Alloy steel wire spheroidizing annealing temperature difference compensation method and system

Abstract

The present application relates to the technical field of industrial heat treatment temperature control, and particularly relates to an alloy steel wire spheroidizing annealing temperature difference compensation method and system. The method obtains an inner layer representative temperature, an outer layer representative temperature and a target spheroidizing annealing temperature range of a steel wire coil, calculates a radial temperature difference and a temperature difference change state of a control period; determines an overall temperature rising demand or a radial uniform heating demand according to the relationship between the inner and outer layer temperatures and the target spheroidizing annealing temperature range, adjusts a heating power and a circulating air volume, and updates the radial temperature difference and a temperature difference convergence state; determines an effective holding starting point when the inner and outer layer temperatures are both in the target spheroidizing annealing temperature range, the radial temperature difference is not greater than a uniform heating threshold value and a continuous stable period is maintained, determines a compensation holding time length according to the radial temperature difference corresponding to the starting point, and generates an annealing completion state. The present application makes the overall temperature rising, radial uniform heating and holding timing correspond to the radial heat state of the steel wire coil, and reduces the holding connection deviation of the asynchronous temperature rising of the inner and outer layers.

Description

Technical Field

[0001] This invention relates to the field of industrial heat treatment temperature control technology, and in particular to a method and system for compensating for temperature differences during spheroidizing annealing of alloy steel wire. Background Technology

[0002] In the field of industrial heat treatment temperature control technology, alloy steel wire is usually loaded into a spheroidizing annealing furnace in coil form, and the heating, homogenization and holding processes are completed according to the preset heating curve, target spheroidizing annealing temperature range and holding time. Existing spheroidizing annealing furnaces usually adjust the heating power according to the temperature acquisition results in the furnace, and change the gas circulation state in the furnace with the help of a circulating fan. After reaching the set temperature or entering the preset process stage, the corresponding holding control is performed.

[0003] Because the steel wire coil has a radially stacked winding structure, the outer layer and the inner layer of the coil have different heat exchange paths and thermal response processes relative to the thermal environment inside the furnace. During the heating process, it is easy for the outer layer to reach or enter the target spheroidizing annealing temperature range, while the inner layer temperature is still in the heating state. If the existing solution mainly adjusts the heating power and circulating air volume based on the furnace temperature, a single temperature measuring position, or a preset heating program, it is difficult to switch between the overall heating control and the radial homogenization process of the coil in a timely manner according to the actual temperature state, and the temperature changes of the inner and outer layers of the coil are also difficult to keep in continuous correspondence with the subsequent control process.

[0004] In existing spheroidizing annealing processes, the holding time is usually started based on the furnace temperature reaching a set state, the pre-set process program entering the holding stage, or fixed time conditions. When the outer and inner layers of the coil are not heated synchronously, there may be a deviation between the above-mentioned timing start point and the actual heat homogenization state of the coil. Therefore, it is necessary to solve the problem of the difficulty in continuously connecting the overall temperature rise, radial heat homogenization control and the actual holding time under the condition of asynchronous heating of the inner and outer layers of alloy steel wire coils in spheroidizing annealing. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for compensating for temperature differences during spheroidizing annealing of alloy steel wire, comprising: S100: Obtain the representative temperatures of the inner and outer layers of the steel wire coil and the target spheroidizing annealing temperature range; calculate the radial temperature difference, compare the radial temperature difference of adjacent control cycles, and determine the temperature difference change state and radial thermal state. S200. Based on the radial thermal state, compare the inner and outer layer representative temperatures with the target spheroidizing annealing temperature range; when both the inner and outer layer representative temperatures are below this range, determine the overall heating requirement; when the outer layer representative temperature is within this range and the inner layer representative temperature is below this range, determine the radial heat equalization requirement. S300: Generate heating power control quantity and circulating air volume control quantity according to the overall heating demand or radial heat equalization demand; adjust the heating power when the overall temperature rises, and adjust the circulating air volume according to the temperature difference change state when the radial heat equalization is performed, with the current heating power as the upper limit; update the radial temperature difference after execution, and determine the temperature difference convergence state when the radial temperature difference does not increase. S400, the inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat homogenization threshold, which is determined as the heat homogenization condition; when the temperature difference convergence state and the heat homogenization condition maintain a continuous and stable cycle, the effective heat preservation starting point is determined; the compensation heat preservation time is determined according to the radial temperature difference of the effective heat preservation starting point, and the annealing completion state is generated when the heat homogenization condition is maintained after the time is reached.

[0006] Furthermore, the inner layer temperature is obtained by a temperature acquisition device located on the inner layer of the coil, and the outer layer temperature is obtained by a temperature acquisition device located on the outer layer of the coil; the temperature acquisition device uses a thermocouple or a resistance temperature detector and acquires the temperature according to the control cycle.

[0007] Furthermore, the radial temperature difference is the difference between the outer layer representative temperature and the inner layer representative temperature; when the radial temperature difference of the current control cycle is less than the radial temperature difference of the previous control cycle, the temperature difference change state is determined to be convergent; when the radial temperature difference of the current control cycle is greater than the radial temperature difference of the previous control cycle, the temperature difference change state is determined to be expanding; when the two are the same, the temperature difference change state is determined to be stable.

[0008] Furthermore, it also includes obtaining the current spheroidizing annealing stage, which includes a heating stage, a radial homogenization stage, and a holding stage; when the radial homogenization requirement is determined in the heating stage, it switches to the radial homogenization stage; and when the temperature difference convergence state and the homogenization conditions maintain the continuous stable cycle, it switches to the holding stage.

[0009] Furthermore, under the radial heat equalization requirement, the heating power control amount when the radial heat equalization requirement is determined is used as the power upper limit; the subsequent heating power control amount is not greater than the power upper limit, and the heating power control amount is reduced when the outer layer representative temperature reaches the outer layer temperature upper limit.

