A cooling control system and method for salt bath quenching of bearing parts

Abstract

A cooling control system and method for salt bath quenching of bearing parts, relates to the technical field of bearing heat treatment, wherein the cooling control system comprises: a micro simulation body placed in a salt bath tank, comprising a sealed sleeve and a thermocouple temperature sensor and an electric heating element enclosed in the sealed sleeve; the electric heating element is configured to actively heat the micro simulation body to a preset target temperature and then stop heating and naturally cool down; the thermocouple temperature sensor is configured to collect temperature data of the micro simulation body in the natural cooling process in real time. The cooling control system and method can dynamically monitor the quenching intensity of the salt bath quenching in real time, automatically generate a cooling characteristic curve through the collected temperature data, construct a special control model by using a self-learning algorithm, and finally automatically and accurately adjust the water supply according to the process requirements, so that the cooling rate of the bearing parts is stabilized in the ideal range.

Description

Technical Field

[0001] This invention relates to the field of bearing heat treatment technology, specifically to a cooling control system and method for salt bath quenching of bearing parts. Background Technology

[0002] Salt bath quenching is a critical heat treatment process in bearing manufacturing, and its cooling rate directly determines the metallographic transformation, hardness, toughness, and final service life of bearing parts. Currently, this process generally suffers from the following problems: First, there is a lack of effective real-time monitoring methods for the dynamic changes in salt bath composition (especially water content); second, the complex nonlinear relationship between molten salt fluidity and heat transfer efficiency is difficult to quantify and analyze; finally, the control of quenching intensity largely relies on the operator's experience to manually add water, resulting in poor control precision, low stability, and an inability to guarantee consistent product quality. Summary of the Invention

[0003] The purpose of this invention is to propose a cooling control system and method for salt bath quenching of bearing parts. The system performs real-time dynamic monitoring of the quenching intensity of salt bath quenching, automatically generates a cooling characteristic curve based on the collected temperature data, and constructs a dedicated control model using a self-learning algorithm. Finally, it automatically and accurately adjusts the water supply according to process requirements to keep the cooling rate of the bearing parts stable within the ideal range.

[0004] The technical solution adopted in this invention is: a cooling control system for salt bath quenching of bearing parts, comprising:

[0005] A miniature simulator, placed in a salt bath, includes a sealed sleeve and a thermocouple temperature sensor and an electric heating element enclosed within the sealed sleeve; the electric heating element is configured to actively heat the miniature simulator to a preset target temperature and then immediately stop heating and allow it to cool naturally; the thermocouple temperature sensor is configured to collect temperature data of the miniature simulator in real time during the natural cooling process.

[0006] A data acquisition module, which is connected to the thermocouple temperature sensor, is used to receive real-time temperature data.

[0007] The feature extraction module, connected to the data acquisition module, is used to acquire temperature data and establish the time-temperature curve of the micro-simulation during the natural cooling process, i.e., the cooling curve; extract the feature parameters of the cooling curve and calculate the real-time quenching intensity;

[0008] The relationship modeling module, which is connected to the feature extraction module, is used to establish and update the mapping relationship model between salt bath moisture content and real-time quenching intensity based on historically collected real-time quenching intensity and corresponding salt bath moisture content data.

[0009] The logic control center is connected to the feature extraction module and the relationship modeling module respectively. It is used to compare the current real-time quenching intensity with the preset target intensity, generate water replenishment control instructions based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity, and send the water replenishment control instructions to the actuator.

[0010] An actuator, connected to a logic control center, is used to receive water replenishment control commands and precisely replenish water to the salt bath tank according to the commands.

[0011] As a preferred embodiment, the sealing sleeve is made of corrosion-resistant stainless steel.

[0012] As a preferred embodiment, a data management module is also included, which is connected to the feature extraction module and the logic control center, for storing the cooling curve, quenching intensity and water replenishment records, and generating traceable electronic reports.

[0013] As a preferred embodiment, the logic control center is connected to the electric heating element and is used to send a start command to the electric heating element before collecting temperature data, so as to control the micro-simulation to heat up to the preset target temperature and then immediately stop heating.

