A quenching temperature prediction control method considering thermal hysteresis effect

Abstract

The present application relates to the control field of metal material heat treatment process, and discloses a quenching temperature estimation control method considering thermal hysteresis effect, which acquires thermal hysteresis time by collecting metal pipe temperature measurement value, thermal physical property parameter, structure parameter and quenching medium temperature, establishes quenching cooling thermal hysteresis model; extracts the heat exchange control parameter of historical output based on the thermal hysteresis time, carries out integral calculation on it in the hysteresis time interval, and outputs integral estimation value; then, in combination with the thermal hysteresis model, temperature measurement value and integral estimation value, analyzes and calculates pipe temperature estimation value; compares the deviation of estimation value and reference value, generates temperature deviation switching coefficient; finally, comprehensively feedback controls the pipe temperature estimation value and temperature deviation switching coefficient, calculates the heat exchange control parameter value at the current time, and outputs corresponding control instruction, realizes active compensation of the influence of thermal hysteresis, improves quenching temperature control performance, and ensures the dynamic response and precision of quenching process temperature control.

Description

Technical Field

[0001] This invention relates to the field of control technology for heat treatment processes of metallic materials, and more specifically to a method for predicting and controlling quenching temperature considering thermal hysteresis effects. Background Technology

[0002] In the overall heat treatment process of metal pipes, the quenching and cooling process occupies an indispensable and crucial position. Its operational quality and control precision directly determine the final mechanical properties of the finished metal pipe. The core function of quenching and cooling is to effectively guide the expected transformation reaction of the metallographic structure inside the metal pipe through scientific, reasonable, and precisely controllable adjustment of the cooling rate, thereby enabling the finished pipe to meet the specific usage requirements of production. In actual industrial production, to ensure the quality stability and batch consistency of metal pipe products, high technical requirements are placed on the quenching and cooling control system. This system needs to have the ability to dynamically adjust the convective heat exchange coefficient during quenching, strictly controlling the temperature change trajectory of the metal pipe surface through real-time monitoring and dynamic adjustment, ensuring it precisely conforms to the preset cooling curve parameters.

[0003] In traditional metal tube quenching and cooling temperature control practices, the design of control strategies often has significant limitations. The core control logic typically relies solely on the detected temperature deviation at the current moment to directly set and adjust the convective heat exchange coefficient during quenching, without fully considering the potential impact of thermal hysteresis. In many conventional control schemes, this crucial factor is even ignored entirely. Thermal hysteresis, as an objective physical phenomenon during quenching and cooling, is related to various factors such as the tube's own thermal conductivity and the heat transfer efficiency of the quenching medium; it is not a negligible secondary disturbance. If the control strategy neglects the time period corresponding to thermal hysteresis and relies solely on control commands generated from instantaneous temperature deviations, the command response will inevitably be out of sync with the actual temperature change. This will prevent the timely and accurate reflection of the tube's true temperature state during quenching and cooling, causing the tube's temperature response trajectory to deviate from the preset cooling standard. Consequently, the dynamic tracking accuracy of the entire temperature control system will be significantly reduced, making it difficult to meet the process requirements of high-precision heat treatment.

[0004] This control deviation caused by thermal hysteresis does not exist in isolation, but accumulates continuously throughout the quenching and cooling process. When the accumulated deviation reaches a certain level and exceeds the reasonable fluctuation range allowed by the process design, it directly causes the quenching and cooling rate to deviate from the preset process window requirements, making it impossible to achieve the normal transformation of the metallographic structure inside the pipe. Abnormal fluctuations in the cooling rate often lead to uneven quality defects in the pipe structure, such as excessive softness or hardness. These structural defects directly damage the mechanical property stability of the finished pipe, causing key indicators such as hardness, strength, and toughness to fail to meet production standards, seriously affecting the overall quality of the finished pipe. In extreme cases, if the inaccurate cooling rate caused by the accumulation of hysteresis is severe, it may even lead to the entire batch of metal pipes being unqualified, ultimately causing a serious production accident of batch scrapping, resulting in unnecessary economic losses and production delays for the enterprise. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a quenching temperature prediction and control method that takes into account the thermal hysteresis effect, so as to solve the problems existing in the background art.

