A method for reducing the surface hardness of 40Mn2 steel

Abstract

The application relates to the technical field of 40Mn2 steel processing, in particular to a method for reducing the surface hardness of 40Mn2 steel. The method comprises the following steps: establishing a cycle correction period according to the parameters of a round steel to be processed; generating a plurality of feedback time nodes according to the cycle correction period, and obtaining a processing evaluation value of a previous cycle correction period according to the feedback time nodes; generating a correction instruction according to the processing evaluation value, and correcting the processing parameters in a next cycle correction period according to the correction instruction. The processing process of the 40Mn2 round steel is dynamically corrected by establishing the cycle correction period, the surface hardness of the 40Mn2 round steel is reduced by reducing the finish rolling temperature, the center hardness and the surface hardness of the processed 40Mn2 round steel are more uniform, so that subsequent sawing is facilitated, and thermal wear is reduced. The surface hardness of the 40Mn2 round steel is reduced by prolonging the pit entry cooling duration, so that the center hardness and the surface hardness of the processed 40Mn2 round steel are more uniform.

Description

Technical Field

[0001] This application relates to the field of 40Mn2 steel processing technology, and in particular to a method for reducing the surface hardness of 40Mn2 steel. Background Technology

[0002] 40Mn2 steel is widely used in the manufacture of parts that operate under heavy loads, such as shafts, crankshafts, axles, piston rods, worm gears, levers, connecting rods, bolts, screws, reinforcing rings, springs, and other quenched and tempered parts. 40Mn2 steel is a medium-carbon manganese steel with high strength, plasticity, and wear resistance, as well as good machinability and heat treatment performance.

[0003] However, the current production process of 40Mn2 steel suffers from insufficient slow cooling time, resulting in the presence of Widmanstätten and bainitic hard phases in the core. This causes the cross-sectional hardness to fluctuate by ΔHV > 94, resulting in uneven hardness of the 40Mn2 steel and low surface hardness. Consequently, the cut surface is rough and thermal wear is severe during sawing. Summary of the Invention

[0004] The purpose of this application is to provide a method for reducing the surface hardness of 40Mn2 steel in order to solve the above-mentioned technical problems.

[0005] In some embodiments of this application, the processing of 40Mn2 round steel is dynamically corrected by establishing a cyclic correction cycle. By reducing the final rolling temperature, the surface hardness of the 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform, thereby facilitating subsequent sawing and reducing thermal wear.

[0006] In some embodiments of this application, the surface hardness of 40Mn2 round steel is reduced by extending the cooling time in the pit, so that the center hardness and surface hardness of the processed 40Mn2 round steel are more uniform. At the same time, the cooling time in the pit is dynamically adjusted by cyclic correction, so as to improve work efficiency while ensuring processing quality and achieve efficient processing of 40Mn2 round steel.

[0007] In some embodiments of this application, a method for reducing the surface hardness of 40Mn2 steel is provided, including:

[0008] Establish a cyclic correction cycle based on the parameters of the round steel to be processed;

[0009] Multiple feedback time nodes are generated based on the cyclic correction cycle, and the processing evaluation value of the previous cyclic correction cycle is obtained based on the feedback time nodes.

[0010] A correction instruction is generated based on the processing evaluation value, and the processing parameters in the next correction cycle are corrected based on the correction instruction.

[0011] In some embodiments of this application, when establishing a cyclic correction cycle based on the parameters of the round steel to be processed, the following are included:

[0012] Obtain the quantity and diameter of the round steel bars to be processed;

[0013] A first demand evaluation value A1 is generated based on the quantity of round steel to be processed;

[0014] A second demand evaluation value A2 is generated based on the diameter of the round steel to be processed;

[0015] A demand evaluation value a is generated based on the first demand evaluation value A1 and the second demand evaluation value A2;

[0016] a=n1 A1+n2 A2, where n1 is the preset first weight coefficient and n2 is the second weight coefficient;

[0017] The single processing quantity and total processing time are set according to the demand evaluation value a;

[0018] The time interval for a single cycle correction is set based on the total processing time of a single operation.