[0010] Furthermore, under the radial heat equalization requirement, the circulating air volume control amount is adjusted according to the temperature difference change state; when the temperature difference change state is expanding, the circulating air volume control amount is increased, and when the temperature difference change state is converging or stabilizing, the circulating air volume control amount is maintained.

[0011] Furthermore, after executing the heating power control amount and the circulating air volume control amount, the inner layer representative temperature and the outer layer representative temperature of the next control cycle are obtained and the radial temperature difference is updated; when the temperature difference convergence state is not established, the radial thermal state is regenerated according to the updated radial temperature difference, and the overall heating demand or radial heat equalization demand determination process of the next control cycle is entered.

[0012] Furthermore, the temperature difference convergence state and the heat equalization condition are detected according to the control cycle; after the temperature difference convergence state and the heat equalization condition maintain the continuous stable cycle, the starting time of the continuous stable cycle is determined as the effective heat preservation starting point.

[0013] Furthermore, the compensation insulation duration is determined based on the radial temperature difference and temperature difference convergence state corresponding to the effective insulation starting point; during the insulation stage, the radial temperature difference is updated according to the control cycle; when the maximum compensation insulation duration is reached and the heat homogenization condition is not maintained, an abnormal state is generated; when the compensation insulation duration is reached and the heat homogenization condition is maintained, an annealing completion state is generated.

[0014] The present invention also provides a temperature difference compensation system for spheroidizing annealing of alloy steel wire, comprising: The radial thermal state determination module is used to obtain the inner layer representative temperature, outer layer representative temperature and target spheroidizing annealing temperature range of the wire coil, calculate the radial temperature difference, compare the radial temperature difference between the current control cycle and the previous control cycle, determine the temperature difference change state and generate the radial thermal state. The compensation requirement determination module, connected to the radial thermal state determination module, is used to compare the inner layer representative temperature and the outer layer representative temperature with the target spheroidizing annealing temperature range based on the radial thermal state. When both the inner layer representative temperature and the outer layer representative temperature are lower than the target spheroidizing annealing temperature range, the overall heating requirement is determined. When the outer layer representative temperature is within the target spheroidizing annealing temperature range and the inner layer representative temperature is lower than the target spheroidizing annealing temperature range, the radial heat equalization requirement is determined. The temperature difference compensation control module is connected to the compensation demand determination module. It is used to generate heating power control quantity and circulating air volume control quantity based on the overall heating demand or radial heat equalization demand. Under the overall heating demand, it adjusts the heating power. Under the radial heat equalization demand, it adjusts the circulating air volume with the current heating power as the upper limit and according to the temperature difference change state. After execution, it updates the radial temperature difference and determines the temperature difference convergence state. The heat preservation state determination module, connected to the temperature difference compensation control module, is used to determine the heat preservation condition as the condition where the inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat preservation threshold. When the temperature difference convergence state and the heat preservation condition maintain a continuous and stable cycle, an effective heat preservation starting point is determined. The compensation heat preservation duration is determined based on the radial temperature difference of the effective heat preservation starting point. When the compensation heat preservation duration is reached and the heat preservation condition is maintained, an annealing completion state is generated.

[0015] The key innovations of this invention include: (1) The radial thermal state is characterized by the inner layer representative temperature, the outer layer representative temperature and the radial temperature difference change state of the same wire coil in a continuous control cycle. The two representative temperatures are compared with the target spheroidizing annealing temperature range respectively. When both the inner and outer layers are below the target spheroidizing annealing temperature range, the overall heating demand is formed. When the outer layer representative temperature enters the target spheroidizing annealing temperature range and the inner layer representative temperature is still below the range, the radial heating demand is switched to establish a correspondence between the coil temperature state and the subsequent control mode.

[0016] (2) Set different heating power and circulating air volume control relationships for overall heating demand and radial heat equalization demand. Adjust the heating power under overall heating demand and use the current heating power as the upper limit of power under radial heat equalization demand. Adjust the circulating air volume according to the expansion, stabilization or convergence state of radial temperature difference. After the control is executed, re-acquire the inner representative temperature and outer representative temperature of the next control cycle. Form a temperature difference convergence state through the updated radial temperature difference and participate in subsequent control.

[0017] (3) Establish a connection between the actual radial heat homogenization state of the coil and the spheroidizing annealing heat preservation time. When the inner layer representative temperature and the outer layer representative temperature are both within the target spheroidizing annealing temperature range, the radial temperature difference is not greater than the heat homogenization threshold, and a continuous and stable cycle is maintained, determine the effective heat preservation starting point. Determine the compensation heat preservation time based on the radial temperature difference corresponding to the effective heat preservation starting point, and continuously check the heat homogenization conditions to form an annealing completion state or an abnormal state during the heat preservation process.

[0018] The following are its main beneficial effects: (1) By simultaneously utilizing the actual temperature and radial temperature difference of the inner and outer layers of the coil, and switching the overall heating demand and radial heat equalization demand based on the positional relationship between the two radial regions relative to the target spheroidizing annealing temperature range, different working conditions such as insufficient overall temperature of the coil and the outer layer heating first and the inner layer thermal response lagging can be distinguished, thereby reducing the inconsistency between the control state and the actual thermal state of the coil when control is based solely on furnace temperature or a single temperature measurement location.

[0019] (2) When the outer layer represents the temperature has entered the target spheroidizing annealing temperature range while the inner layer is still below that range, the subsequent heating power is limited to continue to increase, and the circulating air volume is adjusted according to the radial temperature difference change state so that the overall heat input control and the coil radial heat exchange control correspond to different thermal states respectively. Combined with the radial temperature difference feedback of the next control cycle, the current compensation action can be continuously checked to see if the temperature difference converges, reducing the situation where the outer layer continues to heat up while the inner layer is still in a state of thermal response lag.