[0006] This invention provides the following technical solution: a method for predicting and controlling quenching temperature considering thermal hysteresis, comprising:

[0007] S1: Real-time acquisition of temperature measurement values, thermophysical parameters and structural parameters of metal pipes and temperature of quenching medium during quenching and cooling process, and acquisition of thermal hysteresis time of quenching and cooling process, thereby establishing quenching and cooling thermal hysteresis model;

[0008] S2: Based on the thermal hysteresis time, extract the historical output heat exchange control parameters within the thermal hysteresis time interval as historical data and perform integral calculation to output the integral estimate of the heat exchange control parameters;

[0009] S3: Based on the quenching cooling thermal hysteresis model, temperature measurement values, and integral prediction values, the predicted temperature of the pipe is calculated.

[0010] S4: Obtain the pipe temperature reference value, perform deviation analysis between the pipe temperature reference value and the pipe temperature prediction value, and obtain the temperature deviation switching coefficient;

[0011] S5: Perform comprehensive feedback control analysis on the pipe temperature prediction and temperature deviation switching coefficient to calculate the heat exchange control parameter value at the current moment, and finally output the corresponding control command based on the heat exchange control parameter value.

[0012] Preferably, S1 specifically includes:

[0013] During the quenching and cooling process of metal pipes, the temperature of the metal pipes is continuously and in real time collected by a temperature sensor, obtaining pipe temperature measurement values ​​at multiple consecutive moments, including the current time t. The sequence of collected pipe temperature measurements is processed, and synchronization and filtering noise reduction preprocessing are performed on the sequence. Based on the preprocessed pipe temperature measurement sequence, the rate of change of pipe temperature at the current time t is calculated by difference. Simultaneously, the quenching medium temperature at the current time t is obtained. The system retrieves the fixed thermal properties and structural parameters of the pipe, including the calibrated specific heat capacity *c*, and the structural parameters including the effective heat exchange area *s* and mass *m*. Furthermore, it reads the quenching convection heat exchange coefficient acting on the pipe, generated by the internal thermal control system. The numerical sequence at historical moments is used to simultaneously acquire the lag time of the quenching convection heat exchange coefficient caused by thermal inertia and medium flow transport delay. A quenching cooling thermal hysteresis model was established based on the energy conservation relationship of heat exchange to characterize the temperature change rate of the pipe. The dynamic relationship between the acquired parameters at the current moment can be expressed as follows: ,in, for The quenching convective heat exchange coefficient at time t, and the model expression is used to represent the influence of thermal hysteresis effect on the dynamic change of pipe temperature.

[0014] Preferably, S2 specifically includes:

[0015] Based on the thermal hysteresis time, historical output heat exchange control parameters within the thermal hysteresis time interval are extracted as historical data and integrated. The integral estimate of the heat exchange control parameters is output, where the heat exchange control parameters specifically refer to the quenching convection heat exchange coefficient. The specific calculation process is as follows:

[0016] Based on the obtained quenching convection heat exchange coefficient hysteresis time Extracting lag time intervals from the numerical sequence of quenching convection heat exchange coefficients at historical moments Historical data within, in terms of integral variables This represents the quenching convective heat transfer coefficient within the specified time interval. By performing integral calculations, the integral estimate of the quenching convection heat exchange coefficient over the lag interval is obtained. The calculation formula is as follows: ,in, For an integral infinitesimal element, for The convective heat transfer coefficient during quenching at any given time. The quenching convection heat transfer coefficient in the hysteresis interval Estimated points value over the specified time period.

[0017] Preferably, S3 specifically includes:

[0018] Based on the established quenching cooling thermal hysteresis model and the collected pipe temperature measurement value at the current time t And the integral estimate of the quenching convection heat exchange coefficient By estimating the integral value Substituting the term representing the hysteresis heat exchange effect into the thermal hysteresis model, the estimated pipe temperature is calculated. The specific calculation process is as follows: The measured pipe temperature at the current time t is... , quenching medium temperature The effective heat exchange area s of the pipe, the calibrated specific heat capacity c of the pipe, the mass m of the pipe, and the integral estimate. Substituting into the formula for calculating the pipe temperature estimate, we obtain the pipe temperature estimate at time t, which is expressed as: ,in, This is the estimated temperature of the pipe at time t.

