value.

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