[0020] (3) By taking the inner and outer layers as the target spheroidizing annealing temperature range and the radial temperature difference as the heat homogenization condition as the effective heat preservation starting point, the heat preservation time corresponds to the actual radial heat homogenization state of the wire coil, rather than starting only when the furnace temperature reaches the set value or the preset process time; and then determining the compensation heat preservation time according to the radial temperature difference at the effective heat preservation starting point, the actual effective heat preservation time connection deviation caused by the asynchronous heating of the inner and outer layers can be reduced, and the temperature difference compensation process can be re-entered when the heat homogenization condition is interrupted. Attached Figure Description

[0021] Figure 1 A schematic flowchart illustrating a method for compensating for temperature differences during spheroidizing annealing of alloy steel wire, provided for an embodiment of this application; Figure 2 This is a structural block diagram of an alloy steel wire spheroidizing annealing temperature difference compensation system provided in an embodiment of this application. Detailed Implementation

[0022] Example 1: Refer to Figure 1 This is a schematic flowchart of a method for compensating for temperature differences during spheroidizing annealing of alloy steel wire provided in an embodiment of the present invention. The process may include at least steps S100-S400: S100: Obtain the representative temperatures of the inner and outer layers of the steel wire coil and the target spheroidizing annealing temperature range; calculate the radial temperature difference, compare the radial temperature difference of adjacent control cycles, and determine the temperature difference change state and radial thermal state. S200. Based on the radial thermal state, compare the inner and outer layer representative temperatures with the target spheroidizing annealing temperature range; when both the inner and outer layer representative temperatures are below this range, determine the overall heating requirement; when the outer layer representative temperature is within this range and the inner layer representative temperature is below this range, determine the radial heat equalization requirement. S300: Generate heating power control quantity and circulating air volume control quantity according to the overall heating demand or radial heat equalization demand; adjust the heating power when the overall temperature rises, and adjust the circulating air volume according to the temperature difference change state when the radial heat equalization is performed, with the current heating power as the upper limit; update the radial temperature difference after execution, and determine the temperature difference convergence state when the radial temperature difference does not increase. S400, the inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat homogenization threshold, which is determined as the heat homogenization condition; when the temperature difference convergence state and the heat homogenization condition maintain a continuous and stable cycle, the effective heat preservation starting point is determined; the compensation heat preservation time is determined according to the radial temperature difference of the effective heat preservation starting point, and the annealing completion state is generated when the heat homogenization condition is maintained after the time is reached.

[0023] S100: Obtain the representative temperatures of the inner and outer layers of the steel wire coil and the target spheroidizing annealing temperature range; calculate the radial temperature difference, compare the radial temperature difference between adjacent control cycles, and determine the temperature difference change state and radial thermal state. In one embodiment, the alloy steel wire is loaded into the spheroidizing annealing furnace in a coiled state. The spheroidizing annealing furnace is equipped with a heating device, a circulating fan, a temperature acquisition device, and an industrial controller. The temperature measurement signal of the temperature acquisition device is connected to the radial thermal state determination module in the industrial controller. Before the spheroidizing annealing process starts, the industrial controller reads the pre-configured target spheroidizing annealing temperature range and control cycle for this batch, and completes a reference sampling before entering continuous temperature difference compensation. The sampling result is used as the temperature data of the previous control cycle.

[0024] The inner layer temperature of the coil reflects the actual temperature state of the area near the inner diameter of the wire coil, while the outer layer temperature reflects the actual temperature state of the area near the outer diameter of the wire coil. In one embodiment, the temperature acquisition device uses a heat-resistant thermocouple. Before loading the furnace, the temperature measuring end corresponding to the inner layer temperature is placed in the gap between the wires in the inner layer of the coil, and the temperature measuring end corresponding to the outer layer temperature is placed at the outer layer temperature. The temperature measuring ends are connected to the industrial controller through high-temperature resistant leads. In another embodiment, a resistance temperature detector (RTD) is used to complete periodic sampling at the same location.

[0025] When multiple temperature acquisition points are arranged in the inner or outer layer of the coil, the industrial controller reads the temperature of each position according to the same control cycle and obtains the corresponding inner or outer representative temperature according to the preset representative temperature formation rule. The representative temperature formation rule remains unchanged within the same annealing batch to avoid changes in radial temperature difference caused by the switching of measurement points due to changes in the selection of measurement points in different control cycles.

[0026] The radial thermal state determination module reads the inner and outer representative temperatures in each control cycle, and uses the difference between the outer and inner representative temperatures as the radial temperature difference for the current control cycle, while retaining the radial temperature difference formed in the previous control cycle. When the radial temperature difference in the current control cycle is less than that in the previous control cycle, the temperature difference change state is determined to be convergence; when the radial temperature difference in the current control cycle is greater than that in the previous control cycle, it is determined to be expansion; and when the two are the same, it is determined to be stable.

[0027] The temperature difference change here reflects the change in radial temperature difference of the wire coil between adjacent control cycles, rather than the spatial temperature difference between temperature measurement points in the furnace cavity. Therefore, under the condition that the outer layer temperature continues to rise while the inner layer temperature rises more slowly, even if the current radial temperature difference has not yet exceeded the heat equalization threshold, as long as the radial temperature difference continues to increase in adjacent control cycles, the industrial controller will still use this state as an expanded state in the radial thermal state to participate in the identification of subsequent control requirements.

[0028] If the temperature acquisition device fails to return an effective temperature within a control cycle, or if the sampled value exceeds the effective measurement range of the temperature acquisition device, the radial temperature difference and temperature difference change status will not be updated in this control cycle. The industrial controller retains the radial thermal status confirmed in the previous control cycle and triggers resampling in the next control cycle. After continuous sampling returns to normal, the most recent effective radial temperature difference is used as the comparison benchmark to avoid invalid sampled values ​​directly changing the subsequent heating power and circulating air volume.

[0029] After the above processing is completed, the radial thermal state includes at least the radial temperature difference and its temperature difference change state in the current control cycle. The inner layer representative temperature and the outer layer representative temperature are retained in the industrial controller to correspond to the radial thermal state. S200 receives the radial thermal state and simultaneously calls the inner layer representative temperature, outer layer representative temperature and target spheroidizing annealing temperature range of the corresponding control cycle to distinguish whether the current coil is in the overall heating demand or the radial heat equalization demand.