[0019] Preferably, S4 specifically includes:

[0020] Obtain the pipe temperature reference signal value at time t. The calculated estimated pipe temperature at time t With the reference signal value Deviation analysis was performed, and the temperature deviation switching coefficient was calculated using a sign function. The specific calculation process was as follows: the estimated temperature of the pipe was... With reference signal value Substituting the difference into the sign function, the temperature deviation switching coefficient at time t is calculated. Its expression is , where the sign function Satisfy the following expression:

[0021] .

[0022] Preferably, S5 specifically includes:

[0023] Based on the calculated estimated pipe temperature at time t The obtained pipe temperature reference signal value at time t and temperature deviation switching coefficient The control law for the quenching convection heat exchange coefficient is constructed by combining the proportional feedback of the deviation between the estimated pipe temperature and the reference signal value, the switching feedback of the temperature deviation, and the superposition of these factors. The quenching convection heat exchange coefficient to be applied at the current moment is calculated according to this control law, and its expression is as follows: ,in, This is the proportional feedback coefficient for the estimated temperature of the pipe. The feedback coefficient is switched to estimate the pipe temperature, and the corresponding control command is output based on the quenching convection heat exchange coefficient to be applied at the current moment, so as to achieve active compensation of the temperature during the quenching cooling process.

[0024] The technical effects and advantages of this invention are as follows:

[0025] By establishing a quenching cooling process model with thermal hysteresis, an integral prediction of the quenching convection heat exchange coefficient over the hysteresis interval is constructed based on historical data. Furthermore, a prediction of the pipe temperature is established. A switching function module is then designed, and a control law for the quenching convection heat exchange coefficient with superimposed switching feedback is constructed to actively compensate for the effects of thermal hysteresis, ultimately improving the quenching temperature control performance. By constructing an integral prediction of the heat exchange coefficient over the hysteresis interval based on historical data and establishing a prediction of the pipe temperature, active compensation for the effects of thermal hysteresis is achieved. By constructing a control law for the convection heat exchange coefficient with superimposed switching feedback, both rapid convergence of the temperature prediction is ensured, and robustness to model uncertainties and external disturbances is enhanced, ensuring high-precision tracking control is maintained even under thermal hysteresis conditions. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method of the present invention.

[0027] Figure 2 This is a control framework diagram of the method of the present invention.

[0028] Figure 3 This is a schematic diagram of the experimental equipment for the method of the present invention.

[0029] Figure 4 This is a comparison chart of the quenching temperature control effects of the method of this invention and the proportional control method.

[0030] Figure 5 This is a comparison chart of the quenching temperature control errors of the method of this invention and the proportional control method. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The quenching temperature prediction and control method considering thermal hysteresis effect involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 The embodiment shown provides a quenching temperature prediction and control method considering thermal hysteresis, including:

[0033] S1: Real-time acquisition of temperature measurements, thermophysical parameters, structural parameters, and quenching medium temperature of metal pipes during quenching and cooling process, and acquisition of thermal hysteresis time of quenching and cooling process, thereby establishing a quenching and cooling thermal hysteresis model.

[0034] In this embodiment, S1 specifically includes:

[0035] During the quenching and cooling process of metal pipes, the temperature of the metal pipes is continuously and in real time collected by a temperature sensor, obtaining pipe temperature measurement values ​​at multiple consecutive moments, including the current time t. The sequence of collected pipe temperature measurements is processed, and synchronization and filtering noise reduction preprocessing are performed on the sequence. Based on the preprocessed pipe temperature measurement sequence, the rate of change of pipe temperature at the current time t is calculated by difference. Simultaneously, the quenching medium temperature at the current time t is obtained. The system retrieves the fixed thermal properties and structural parameters of the pipe, including the calibrated specific heat capacity *c*, and the structural parameters including the effective heat exchange area *s* and mass *m*. Furthermore, it reads the quenching convection heat exchange coefficient acting on the pipe, generated by the internal thermal control system. The numerical sequence at historical moments is used to simultaneously acquire the lag time of the quenching convection heat exchange coefficient caused by thermal inertia and medium flow transport delay. A quenching cooling thermal hysteresis model was established based on the energy conservation relationship of heat exchange to characterize the temperature change rate of the pipe. The dynamic relationship between the acquired parameters at the current moment can be expressed as follows: ,in, for The quenching convective heat exchange coefficient at time t, and the model expression is used to represent the influence of thermal hysteresis effect on the dynamic change of pipe temperature.