[0019] In some embodiments of this application, obtaining the hardness evaluation value of the processed round steel from the previous correction cycle includes:

[0020] The number of round steel bars to be sampled is set according to the single processing volume in the previous correction cycle.

[0021] Generate hardness evaluation values ​​for each sampled round steel bar;

[0022] Establish an initial sequence C of hardness evaluation values ​​within the previous correction cycle, C=(c1,c2…c…). m ), where m is the number of sampled round steel bars, and ci is the hardness evaluation value of the i-th sampled round steel bar;

[0023] The initial sequence C of hardness evaluation values ​​is preprocessed to generate a sequence C1, C1=(c1,c2…c m-m1 ), where m1 is the number of hardness evaluation values ​​to be removed;

[0024] The processing evaluation value compensation coefficient e is generated based on m1;

[0025] Based on the hardness evaluation value sequence C1 and the number of processing evaluation value compensations e, the processing evaluation value d of the previous correction cycle is generated;

[0026] d=e ( ) / (m-m1).

[0027] In some embodiments of this application, when generating correction instructions based on processing evaluation values, the following are included:

[0028] Preset the first processing evaluation value threshold and the second processing evaluation value threshold;

[0029] When the processing evaluation value d is less than the preset first processing evaluation value threshold, a final rolling temperature correction command is generated, and a final rolling temperature correction coefficient p1 is generated according to the final rolling temperature correction command.

[0030] Obtain the processing parameters from the previous correction cycle, and generate the preset final rolling temperature v1 and the final rolling temperature fluctuation evaluation value z based on the processing parameters;

[0031] The final rolling temperature compensation coefficient p2 is set based on the final rolling temperature fluctuation evaluation value z.

[0032] The final rolling temperature v, v=p1, is generated for the next cycle correction. p2 v1.

[0033] In some embodiments of this application, generating the final rolling temperature fluctuation evaluation value z includes:

[0034] Multiple temperature monitoring nodes are set according to the processing parameters;

[0035] Generate the final rolling temperature at each temperature monitoring time point, and generate the temperature difference value at each temperature monitoring time point based on the preset final rolling steel temperature v1.

[0036] The final rolling temperature fluctuation evaluation value z is set based on all the temperature differences mentioned.

[0037] In some embodiments of this application, when generating correction instructions based on processing evaluation values, the method further includes:

[0038] When the processing evaluation value d is less than the preset first processing evaluation value threshold, a first-level slow cooling time correction instruction is generated.

[0039] The first slow cooling time correction coefficient p2 is set according to the first-level slow cooling time correction command;

[0040] Obtain the slow cooling duration t1 of the previous correction cycle;

[0041] Based on the first slow cooling duration correction coefficient p2 and the slow cooling duration t1, the slow cooling duration t of the next cycle correction period is set, where t = p2. t1.

[0042] In some embodiments of this application, when generating correction instructions based on processing evaluation values, the method further includes:

[0043] When the processing evaluation value d is between the preset first processing evaluation value threshold and the preset second processing evaluation value threshold, no correction instruction is generated;

[0044] When the processing evaluation value d is greater than the preset second processing evaluation value threshold, a secondary slow cooling time correction command is generated;

[0045] The second slow cooling time correction coefficient p3 is set according to the secondary slow cooling time correction command;

[0046] Obtain the slow cooling duration t1 of the previous correction cycle;

[0047] Based on the second slow cooling duration correction coefficient p3 and the slow cooling duration t1, the slow cooling duration t of the next correction cycle is set, where t = p3. t1.

[0048] In some embodiments of this application, when generating the processing evaluation value compensation coefficient e based on m1, the following are included:

[0049] Establish the first quantity interval (M1, M2), the second quantity interval (M2, M3), and the third quantity interval (M3, M4).

[0050] If the number of discarded hardness evaluation values ​​m1 falls within the first quantity range, the compensation coefficient e is set to the preset first compensation coefficient e1; if the number of discarded hardness evaluation values ​​m1 falls within the second quantity range, the compensation coefficient e is set to the preset second compensation coefficient e2; if the number of discarded hardness evaluation values ​​m1 falls within the third quantity range, the compensation coefficient e is set to the preset third compensation coefficient e3, and e3 <e2<e1<1。

[0051] In some embodiments of this application, the generation of hardness evaluation values ​​for each sampled round steel bar includes:

[0052] Select a single sample round steel bar

[0053] Multiple hardness test points are set according to the diameter of the sampled round steel.