[0014] As a preferred embodiment, a weight compensation module is also included, which is connected to the logic control center and is used to receive heat exchange parameters related to the heat exchange of bearing parts and the corresponding water replenishment amount; establish a linear compensation relationship between heat exchange parameters and water replenishment amount based on historically received data; dynamically compensate the current water replenishment amount of bearing parts based on the linear compensation relationship; and correct the water replenishment control command.

[0015] As a preferred embodiment, an HMI touchscreen is also included, which is connected to the feature extraction module and the logic control center for parameter setting and status monitoring.

[0016] A cooling control method for salt bath quenching of bearing parts includes the following steps:

[0017] The miniature simulator was placed in a salt bath.

[0018] After the electric heating element heats the miniature simulator to the target temperature, heating is stopped and the miniature simulator is allowed to cool naturally. Temperature data of the miniature simulator during the natural cooling process is collected in real time by a thermocouple temperature sensor.

[0019] Based on the temperature data, establish the time-temperature curve or cooling curve of the micro-simulation during the natural cooling process; extract the characteristic parameters of the cooling curve and calculate the real-time quenching intensity;

[0020] Based on historically collected real-time quenching intensity and corresponding salt bath moisture content data, a mapping relationship model between salt bath moisture content and real-time quenching intensity is established and updated.

[0021] The current real-time quenching intensity is compared with the preset target intensity. A water replenishment control command is generated based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity. Water is replenished to the salt bath according to the water replenishment control command.

[0022] As a preferred option, at least one of the following control modes is used for water replenishment in the salt bath: real-time water replenishment, fixed-cycle water replenishment, and water replenishment during the workpiece quenching window.

[0023] As a preferred embodiment, the characteristic parameters in the cooling curve include at least one of the following: the average cooling rate within a specific temperature range, the total time required for the temperature to naturally cool from a preset target temperature to the cooling termination temperature, and the derivative eigenvector of the cooling curve.

[0024] As a preferred embodiment, the water replenishment control command is generated using a PID control algorithm or a fuzzy control algorithm.

[0025] Compared with existing technologies, the beneficial effects of this invention are that, through the deep integration of hardware sensing, data-driven approaches, and intelligent decision-making, it completely changes the traditional salt bath quenching control mode that relies on human experience, bringing about significant technological progress:

[0026] 1. From "qualitative experience" to "quantitative data": Through high-precision probes and systems, real-time and quantitative monitoring of salt bath quenching intensity was achieved for the first time, transforming fuzzy process parameters into precise digital models and providing a scientific basis for quality control.

[0027] 2. From "manual and extensive" to "intelligent and precise": By utilizing a self-learning model and the precise logic control of the PLC, fully automatic and closed-loop management of water addition is achieved. The response speed is fast and the control accuracy is high, which fundamentally eliminates quality fluctuations caused by human factors and ensures the ultimate uniformity and stability of product performance.

[0028] 3. From "single and rigid" to "flexible and adaptable": Multiple configurable control modes and parameter settings enable a single system to flexibly adapt to various bearing specifications and quenching processes, greatly improving the versatility of the equipment and the flexibility of the production line.

[0029] 4. From “Result Verification” to “Process Traceability”: Comprehensive data recording and reporting functions enable traceability of the entire production process, which not only facilitates problem identification but also accumulates valuable data assets for continuous process optimization. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a perspective view of the miniature simulation object in this invention;

[0032] Figure 2 This is a schematic diagram of the end face of the micro-simulation in this invention;

[0033] Figure 3 This is a schematic diagram of the cooling control system in this invention;

[0034] Figure 4 A flowchart of the cooling control method in this invention.

[0035] Reference numerals: 1. Miniature simulator; 101. Sealing sleeve; 102. Thermocouple temperature sensor; 103. Electric heating element. Detailed Implementation

[0036] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0037] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0038] To more clearly describe the cooling control system and method used for salt bath quenching of bearing parts, see attached... Figure 1-4 This embodiment is described as follows:

[0039] like Figure 1-4 As shown, a cooling control system for salt bath quenching of bearing parts includes three main parts: a dedicated detection device, an intelligent control unit, and an actuator.