[0030] S200. Based on the radial thermal state, compare the representative temperatures of the inner and outer layers with the target spheroidizing annealing temperature range; determine the overall heating requirement when both the representative temperatures of the inner and outer layers are below this range, and determine the radial heat homogenization requirement when the representative temperature of the outer layer is within this range and the representative temperature of the inner layer is below this range. After receiving the radial thermal state formed by S100, the compensation demand determination module first reads the lower and upper limits of the target spheroidizing annealing temperature range, and then checks the position of the inner layer representative temperature and the outer layer representative temperature relative to the temperature range. This comparison does not replace the coil temperature with the furnace ambient temperature, but keeps the two temperature states of the inner and outer layers of the coil independently participating in the demand identification, so that the state in which the outer layer reaches the process temperature first while the inner layer is still in the heating process can be identified separately.

[0031] When both the inner and outer representative temperatures are below the target spheroidizing annealing temperature range, neither of the two radial regions of the coil has reached the target temperature state. The compensation requirement determination module determines the current control requirement as the overall heating requirement. At this time, the radial temperature difference and temperature difference change state still participate in the control boundary of subsequent power and circulating air volume, but the current main control object is still the overall temperature of the coil. It will not enter the radial homogenization stage prematurely because of the radial temperature difference in a single control cycle.

[0032] As the outer layer enters the target spheroidizing annealing temperature range first due to the hot gas and heating environment inside the furnace, while the inner layer's representative temperature is still below the target spheroidizing annealing temperature range, the compensation demand determination module switches the current control demand from overall heating demand to radial homogenization demand. This switch indicates that the current control focus has shifted from increasing the overall heat input of the coil to handling the radial temperature difference between the inner and outer layers of the coil. Accordingly, S300 no longer uses the heating power adjustment method under the overall heating demand.

[0033] In one implementation, the industrial controller simultaneously reads the current spheroidizing annealing stage, which includes a heating stage, a radial homogenization stage, and a holding stage. When the radial homogenization requirement is first determined during the heating stage, the current spheroidizing annealing stage is switched to the radial homogenization stage. Thereafter, even if the inner layer representative temperature is still lower than the target spheroidizing annealing temperature range, the heating power will no longer be continuously increased according to the normal overall heating logic.

[0034] When both the inner and outer representative temperatures enter the target spheroidizing annealing temperature range, the compensation requirement determination module does not immediately switch the spheroidizing annealing process to the heat preservation stage. Instead, it retains the current radial temperature difference and temperature difference change state for S300 and S400 to continue to verify. Only after the temperature difference convergence state and the heat homogenization conditions maintain a continuous and stable cycle will the current spheroidizing annealing stage switch from the radial heat homogenization stage to the heat preservation stage.

[0035] During radial heat equalization, if the outer layer representative temperature reaches the pre-configured upper limit of the outer layer temperature, while the inner layer representative temperature is still below the target spheroidizing annealing temperature range, the industrial controller maintains the radial heat equalization requirement and provides the S300 with the status that the outer layer temperature has reached the power limit boundary. The upper limit of the outer layer temperature serves as the heating power adjustment boundary for subsequent control, preventing the heating power from continuing to increase according to the overall heating logic because the inner layer has not yet reached the target temperature.

[0036] The overall heating demand or radial heat equalization demand output by S200 is directly fed into S300. S300 no longer independently selects the control mode based on a single temperature value, but instead configures the heating power control quantity and the circulating air volume control quantity according to the already identified control demand. The temperature difference change state in the radial thermal state is synchronously fed into S300 to limit the adjustment direction of the circulating air volume under the radial heat equalization demand.

[0037] S300: Generate heating power control and circulating air volume control quantities based on the overall heating demand or radial heat equalization demand; adjust the heating power during overall heating, and adjust the circulating air volume according to the temperature difference change state with the current heating power as the upper limit during radial heat equalization; update the radial temperature difference after execution, and determine the temperature difference convergence state when the radial temperature difference does not increase: After receiving the overall heating demand or radial heat equalization demand determined by S200, the temperature difference compensation control module generates heating power control quantity and circulating air volume control quantity according to different control requirements. The heating power control quantity acts on the heating device of the spheroidizing annealing furnace, and the circulating air volume control quantity acts on the circulating fan. In the electrically heated spheroidizing annealing furnace, the heating power control quantity is sent to the power adjustment terminal of the heating device by the industrial controller, and the circulating air volume control quantity is sent to the frequency conversion control terminal of the circulating fan by the industrial controller. When other adjustable heating devices are used, the power input method of the corresponding heating device is followed.

[0038] Under the overall heating demand, the industrial controller adjusts the heating power control amount according to the relationship between the inner layer representative temperature, the outer layer representative temperature and the target spheroidizing annealing temperature range. When both the inner layer representative temperature and the outer layer representative temperature are lower than the target spheroidizing annealing temperature range, the heating power is allowed to be increased within the preset power control range. The circulating air volume maintains the current control amount or operates according to the circulating air volume of the heating stage pre-configured by the spheroidizing annealing furnace during this stage. When the radial temperature difference expands, the temperature difference change state of the next control cycle continues to participate in the control demand verification.

[0039] When switching from overall heating demand to radial heat homogenization demand, the temperature difference compensation control module records the heating power control amount being executed in this control cycle and uses this heating power control amount as the power upper limit. In subsequent control cycles of the radial heat homogenization stage, even if the inner layer representative temperature is still lower than the target spheroidizing annealing temperature range, the new heating power control amount will no longer exceed the power upper limit. When the outer layer representative temperature reaches the outer layer temperature upper limit, the heating power control amount will be reduced below the power upper limit.