[0054] Obtain the hardness values ​​of each hardness test point and establish a hardness value sequence F, F=(f1,f2…fg), where g is the number of hardness test points and fi is the hardness value of the i-th test point;

[0055] Generate the average hardness Δf1, the difference hardness Δf2, and the hardness variance k based on the hardness value sequence F;

[0056] An average hardness evaluation value H1 is generated based on the average hardness Δf1.

[0057] A difference hardness evaluation value H2 is generated based on the difference hardness Δf2;

[0058] A hardness evaluation value compensation coefficient b is generated based on the hardness variance k.

[0059] Generate a hardness evaluation value c, c = b(n3) H1+n4 H2), where n3 is the preset third weight coefficient and n4 is the preset fourth weight coefficient.

[0060] In some embodiments of this application, when generating the hardness evaluation value compensation coefficient b based on the hardness variance k, the following steps are included:

[0061] The first hardness variance interval (K1, K2), the second hardness variance interval (K2, K3), and the third hardness variance interval (K3, K4) are preset.

[0062] If the hardness variance falls within the first hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset first hardness evaluation value compensation coefficient b1; if the hardness variance falls within the second hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset second hardness evaluation value compensation coefficient b2; if the hardness variance falls within the third hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset third hardness evaluation value compensation coefficient b3, and b3 <b2<b1<1。

[0063] Compared with the prior art, the method for reducing the surface hardness of 40Mn2 steel according to the embodiments of this application has the following advantages:

[0064] By establishing a cyclic correction cycle, the processing of 40Mn2 round steel is dynamically corrected. By reducing the final rolling temperature, the surface hardness of 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform, thus facilitating subsequent sawing and reducing thermal wear.

[0065] By extending the cooling time in the pit, the surface hardness of 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform. At the same time, by dynamically adjusting the cooling time in the pit through cyclic correction, the work efficiency is improved while ensuring processing quality, thus achieving efficient processing of 40Mn2 round steel. Attached Figure Description

[0066] Figure 1 This is a flowchart illustrating a method for reducing the surface hardness of 40Mn2 steel in a preferred embodiment of this application. Detailed Implementation

[0067] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0068] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0069] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0070] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0071] like Figure 1 As shown, a preferred embodiment of this application describes a method for reducing the surface hardness of 40Mn2 steel, comprising:

[0072] S1O1: Establish a cyclic correction period based on the parameters of the round steel to be processed;

[0073] S102: Generate multiple feedback time nodes based on the cyclic correction cycle, and obtain the processing evaluation value of the previous cyclic correction cycle based on the feedback time nodes;

[0074] S103: Generate correction instructions based on the processing evaluation value, and correct the processing parameters in the next correction cycle based on the correction instructions.

[0075] Specifically, when establishing a cyclic correction cycle based on the parameters of the round steel to be processed, it includes:

[0076] Obtain the quantity and diameter of the round steel bars to be processed;

[0077] A first demand evaluation value A1 is generated based on the quantity of round steel to be processed;

[0078] A second demand evaluation value A2 is generated based on the diameter of the round steel to be processed;

[0079] Demand evaluation value a is generated based on the first demand evaluation value A1 and the second demand evaluation value A2;

[0080] a=n1 A1+n2 A2, where n1 is the preset first weight coefficient and n2 is the second weight coefficient;

[0081] The single processing quantity and total processing time are set based on the demand evaluation value 'a'.

[0082] The time interval for a single cycle correction is set based on the total processing time of a single operation.

[0083] Specifically, the first and second demand evaluation values ​​have the same range. A mapping table can be established based on historical data, showing the quantity of round steel to be processed versus the first demand evaluation value and the diameter of the round steel to be processed versus the second demand evaluation value. The larger the quantity of round steel to be processed, the larger the corresponding first demand evaluation value; similarly, the larger the diameter of the round steel to be processed, the larger the corresponding second demand evaluation value.