[0040] The miniature simulator 1 is a specialized detection device designed for high-temperature, highly corrosive salt bath environments. It is placed inside a salt bath tank and includes a sealing sleeve 101, a thermocouple temperature sensor 102, and an electric heating element 103 integrated within the sealing sleeve 101. The sealing sleeve 101 is made of corrosion-resistant stainless steel using a special process to ensure long-term stable operation in molten salt. The electric heating element 103 is a built-in heating element precisely controlled by a PLC, which can actively heat the miniature simulator 1 to a preset target temperature and then immediately stop heating and allow it to cool naturally. The thermocouple temperature sensor 102 is a high-precision temperature sensor that collects the temperature data of the miniature simulator 1 in real time during the active heating and natural cooling processes.

[0041] The unique feature of this miniature simulator 1 is that it is not a simple thermometer, but a simulator capable of actively performing a "heat-cooling" cycle. Miniature simulator 1 is equivalent to a "standard miniature workpiece," and its size, materials, and internal structure must be precisely calculated and calibrated to ensure that the temperature changes it measures accurately represent the cooling capacity of a real workpiece in a salt bath.

[0042] The intelligent control unit is responsible for signal acquisition, data processing, model calculation and control command generation, including a data acquisition module, a feature extraction module, a relationship modeling module, a logic control center / PLC, a human-machine interface, a data management module and a weight compensation module.

[0043] The data acquisition module is connected to the thermocouple temperature sensor to receive real-time temperature data.

[0044] The feature extraction module is connected to the data acquisition module to acquire temperature data and establish the time-temperature curve of the micro-simulation during the natural cooling process, i.e., the cooling curve; extract the feature parameters of the cooling curve and calculate the real-time quenching intensity;

[0045] The relationship modeling module is connected to the feature extraction module to establish and update the mapping relationship model between salt bath moisture content and real-time quenching intensity based on historically collected real-time quenching intensity and corresponding salt bath moisture content data.

[0046] The logic control center / PLC is connected to the electric heating element, the feature extraction module, and the relationship modeling module, respectively. It is used to send a start command to the electric heating element before collecting temperature data, so as to control the micro-simulation to heat up to the preset target temperature and then immediately stop heating; and to compare the current real-time quenching intensity with the preset target intensity, generate a water replenishment control command based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity, and send the water replenishment control command to the actuator.

[0047] The configuration and feature extraction module and the logic control center are connected to a human-machine interface module (HMI touch screen) for parameter setting, status monitoring and data visualization.

[0048] The data management module is connected to the feature extraction module and the logic control center to store cooling curves, quenching intensity and water replenishment records, and generate traceable electronic reports.

[0049] The weight compensation module is connected to the logic control center to receive heat exchange parameters (workpiece weight, surface area) related to the heat exchange of bearing parts and the corresponding water replenishment amount. Based on the historical data received, a linear compensation relationship between the heat exchange parameters and the water replenishment amount is established. Based on the linear compensation relationship, the current water replenishment amount of the bearing parts is dynamically compensated, and the water replenishment control command is corrected.

[0050] The actuator employs a high-precision electronic metering pump, which is connected to the logic control center to receive water replenishment control commands (pulse or analog signals) and precisely replenish water to the salt bath tank according to these commands. During water replenishment, the system obtains the amount and time of each replenishment. By accumulating the total water replenishment volume and combining it with experience regarding losses such as salt bath evaporation and workpiece carry-away, the system can estimate the theoretical water content of the current salt bath tank.

[0051] This invention also proposes a cooling control method for salt bath quenching of bearing parts, comprising the following steps:

[0052] Step 1: Preparation and Parameter Preset

[0053] After the system is powered on, the operator initializes the system via the HMI touchscreen and sets key process parameters, such as the simulated heating target temperature, the cooling process termination temperature, and the target quenching intensity value.

[0054] Step Two: Active Measurement and Data Acquisition

[0055] The system supports continuous measurement mode or periodic trigger measurement mode.