[0040] The aforementioned power limit and circulating air volume adjustment adopt different control bases. Under radial heat equalization demand, the temperature difference compensation control module reads the temperature difference change state formed by S100. When the temperature difference change state is expanding, the circulating air volume control amount is increased. When the temperature difference change state is converging or stabilizing, the current circulating air volume control amount is maintained, so that the gas circulation conditions of the current control cycle correspond to the development direction of the radial temperature difference.

[0041] In one implementation, the circulating air volume control parameter uses the operating frequency of the circulating fan as the execution parameter. The industrial controller changes the operating frequency of the circulating fan corresponding to adjacent control cycles according to a preset adjustment step size and limits it within the range of circulating air volume. In another implementation, the circulating air volume control parameter uses the circulating fan speed or the actual circulating air volume as the execution parameter. All implementations maintain the control relationship of "increasing the circulating air volume when the radial temperature difference expands and maintaining the circulating air volume when the radial temperature difference converges or stabilizes".

[0042] After the heating device and circulating fan complete one control cycle, the temperature acquisition device rereads the inner and outer representative temperatures for the next control cycle. The temperature difference compensation control module updates the radial temperature difference according to the same calculation relationship as S100. The updated radial temperature difference is compared with the radial temperature difference before execution. If the updated radial temperature difference is not greater than the radial temperature difference before execution, the temperature difference convergence state is determined. If the updated radial temperature difference is greater than the radial temperature difference before execution, the temperature difference convergence state is determined to be invalid, and the radial thermal state formation process of the next control cycle begins.

[0043] When the temperature difference convergence state is not established after the circulating air volume adjustment, the industrial controller does not regard the first control action as the end of radial heat equalization. Instead, it uses the updated radial temperature difference as the new current control cycle radial temperature difference to regenerate the radial heat state. The regenerated radial heat state re-enters S200. When the outer layer representative temperature is still within the target spheroidizing annealing temperature range and the inner layer representative temperature is still below the target spheroidizing annealing temperature range, the radial heat equalization requirement continues to be maintained, and S300 performs power limiting and circulating air volume adjustment for the next control cycle.

[0044] If the circulating air volume control has reached the pre-configured circulating air volume range boundary, and the radial temperature difference continues to expand during the continuous control cycle, the industrial controller will not continue to increase the circulating air volume control, but will maintain the current allowable control and generate an abnormal state; it will not enter the normal heat preservation end process before the abnormal state is cleared, so as to avoid directly taking the radial temperature difference that cannot converge as expected as the heat homogenization completion state.

[0045] Once the inner layer representative temperature enters the target spheroidizing annealing temperature range during the radial homogenization process, the execution results of heating power and circulating air volume are still checked by temperature sampling in the next control cycle. At this time, the temperature difference convergence state formed in S300, along with the updated inner layer representative temperature, outer layer representative temperature, and radial temperature difference, enters S400. The insulation status determination module checks whether the coil has reached the initial conditions for effective insulation.

[0046] S400: The inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range, and the radial temperature difference is not greater than the homogenization threshold, are determined as homogenization conditions. When the temperature difference convergence state and the homogenization conditions maintain a continuous and stable cycle, an effective heat preservation starting point is determined. The compensation heat preservation duration is determined based on the radial temperature difference of the effective heat preservation starting point. When this duration is reached and the homogenization conditions are maintained, an annealing completion state is generated. After receiving the temperature difference convergence status generated by S300 and the inner layer representative temperature, outer layer representative temperature and radial temperature difference of the current control cycle, the heat preservation status determination module checks whether the two representative temperatures are within the target spheroidizing annealing temperature range and compares the radial temperature difference with the heat homogenization threshold. The heat homogenization condition is composed of both the inner layer representative temperature and the outer layer representative temperature being within the target spheroidizing annealing temperature range and the radial temperature difference not being greater than the heat homogenization threshold. If any condition is not met, the effective heat preservation timer will not be started.

[0047] The heat absorption threshold and continuous stabilization period are read by the industrial controller before the start of this batch of spheroidizing annealing, and their values ​​correspond to the spheroidizing annealing process parameters used. The continuous stabilization period is based on the control cycle. When the temperature difference convergence state and the heat absorption condition are both continuously met in adjacent control cycles, the continuous stabilization state is interrupted and the radial heat state is re-entered for verification. If the temperature difference convergence state is not met, the inner layer representative temperature is lower than the target spheroidizing annealing temperature range, the outer layer representative temperature exceeds the target spheroidizing annealing temperature range, or the radial temperature difference is greater than the heat absorption threshold in any control cycle, the continuous stabilization state is interrupted and the radial heat state is re-entered for verification.

[0048] When the temperature difference convergence state and the heat homogenization condition are maintained continuously until the end of the continuous stable cycle, the heat preservation state determination module backtracks to the control cycle in which the temperature difference convergence state and the heat homogenization condition first simultaneously occur, and determines the start time of the control cycle as the effective heat preservation start point; the effective heat preservation start point is independent of the time when the spheroidizing annealing furnace program enters the heat preservation stage in advance, and the actual heat preservation time is established based on the time when the temperature difference convergence state and the heat homogenization condition first simultaneously occur.

[0049] After determining the effective insulation starting point, the insulation state determination module reads the radial temperature difference corresponding to the starting point as the input for the compensation insulation duration, and selects the corresponding compensation insulation duration based on the temperature difference convergence state before entering the effective insulation starting point. In one embodiment, the industrial controller pre-configures the correspondence between the radial temperature difference range, the temperature difference convergence state and the compensation insulation duration. First, it obtains the basic insulation duration according to the radial temperature difference range corresponding to the effective insulation starting point, and then selects the corresponding duration configuration according to the temperature difference convergence state.

[0050] The compensation insulation duration does not replace the insulation control requirements of the spheroidizing annealing process itself, but is used as the insulation control parameter corresponding to this radial temperature difference compensation after the effective insulation starting point is established. During the insulation stage, the temperature acquisition device still acquires the inner layer representative temperature and the outer layer representative temperature according to the same control cycle, and the industrial controller continues to update the radial temperature difference so that the heat homogenization condition remains under monitoring throughout the compensation insulation process.