[0036] S2: Based on the thermal hysteresis time, extract the historical output heat exchange control parameters within the thermal hysteresis time interval as historical data and perform integral calculation to output the integral estimated value of the heat exchange control parameters.

[0037] In this embodiment, S2 specifically includes:

[0038] Based on the thermal hysteresis time, historical output heat exchange control parameters within the thermal hysteresis time interval are extracted as historical data and integrated. The integral estimate of the heat exchange control parameters is output, where the heat exchange control parameters specifically refer to the quenching convection heat exchange coefficient. The specific calculation process is as follows:

[0039] Based on the obtained quenching convection heat exchange coefficient hysteresis time Extracting lag time intervals from the numerical sequence of quenching convection heat exchange coefficients at historical moments Historical data within, in terms of integral variables This represents the quenching convective heat transfer coefficient within the specified time interval. By performing integral calculations, the integral estimate of the quenching convection heat exchange coefficient over the lag interval is obtained. The calculation formula is as follows: ,in, For an integral infinitesimal element, for The convective heat transfer coefficient during quenching at any given time. The quenching convection heat transfer coefficient in the hysteresis interval Estimated points value over the specified time period.

[0040] S3: Based on the quenching cooling thermal hysteresis model, temperature measurement values, and integral prediction values, the predicted temperature of the pipe is calculated.

[0041] In this embodiment, S3 specifically includes:

[0042] Based on the established quenching cooling thermal hysteresis model and the collected pipe temperature measurement value at the current time t And the integral estimate of the quenching convection heat exchange coefficient By estimating the integral value Substituting the term representing the hysteresis heat exchange effect into the thermal hysteresis model, the estimated pipe temperature is calculated. The specific calculation process is as follows: The measured pipe temperature at the current time t is... , quenching medium temperature The effective heat exchange area s of the pipe, the calibrated specific heat capacity c of the pipe, the mass m of the pipe, and the integral estimate. Substituting into the formula for calculating the pipe temperature estimate, we obtain the pipe temperature estimate at time t, which is expressed as: ,in, This is the estimated temperature of the pipe at time t.

[0043] S4: Obtain the pipe temperature reference value, perform deviation analysis between the pipe temperature reference value and the pipe temperature prediction value, and obtain the temperature deviation switching coefficient.

[0044] In this embodiment, S4 specifically includes:

[0045] Obtain the pipe temperature reference signal value at time t. The calculated estimated pipe temperature at time t With the reference signal value Deviation analysis was performed, and the temperature deviation switching coefficient was calculated using a sign function. The specific calculation process was as follows: the estimated temperature of the pipe was... With reference signal value Substituting the difference into the sign function, the temperature deviation switching coefficient at time t is calculated. Its expression is , where the sign function Satisfy the following expression:

[0046] .

[0047] S5: Perform comprehensive feedback control analysis on the pipe temperature prediction and temperature deviation switching coefficient to calculate the heat exchange control parameter value at the current moment, and finally output the corresponding control command based on the heat exchange control parameter value.

[0048] In this embodiment, S5 specifically includes:

[0049] Based on the calculated estimated pipe temperature at time t The obtained pipe temperature reference signal value at time t and temperature deviation switching coefficient The control law for the quenching convection heat exchange coefficient is constructed by combining the proportional feedback of the deviation between the estimated pipe temperature and the reference signal value, the switching feedback of the temperature deviation, and the superposition of these factors. The quenching convection heat exchange coefficient to be applied at the current moment is calculated according to this control law, and its expression is as follows: ,in, This is the proportional feedback coefficient for the estimated temperature of the pipe. The feedback coefficient is switched to estimate the pipe temperature, and the corresponding control command is output based on the quenching convection heat exchange coefficient to be applied at the current moment, so as to achieve active compensation of the temperature during the quenching cooling process.