[0056] The miniature simulator is placed in a salt bath. Upon receiving a start command, the PLC controls the heating element within the probe to activate, actively and rapidly heating the probe from its current temperature to a preset target temperature (the target temperature is the set temperature the probe core needs to reach, typically the starting temperature for simulating workpiece quenching; the target temperature is higher than the current temperature of the salt bath). Heating is immediately stopped upon reaching the target temperature, and the temperature data of the miniature simulator during natural cooling is collected in real time by a thermocouple temperature sensor.

[0057] Step 3: Intensity Feature Extraction and Modeling Analysis

[0058] Feature Extraction: Based on temperature data, a time-temperature curve (i.e., cooling curve) is established for the entire process of natural cooling in the salt bath until the temperature drops to the desired final cooling temperature (a preset value, greater than or equal to the current temperature of the salt bath). The system analyzes the collected cooling curve and extracts feature parameters. These parameters can be: the average cooling rate within a specific temperature range, the total time required for the temperature to drop from the target heating temperature to the final cooling temperature, or a specific feature vector formed by the derivatives of the cooling curve. This calculated feature value is the real-time quenching intensity of the current salt bath.

[0059] Relationship Model Construction: The system collects historical data through multiple measurement cycles, and self-learns to establish and continuously correct the mapping relationship database or mapping relationship model of "salt bath moisture content - real-time quenching intensity". This model is the basis for the system to make intelligent decisions.

[0060] Step Four: Intelligent Decision-Making and Precise Execution

[0061] Decision: The PLC compares the real-time quenching intensity calculated in step three with the preset target intensity (target quenching intensity). Based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity, the PLC calculates the amount of water that needs to be added through a preset PID control algorithm or fuzzy control algorithm and generates a water replenishment control command.

[0062] For example, intelligent decision-making and precise execution specifically include the following steps:

[0063] Step 1: Preset the target intensity (H) target ): The operator sets it on the HMI, for example, 120°C / s (this is the average cooling rate in a specific high temperature range, such as from 800°C to 400°C).

[0064] Step 2: Current measured intensity (H) current Assume that the real-time intensity (real-time quenching intensity) measured by this micro-simulation is 110℃ / s.

[0065] Step 3: Mapping Relationship Model (already established through learning): Assume that the system has obtained a simplified model under the current operating conditions through learning:

[0066] H=k·W+b

[0067] Where: H is the quenching intensity (℃ / s); · indicates multiplication; W is the salt bath moisture content (relative unit, for example, it can be understood as "cumulative water replenishment equivalent liters"); k is the direct proportionality coefficient (for example, 0.5, indicating that for every 1 unit increase in moisture content, the intensity increases by 0.5℃ / s); b is the basic intensity (for example, 60, representing the theoretical intensity when the moisture content is 0); under the current salt bath temperature, composition, and flow conditions, moisture content is the main adjustable variable affecting the intensity, and the two are positively correlated (adding water increases the intensity).

[0068] Step 4: Current estimated water content (W) current (This refers to the current water content of the salt bath, calculated by the system based on previous water replenishment records and the model. Assume it to be 100 units.)

[0069] Step 5: Intensity Deviation Calculation

[0070] ΔH=H target -H current =120-110= +10℃ / s

[0071] A positive deviation indicates that the current cooling is too slow and water needs to be added to increase the intensity.

[0072] Step 6: Based on the model, calculate the target water content (W) required to achieve the target intensity. target )

[0073] According to the model formula H=k·W+b, we can obtain:

[0074] W target =(120-60) / 0.5=60 / 0.5=120 units

[0075] Step 7: Calculate the amount of water needed to be added (ΔW)

[0076] ΔW=W target -W current =120-100= +20 units

[0077] This means that, according to model calculations, the water content needs to be increased by 20 units to raise the intensity from the current 110℃ / s to the target 120℃ / s.

[0078] Step 8: Finely determine the amount of water to be replenished using a control algorithm (such as PID).

[0079] Directly using the model to calculate ΔW might be too "crude" because the model has errors and the system has inertia. Therefore, a PID (Proportional-Integral-Derivative) control algorithm is needed to make a more robust decision.