[0051] When the radial temperature difference exceeds the heat homogenization threshold again during a certain control cycle in the heat preservation stage, or when either the inner layer representative temperature or the outer layer representative temperature deviates from the target spheroidizing annealing temperature range, the heat preservation state determination module records the heat homogenization condition as not maintained and re-sends the current radial temperature difference to the radial heat state determination module; then, according to the control relationship from S100 to S300, the overall heating requirement or radial heat homogenization requirement is rechecked until the heat homogenization condition is met again, and no annealing completion state is generated during the abnormal period.

[0052] When the compensation holding time is reached, the holding status determination module checks the inner layer representative temperature, outer layer representative temperature and radial temperature difference of the most recent control cycle. If the heat equalization conditions are still maintained, the annealing completion state is generated. After the annealing completion state is generated, the industrial controller ends the current compensation holding time and switches the spheroidizing annealing furnace to the equipment state corresponding to the subsequent process, and no longer increases the circulating air volume according to the radial heat equalization requirements.

[0053] In one implementation, a maximum compensation insulation time is set. When the effective insulation process reaches the maximum compensation insulation time but the heat homogenization condition is still not maintained, the insulation state determination module generates an abnormal state instead of generating an annealing completion state. In this abnormal state, the industrial controller maintains the currently allowed temperature control boundary and waits for the temperature to meet the heat homogenization condition again or enters the pre-configured abnormal handling process to avoid directly replacing the actual heat homogenization status verification of the coil with the time limit being reached.

[0054] Therefore, the radial thermal state formed in S100 is transformed into the overall heating demand or radial heat equalization demand in S200. S300 forms the actual control of heating power and circulating air volume based on the demand and checks the control results with the radial temperature difference in the next control cycle. S400 then determines the effective heat preservation starting point and the compensation heat preservation duration based on the actual temperature state of the coil after compensation. When the heat equalization condition is interrupted during the heat preservation stage, it returns to the radial thermal state processing, so that the same wire coil continues to operate along a unified temperature acquisition and control cycle during the heating, radial heat equalization and heat preservation processes.

[0055] Example 2: Figure 2 A structural block diagram of a temperature difference compensation system for spheroidizing annealing of alloy steel wire according to an embodiment of the present invention is shown. Figure 2 As shown, the structure may include: The radial thermal state determination module 01 is used to acquire the inner layer representative temperature, outer layer representative temperature, and target spheroidizing annealing temperature range of the wire coil, calculate the radial temperature difference, compare the radial temperature difference between the current control cycle and the previous control cycle, determine the temperature difference change state, and generate the radial thermal state. During system operation, the radial thermal state determination module receives the inner layer temperature and outer layer temperature of the coil collected by the temperature acquisition device according to the control cycle. The inner layer representative temperature corresponds to the temperature state of the coil near the inner diameter region, and the outer layer representative temperature corresponds to the temperature state of the coil near the outer diameter region. The target spheroidizing annealing temperature range is read by the industrial controller when the current spheroidizing annealing process is started and maintains the corresponding relationship during the current control process. After each control cycle is completed, the radial thermal state determination module calculates the difference between the outer layer representative temperature and the inner layer representative temperature to form the radial temperature difference of the current control cycle, and reads the radial temperature difference retained in the previous control cycle as the comparison object. When the radial temperature difference in the current control cycle is less than that in the previous control cycle, the temperature difference change state is determined to be convergent; when the radial temperature difference in the current control cycle is greater than that in the previous control cycle, the temperature difference change state is determined to be expanding; when the two are the same, the temperature difference change state is determined to be stable. The current radial temperature difference and the corresponding temperature difference change state together constitute the radial thermal state, which is transmitted to the compensation requirement determination module by the radial thermal state determination module.

[0056] When the temperature acquisition device fails to return the inner or outer representative temperature in the current control cycle, the radial thermal state determination module does not use the missing temperature to calculate the new radial temperature difference. Instead, it retains the radial thermal state confirmed in the previous control cycle and marks the current control cycle as an abnormal temperature acquisition. After temperature acquisition resumes, the radial temperature difference of the most recent effective control cycle is used as a comparison benchmark to re-determine the temperature difference change state, avoiding the direct change in the identification results of subsequent overall heating demand and radial heat equalization demand due to acquisition interruption. For implementations where multiple inner or outer temperature acquisition positions are set for the same wire coil, each position is sampled synchronously in the same control cycle, and the inner and outer representative temperatures are obtained according to the pre-configured representative temperature formation rules that remain unchanged during this spheroidizing annealing process. The radial thermal state thus formed always corresponds to the same wire coil and the same control cycle.

[0057] The compensation demand determination module 02, connected to the radial thermal state determination module, is used to compare the inner layer representative temperature and the outer layer representative temperature with the target spheroidizing annealing temperature range based on the radial thermal state. When both the inner layer representative temperature and the outer layer representative temperature are lower than the target spheroidizing annealing temperature range, the overall heating demand is determined. When the outer layer representative temperature is within the target spheroidizing annealing temperature range and the inner layer representative temperature is lower than the target spheroidizing annealing temperature range, the radial homogenization demand is determined. After receiving the radial thermal state, the compensation demand determination module calls the inner layer representative temperature and the outer layer representative temperature belonging to the same control cycle as the radial thermal state, and checks the position of the two representative temperatures relative to the target spheroidizing annealing temperature range, without using a single furnace temperature to replace the radial temperature state of the coil itself. When both representative temperatures are lower than the target spheroidizing annealing temperature range, the current coil is still in an overall heating state, and the compensation demand determination module forms the overall heating demand and sends it to the temperature difference compensation control module. When the outer layer representative temperature first enters the target spheroidizing annealing temperature range while the inner layer representative temperature is still below that range, the compensation demand determination module switches the current control demand to radial heat homogenization demand and provides the temperature difference compensation control module with the temperature difference change state formed in S100 and the radial heat homogenization demand together; at this time, subsequent control no longer continuously increases the heating power based solely on the fact that the inner layer temperature has not reached the target range.