[0050] It should be specifically noted that the quenching convection heat transfer coefficient to be applied at the current moment needs to be calculated. The control system then uses this as the target setpoint. Since there is a known mapping relationship between the convective heat exchange coefficient and physical quantities such as the flow rate, volume, or pressure of the quenching medium, the required pump speed, solenoid valve opening, and other specific actuator parameters are calculated by looking up tables or solving inverse functions, and corresponding control commands are output to the actuators. The actuators change the flow state of the quenching medium, thereby making the actual convective heat exchange coefficient on the pipe surface approach the calculated target value. This enables proactive compensation for temperature deviations caused by thermal hysteresis.

[0051] Example 1: Validation of Quenching Temperature Prediction and Control Method Based on Simulation Experiment

[0052] The simulation uses the first-order Euler method to discretize the system dynamics, with a sampling step size of 0.01 seconds and a simulation duration of 500 seconds. Considering the quenching and cooling process of a certain type of metal pipe, its physical parameters are set as follows: effective heat exchange area of ​​the pipe... (rice 2 Effective specific heat capacity of pipe (Joules / (kg*Kelvin)), Pipe quality (kg), quenching medium temperature (°C), the initial temperature of the pipe is 1000 (°C), and the lag time of the quenching convection heat exchange coefficient under the thermal hysteresis effect. (seconds). The pipe temperature must be set according to the exponential cooling curve to meet process requirements. The pipe temperature reference signal value is:

[0053] ,

[0054] Selecting the proportional feedback coefficient for pipe temperature prediction Pipe temperature prediction switching feedback coefficient To highlight the compensation effect of this invention, a proportional control method was set as a control group, and the proportional feedback coefficient was also selected as 8.

[0055] Simulation Result Analysis

[0056] The simulation results are as follows Figure 4 and Figure 5 As shown. Figure 4 This paper compares the temperature control effects of the method of this invention and the proportional control method, where the dotted line represents the method of this invention, the solid line represents the proportional control method, and the dashed line represents the pipe temperature reference signal value. Figure 4 It can be seen that the method of the present invention can quickly and accurately track the pipe temperature reference signal value, and the two operating curves are closer, while the proportional control method has obvious lag and overshoot, and the dynamic response is slower. Figure 5 Temperature tracking error curves for two methods are presented, where the dotted line represents the method of this invention, and the solid line represents the proportional control method. Figure 5 It can be seen that the maximum absolute temperature tracking error of the proportional control method reaches 137.8 degrees Celsius, while the maximum absolute temperature tracking error of the method of the present invention reaches 60.0 degrees Celsius. Furthermore, the absolute temperature tracking error of the method of the present invention is less than 10 degrees Celsius after 190 seconds of system operation; however, the absolute temperature tracking error of the proportional control method decays slowly, and the temperature tracking error is still greater than 20 degrees Celsius after 400 seconds of system operation.

[0057] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for predicting and controlling quenching temperature considering thermal hysteresis, characterized in that, include: S1: Real-time acquisition of temperature measurement values, thermophysical parameters and structural parameters of metal pipes and temperature of quenching medium during quenching and cooling process, and acquisition of thermal hysteresis time of quenching and cooling process, thereby establishing quenching and cooling thermal hysteresis model; S2: Based on the thermal hysteresis time, extract the historical output heat exchange control parameters within the thermal hysteresis time interval as historical data and perform integral calculation to output the integral estimated value of the heat exchange control parameters; S3: Based on the quenching cooling thermal hysteresis model, temperature measurement values, and integral prediction values, the predicted temperature of the pipe is calculated. S4: Obtain the pipe temperature reference value, perform deviation analysis between the pipe temperature reference value and the pipe temperature prediction value, and obtain the temperature deviation switching coefficient; S5: Perform comprehensive feedback control analysis on the pipe temperature prediction and temperature deviation switching coefficient to calculate the heat exchange control parameter value at the current moment, and finally output the corresponding control command based on the heat exchange control parameter value.