[0080] The proportionality (P) function is directly proportional to the deviation ΔH (+10℃ / s). Kp·ΔH will directly provide a basic water replenishment amount. Assuming the proportionality coefficient Kp is set to 0.3 (unit: water replenishment units / (℃ / s)), the proportional term output will be 0.3·10=3 units.

[0081] The function of the integral (I) is to accumulate historical bias. If the intensity measurements in the past have been consistently low, the integral term will become increasingly larger, thereby eliminating steady-state error and ensuring that the value eventually stabilizes at the target value. Assume the cumulative value of the integral term is 5 units.

[0082] The role of the differential (D) term: to predict and adjust based on the trend of current deviation changes (the rate of change of ΔH). If the intensity decreases rapidly, it will preemptively add more. Assume the differential term output is -1 unit this time (because it may be observed that the trend of intensity decrease is slowing down).

[0083] PID total output (value of this water replenishment command):

[0084] ΔW PID =P+I+D=3+5+(-1)=7 units.

[0085] Step 9: Perform hydration

[0086] The PLC sends the instruction to "replenish 7 units of water" to the actuator (such as a precision metering pump). The metering pump will then operate at a set flow rate for (7 units / pump flow rate) seconds to complete the water replenishment.

[0087] Multi-mode execution: The PLC selects the control mode according to the process, and the high-precision electronic metering pump receives the water replenishment control command to perform water addition operation to the salt bath tank. Its control modes include:

[0088] Closed-loop control mode based on intensity feedback: The water addition strategy is adjusted in real time directly based on the intensity deviation value;

[0089] Fixed-cycle water replenishment mode: serving as a basic guarantee;

[0090] Quenching production cycle linkage mode: synchronized with the workpiece quenching rhythm, water is added during specific window periods.

[0091] Composite intelligent mode: A combination of the above modes, for example, using a fixed cycle mode to maintain operations during non-production cycles and a closed-loop mode to fine-tune operations during production cycles.

[0092] Advanced features and improved accuracy

[0093] Data Management and Traceability: The system automatically stores all cooling curves, intensity values, water addition records, and alarm events, generating traceable electronic reports to provide data support for process optimization and quality auditing.

[0094] Weight compensation mechanism: To achieve higher control accuracy, the system is equipped with a workpiece weight input interface. The PLC can dynamically compensate and correct the calculated water addition amount based on the total weight and surface area of ​​each workpiece to offset the disturbance caused by the heat and moisture carried away by the workpiece.

[0095] For example, the weight compensation mechanism includes the following steps:

[0096] Step 1: Establishing an empirical formula: The system receives heat exchange parameters related to the heat exchange of bearing parts and the corresponding water replenishment amount. Through learning from historical data, it summarizes the linear compensation relationship between the compensation water amount and the workpiece weight and surface area. For example: Compensation water amount = 0.006·weight (kg) + 0.1·surface area (m²) 2 ).

[0097] Step 2: Real-time prediction and execution:

[0098] Before production, the operator enters the weight (e.g., 100kg) and surface area (e.g., 2.0m²) of the workpieces in this batch. 2 );

[0099] When the workpiece begins to enter the tank, the system dynamically compensates the current water supply of the bearing parts according to the linear compensation relationship, that is, it calculates the predicted compensation water supply (e.g., 0.8 liters) according to the formula.

[0100] Subsequently, the system adds 0.8 liters of water to the regular water replenishment. Water replenishment is usually carried out simultaneously with the workpiece entering the tank to offset the resulting thermal shock and moisture loss.

[0101] Step 3: Self-Optimization: After compensation, the system will measure the actual effect. If there is still a deviation, it will automatically fine-tune the coefficients in the compensation formula to make the next prediction more accurate.

[0102] This invention is equivalent to adding "feedforward control" capability to the system, thereby minimizing process fluctuations during production and significantly improving product consistency.

[0103] The parts not described in detail in the above embodiments are existing technologies.