[0058] In one implementation, the industrial controller simultaneously stores the current spheroidizing annealing stage, which operates according to a heating stage, a radial homogenization stage, and a holding stage. When radial homogenization demand is first generated during the heating stage, the current spheroidizing annealing stage is switched to the radial homogenization stage. After both the inner and outer representative temperatures enter the target spheroidizing annealing temperature range, the compensation demand determination module retains the current radial temperature difference for subsequent homogenization condition verification. Before the temperature difference convergence state and the homogenization conditions have maintained a continuous stable cycle, the module does not directly switch to the holding stage. If the temperature acquisition result of the current cycle contains a temperature acquisition anomaly marker, the compensation demand determination module maintains the overall heating demand or radial homogenization demand determined in the previous effective control cycle and does not re-switch the control demand based on the abnormal sampling result. After the next effective control cycle arrives, the temperature range comparison is re-executed based on the newly formed radial thermal state.

[0059] The temperature difference compensation control module 03, connected to the compensation demand determination module, is used to generate heating power control and circulating air volume control based on the overall heating demand or radial heat equalization demand. Under the overall heating demand, the heating power is adjusted; under the radial heat equalization demand, the current heating power is used as the upper limit, and the circulating air volume is adjusted according to the temperature difference change state. After execution, the radial temperature difference is updated, and the temperature difference convergence state is determined. The temperature difference compensation control module sends the heating power control to the power adjustment terminal of the heating device and the circulating air volume control to the control terminal of the circulating fan. Under the overall heating demand, the heating power is adjusted according to the difference between the representative temperature of the inner and outer layers of the coil and the target spheroidizing annealing temperature range. The circulating air volume operates according to the control amount of the current heating stage. During the control cycle switching from the overall heating demand to the radial heat equalization demand, the temperature difference compensation control module reads the heating power currently being executed and determines this heating power as the upper limit of the power for the subsequent radial heat equalization stage. After entering the radial heat equalization stage, the new heating power control amount does not exceed the power upper limit. When the temperature difference changes, the circulating air volume control amount is increased. When the temperature difference changes, the current circulating air volume control amount is maintained. When the outer layer representative temperature reaches the outer layer temperature upper limit, the temperature difference compensation control module reduces the heating power control amount within the power upper limit range.

[0060] After the heating device and circulating fan complete the execution of the current control cycle, the radial thermal state determination module re-obtains the inner and outer representative temperatures in the next control cycle and returns the updated radial temperature difference to the temperature difference compensation control module. The temperature difference compensation control module compares the updated radial temperature difference with the radial temperature difference before control execution. If the updated radial temperature difference is not greater than the radial temperature difference before control execution, the temperature difference convergence state is determined. If the updated radial temperature difference is greater than the radial temperature difference before control execution, the temperature difference convergence state is determined to be invalid, and the update result is sent to the radial thermal state processing of the next control cycle. If the circulating fan does not return to the effective execution state or the circulating air volume control amount has reached the preset circulating air volume range boundary while the radial temperature difference continues to expand, the temperature difference compensation control module maintains the current allowable control amount and forms an abnormality mark, and no longer increases the circulating air volume control amount. This abnormality mark and the latest radial temperature difference are retained to the next control cycle. The heat preservation state determination module does not generate an annealing completion state until the abnormal state is resolved.

[0061] The heat preservation state determination module 04 is connected to the temperature difference compensation control module. It is used to determine the heat preservation condition as when the inner layer representative temperature and the outer layer representative temperature are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat preservation threshold. When the temperature difference convergence state and the heat preservation condition maintain a continuous and stable cycle, an effective heat preservation starting point is determined. The compensation heat preservation duration is determined according to the radial temperature difference corresponding to the effective heat preservation starting point. When the compensation heat preservation duration is reached and the heat preservation condition is maintained, an annealing completion state is generated.

[0062] The insulation state determination module receives the temperature difference convergence state and the latest radial temperature difference generated by the temperature difference compensation control module, and reads the inner layer representative temperature and outer layer representative temperature corresponding to the same control cycle. When the temperature difference convergence state and the heat equalization condition are both met in the current control cycle, the current control cycle is recorded as a continuous stable cycle. If either state is not met, the current continuous stable state is interrupted.

[0063] When the temperature difference convergence state and the heat equalization condition are maintained until the end of a continuous stable cycle, the heat preservation state determination module determines the start time of the control cycle when the temperature difference convergence state and the heat equalization condition are first established simultaneously as the effective heat preservation start point; and reads the radial temperature difference corresponding to the effective heat preservation start point as the basis for determining the compensation heat preservation time.

[0064] In one implementation, the industrial controller pre-configures the correspondence between radial temperature difference and compensation holding time. The holding state determination module obtains the corresponding compensation holding time according to the radial temperature difference range corresponding to the effective holding start point. After entering the holding stage, it continues to receive updated inner layer representative temperature, outer layer representative temperature, and radial temperature difference according to the same control cycle. When the compensation holding time is reached, the heat homogenization condition is checked again. If the heat homogenization condition is maintained, an annealing completion state is generated. If the radial temperature difference exceeds the heat homogenization threshold again during the holding process, or if either the inner layer representative temperature or the outer layer representative temperature leaves the target spheroidizing annealing temperature range, the holding state determination module does not generate an annealing completion state and feeds back the latest radial temperature difference to the radial heat state determination module to re-enter the radial heat state, compensation requirements, and temperature difference compensation control process. If the maximum compensation holding time is reached but the heat homogenization condition is still not maintained, an abnormal state is generated. The system maintains the current allowed temperature control state and waits for subsequent effective control cycles to re-check.