2. The quenching temperature prediction and control method considering thermal hysteresis effect according to claim 1, characterized in that, S1 specifically includes: During the quenching and cooling process of metal pipes, the temperature of the metal pipes is continuously and in real time collected by a temperature sensor, obtaining pipe temperature measurement values ​​at multiple consecutive moments, including the current time t. The sequence of collected pipe temperature measurements is processed, and synchronization and filtering noise reduction preprocessing are performed on the sequence. Based on the preprocessed pipe temperature measurement sequence, the rate of change of pipe temperature at the current time t is calculated by difference. Simultaneously, the quenching medium temperature at the current time t is obtained. The system retrieves the fixed thermal properties and structural parameters of the pipe, including the calibrated specific heat capacity *c*, and the structural parameters including the effective heat exchange area *s* and mass *m*. Furthermore, it reads the quenching convection heat exchange coefficient acting on the pipe, generated by the internal thermal control system. The numerical sequence at historical moments is used to simultaneously acquire the lag time of the quenching convection heat exchange coefficient caused by thermal inertia and medium flow transport delay. A quenching cooling thermal hysteresis model was established based on the energy conservation relationship of heat exchange to characterize the temperature change rate of the pipe. The dynamic relationship between the acquired parameters at the current moment can be expressed as follows: ,in, for The quenching convective heat exchange coefficient at time t, and the model expression is used to represent the influence of thermal hysteresis effect on the dynamic change of pipe temperature.

3. The quenching temperature prediction and control method considering thermal hysteresis effect according to claim 2, characterized in that, S2 specifically includes: Based on the thermal hysteresis time, historical output heat exchange control parameters within the thermal hysteresis time interval are extracted as historical data and integrated. The integral estimate of the heat exchange control parameters is output, where the heat exchange control parameters specifically refer to the quenching convection heat exchange coefficient. The specific calculation process is as follows: Based on the obtained quenching convection heat exchange coefficient hysteresis time Extracting lag time intervals from the numerical sequence of quenching convection heat exchange coefficients at historical moments Historical data within, in terms of integral variables This represents the quenching convective heat transfer coefficient within the specified time interval. By performing integral calculations, the integral estimate of the quenching convection heat exchange coefficient over the lag interval is obtained. The calculation formula is as follows: ,in, For an integral infinitesimal element, for The convective heat transfer coefficient during quenching at any given time. The quenching convection heat transfer coefficient in the hysteresis interval Estimated points value over the specified time period.

4. The quenching temperature prediction and control method considering thermal hysteresis effect according to claim 3, characterized in that, S3 specifically includes: Based on the established quenching cooling thermal hysteresis model and the collected pipe temperature measurement value at the current time t And the integral estimate of the quenching convection heat exchange coefficient By estimating the integral value Substituting the term representing the hysteresis heat exchange effect into the thermal hysteresis model, the estimated pipe temperature is calculated. The specific calculation process is as follows: The measured pipe temperature at the current time t is used... , quenching medium temperature The effective heat exchange area s of the pipe, the calibrated specific heat capacity c of the pipe, the mass m of the pipe, and the integral estimate. Substituting into the formula for calculating the pipe temperature estimate, we obtain the pipe temperature estimate at time t, which is expressed as: ,in, This is the estimated temperature of the pipe at time t.

5. The quenching temperature prediction and control method considering thermal hysteresis effect according to claim 4, characterized in that, S4 specifically includes: Obtain the pipe temperature reference signal value at time t. The calculated estimated pipe temperature at time t With the reference signal value Deviation analysis was performed, and the temperature deviation switching coefficient was calculated using a sign function. The specific calculation process was as follows: the estimated temperature of the pipe was calculated... With reference signal value Substituting the difference into the sign function, the temperature deviation switching coefficient at time t is calculated. Its expression is , where the sign function Satisfy the following expression: 。 6. The quenching temperature prediction and control method considering thermal hysteresis effect according to claim 5, characterized in that, S5 specifically includes: Based on the calculated estimated pipe temperature at time t The obtained pipe temperature reference signal value at time t and temperature deviation switching coefficient The control law for the quenching convection heat exchange coefficient is constructed by combining the proportional feedback of the deviation between the estimated pipe temperature and the reference signal value, the switching feedback of the temperature deviation, and the superposition of these factors. The quenching convection heat exchange coefficient to be applied at the current moment is calculated according to this control law, and its expression is as follows: ,in, This is the proportional feedback coefficient for the estimated temperature of the pipe. The feedback coefficient is switched to estimate the pipe temperature, and the corresponding control command is output based on the quenching convection heat exchange coefficient to be applied at the current moment, so as to achieve active compensation of the temperature during the quenching cooling process.

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