[0104] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A cooling control system for salt bath quenching of bearing parts, characterized in that, include: A miniature simulator, placed in a salt bath, includes a sealed sleeve and a thermocouple temperature sensor and an electric heating element enclosed within the sealed sleeve. The electric heating element is configured to actively heat the miniature simulator to a preset target temperature and then immediately stop heating and allow it to cool naturally; the thermocouple temperature sensor is configured to collect the temperature data of the miniature simulator in real time during the natural cooling process. A data acquisition module, which is connected to the thermocouple temperature sensor, is used to receive real-time temperature data. The feature extraction module, connected to the data acquisition module, is used to acquire temperature data and establish the time-temperature curve of the micro-simulation during the natural cooling process, i.e., the cooling curve; extract the feature parameters of the cooling curve and calculate the real-time quenching intensity; The relationship modeling module, which is connected to the feature extraction module, is used to establish and update the mapping relationship model between salt bath moisture content and real-time quenching intensity based on historically collected real-time quenching intensity and corresponding salt bath moisture content data. The logic control center is connected to the feature extraction module and the relationship modeling module respectively. It is used to compare the current real-time quenching intensity with the preset target intensity, generate water replenishment control instructions based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity, and send the water replenishment control instructions to the actuator. An actuator, connected to a logic control center, is used to receive water replenishment control commands and precisely replenish water to the salt bath tank according to the commands.

2. A cooling control system for salt bath quenching of bearing parts according to claim 1, characterized in that: The sealing sleeve is made of corrosion-resistant stainless steel.

3. A cooling control system for salt bath quenching of bearing parts according to claim 1, characterized in that: It also includes a data management module, which is connected to the feature extraction module and the logic control center, for storing the cooling curve, quenching intensity and water replenishment records, and generating traceable electronic reports.

4. A cooling control system for salt bath quenching of bearing parts according to claim 1, characterized in that: The logic control center is connected to the electric heating element and is used to send a start command to the electric heating element before collecting temperature data, so as to control the micro-simulation to heat up to the preset target temperature and then immediately stop heating.

5. A cooling control system for salt bath quenching of bearing parts according to claim 1, characterized in that: It also includes a weight compensation module, which is connected to the logic control center, for receiving heat exchange parameters related to the heat exchange of bearing parts and the corresponding water replenishment amount; establishing a linear compensation relationship between heat exchange parameters and water replenishment amount based on historically received data; dynamically compensating the current water replenishment amount of bearing parts based on the linear compensation relationship; and correcting the water replenishment control command.

6. A cooling control system for salt bath quenching of bearing parts according to claim 1, characterized in that: It also includes an HMI touchscreen, which is connected to the feature extraction module and the logic control center for parameter setting and status monitoring.

7. A cooling control method utilizing the cooling control system according to any one of claims 1-6, characterized in that, Includes the following steps: The miniature simulator was placed in a salt bath. After the electric heating element heats the miniature simulator to the target temperature, heating is stopped and the miniature simulator is allowed to cool naturally. Temperature data of the miniature simulator during the natural cooling process is collected in real time by a thermocouple temperature sensor. Based on the temperature data, establish the time-temperature curve or cooling curve of the micro-simulation during the natural cooling process; extract the characteristic parameters of the cooling curve and calculate the real-time quenching intensity; Based on historically collected real-time quenching intensity and corresponding salt bath moisture content data, a mapping relationship model between salt bath moisture content and real-time quenching intensity is established and updated. The current real-time quenching intensity is compared with the preset target intensity. A water replenishment control command is generated based on the mapping relationship model and the deviation between the real-time quenching intensity and the preset target intensity. Water is replenished to the salt bath according to the water replenishment control command.

8. The cooling control method according to claim 7, characterized in that, The following control modes are used for water replenishment in the salt bath: real-time water replenishment, fixed-cycle water replenishment, and water replenishment during the workpiece quenching window.

9. The cooling control method according to claim 7, characterized in that, The characteristic parameters in the cooling curve include at least one of the following: the average cooling rate within a specific temperature range, the total time required for the temperature to naturally cool from the preset target temperature to the cooling termination temperature, and the derivative eigenvector of the cooling curve.

10. The cooling control method according to claim 7, characterized in that: The water replenishment control command is generated using a PID control algorithm or a fuzzy control algorithm.

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