Claims

1. A method for compensating for temperature difference during spheroidizing annealing of alloy steel wire, characterized in that, include: S100: Obtain the representative temperatures of the inner and outer layers of the steel wire coil and the target spheroidizing annealing temperature range; Calculate the radial temperature difference, compare the radial temperature difference between adjacent control cycles, and determine the temperature difference change state and radial thermal state; S200. Based on the radial thermal state, compare the inner and outer layer representative temperatures with the target spheroidizing annealing temperature range; when both the inner and outer layer representative temperatures are below this range, determine the overall heating requirement; when the outer layer representative temperature is within this range and the inner layer representative temperature is below this range, determine the radial heat equalization requirement. S300: Generate heating power control quantity and circulating air volume control quantity according to the overall heating demand or radial heat equalization demand; adjust the heating power when the overall temperature rises, and adjust the circulating air volume according to the temperature difference change state when the radial heat equalization is performed, with the current heating power as the upper limit; update the radial temperature difference after execution, and determine the temperature difference convergence state when the radial temperature difference does not increase. S400, the inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat homogenization threshold, which is determined as the heat homogenization condition; when the temperature difference convergence state and the heat homogenization condition maintain a continuous and stable cycle, the effective heat preservation starting point is determined. The compensation insulation duration is determined based on the radial temperature difference at the effective insulation starting point. When the insulation duration is reached and the uniform heating conditions are maintained, the annealing completion state is generated.

2. The method according to claim 1, characterized in that, The inner layer temperature is obtained by a temperature acquisition device located on the inner layer of the coil, and the outer layer temperature is obtained by a temperature acquisition device located on the outer layer of the coil; the temperature acquisition device uses a thermocouple or a resistance temperature detector and acquires the temperature according to the control cycle.

3. The method according to claim 1, characterized in that, The radial temperature difference is the difference between the outer layer representative temperature and the inner layer representative temperature. When the radial temperature difference of the current control cycle is less than that of the previous control cycle, the temperature difference change state is determined to be convergent. When the radial temperature difference of the current control cycle is greater than that of the previous control cycle, the temperature difference change state is determined to be expanding. When the two are the same, the temperature difference change state is determined to be stable.

4. The method according to claim 1, characterized in that, It also includes obtaining the current spheroidizing annealing stage, which includes a heating stage, a radial homogenization stage, and a holding stage; when the radial homogenization requirement is determined in the heating stage, switching to the radial homogenization stage; and when the temperature difference convergence state and the homogenization conditions maintain the continuous stable cycle, switching to the holding stage.

5. The method according to claim 1, characterized in that, Under the radial heat equalization requirement, the heating power control amount at which the radial heat equalization requirement is determined is used as the upper limit of the power; the subsequent heating power control amount is not greater than the upper limit of the power, and the heating power control amount is reduced when the outer layer representative temperature reaches the upper limit of the outer layer temperature.

6. The method according to claim 1, characterized in that, Under the radial heat equalization requirement, the circulating air volume control amount is adjusted according to the temperature difference change state; when the temperature difference change state is expanding, the circulating air volume control amount is increased, and when the temperature difference change state is converging or stabilizing, the circulating air volume control amount is maintained.

7. The method according to claim 1, characterized in that, After executing the heating power control and circulating air volume control, the inner representative temperature and outer representative temperature of the next control cycle are obtained and the radial temperature difference is updated. If the temperature difference convergence state is not established, the radial thermal state is regenerated based on the updated radial temperature difference, and the process of determining the overall heating demand or radial heat equalization demand of the next control cycle is entered.

8. The method according to claim 1, characterized in that, The temperature difference convergence state and the heat equalization condition are detected according to the control cycle; after the temperature difference convergence state and the heat equalization condition maintain the continuous stable cycle, the starting time of the continuous stable cycle is determined as the effective heat preservation starting point.

9. The method according to claim 1, characterized in that, The compensation insulation duration is determined based on the radial temperature difference and temperature difference convergence state corresponding to the effective insulation starting point. During the heat preservation stage, the radial temperature difference is updated according to the control cycle. When the maximum compensation heat preservation time is reached and the heat homogenization condition is not maintained, an abnormal state is generated. When the compensation heat preservation time is reached and the heat homogenization condition is maintained, an annealing completion state is generated.

10. A temperature difference compensation system for spheroidizing annealing of alloy steel wire, applied to the method described in any one of claims 1 to 9, characterized in that, include: The radial thermal state determination module is used to obtain the inner layer representative temperature, outer layer representative temperature and target spheroidizing annealing temperature range of the wire coil, calculate the radial temperature difference, compare the radial temperature difference between the current control cycle and the previous control cycle, determine the temperature difference change state and generate the radial thermal state. The compensation requirement determination module, connected to the radial thermal state determination module, is used to compare the inner layer representative temperature and the outer layer representative temperature with the target spheroidizing annealing temperature range based on the radial thermal state. When both the inner layer representative temperature and the outer layer representative temperature are lower than the target spheroidizing annealing temperature range, the overall heating requirement is determined. When the outer layer representative temperature is within the target spheroidizing annealing temperature range and the inner layer representative temperature is lower than the target spheroidizing annealing temperature range, the radial heat equalization requirement is determined. The temperature difference compensation control module is connected to the compensation demand determination module. It is used to generate heating power control quantity and circulating air volume control quantity based on the overall heating demand or radial heat equalization demand. Under the overall heating demand, it adjusts the heating power. Under the radial heat equalization demand, it adjusts the circulating air volume with the current heating power as the upper limit and according to the temperature difference change state. After execution, it updates the radial temperature difference and determines the temperature difference convergence state. The heat preservation state determination module, connected to the temperature difference compensation control module, is used to determine the heat preservation condition as the condition where the inner and outer layer representative temperatures are both within the target spheroidizing annealing temperature range and the radial temperature difference is not greater than the heat preservation threshold. When the temperature difference convergence state and the heat preservation condition maintain a continuous and stable cycle, an effective heat preservation starting point is determined. The compensation heat preservation duration is determined based on the radial temperature difference of the effective heat preservation starting point. When the compensation heat preservation duration is reached and the heat preservation condition is maintained, an annealing completion state is generated.

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