[0084] Specifically, the first and second weighting coefficients can be set based on historical data, and n1+n2=1. The larger the demand evaluation value a, the larger the corresponding single processing quantity and the total processing time. The time interval of its cyclic correction cycle is the same as the total processing time.

[0085] It is understood that in the above embodiments, by establishing a cyclic correction cycle, the processing of 40Mn2 round steel is dynamically corrected. By reducing the final rolling temperature, the surface hardness of 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform, thereby facilitating subsequent sawing and reducing thermal wear.

[0086] In a preferred embodiment of this application, obtaining the hardness evaluation value of the processed round steel from the previous correction cycle includes:

[0087] The number of round steel bars to be sampled is set according to the single processing volume in the previous correction cycle.

[0088] Generate hardness evaluation values ​​for each sampled round steel bar;

[0089] Establish an initial sequence C of hardness evaluation values ​​within the previous correction cycle, C=(c1,c2…c…). m ), where m is the number of sampled round steel bars, and ci is the hardness evaluation value of the i-th sampled round steel bar;

[0090] The initial sequence C of hardness evaluation values ​​is preprocessed to generate a sequence C1, C1=(c1,c2…c m-m1 ), where m1 is the number of hardness evaluation values ​​to be removed;

[0091] The processing evaluation value compensation coefficient e is generated based on m1;

[0092] Based on the hardness evaluation value sequence C1 and the number of processing evaluation value compensations e, the processing evaluation value d of the previous correction cycle is generated;

[0093] d=e ( ) / (m-m1).

[0094] Specifically, an average hardness evaluation value is generated based on the initial sequence C of hardness evaluation values. The difference between each hardness evaluation value is then generated based on the average hardness evaluation value. If the difference between hardness evaluation values ​​is greater than the hardness evaluation value difference threshold, the data is removed. By removing outlier data and marking the processing evaluation value compensation coefficient, the processing evaluation value d becomes more accurate.

[0095] Specifically, when generating the processing evaluation value compensation coefficient e based on m1, it includes:

[0096] Establish the first quantity interval (M1, M2), the second quantity interval (M2, M3), and the third quantity interval (M3, M4).

[0097] If the number of discarded hardness evaluation values ​​m1 falls within the first quantity range, the compensation coefficient e is set to the preset first compensation coefficient e1; if the number of discarded hardness evaluation values ​​m1 falls within the second quantity range, the compensation coefficient e is set to the preset second compensation coefficient e2; if the number of discarded hardness evaluation values ​​m1 falls within the third quantity range, the compensation coefficient e is set to the preset third compensation coefficient e3, and e3 <e2<e1<1。

[0098] In a preferred embodiment of this application, when generating a correction instruction based on the processing evaluation value, the following steps are included:

[0099] Preset the first processing evaluation value threshold and the second processing evaluation value threshold;

[0100] When the processing evaluation value d is less than the preset first processing evaluation value threshold, a final rolling temperature correction command is generated, and a final rolling temperature correction coefficient p1 is generated based on the final rolling temperature correction command.

[0101] Obtain the processing parameters from the previous correction cycle, and generate the preset final rolling temperature v1 and the final rolling temperature fluctuation evaluation value z based on the processing parameters;

[0102] The final rolling temperature compensation coefficient p2 is set based on the final rolling temperature fluctuation evaluation value z.

[0103] The final rolling temperature v, v=p1, is generated for the next cycle correction. p2 v1.

[0104] Specifically, when generating the final rolling temperature fluctuation evaluation value z, the following are included:

[0105] Multiple temperature monitoring nodes are set according to the processing parameters;

[0106] Generate the final rolling temperature at each temperature monitoring time point, and generate the temperature difference value at each temperature monitoring time point based on the preset final rolling steel temperature v1.

[0107] The final rolling temperature fluctuation evaluation value z is set based on all temperature differences.

[0108] Specifically, the larger the rolling temperature fluctuation evaluation value z, the smaller the corresponding final rolling temperature compensation coefficient p2, and p1<1, p2<1.

[0109] Specifically, the first processing evaluation value threshold and the second processing evaluation value threshold can be set based on historical data. The first processing evaluation value threshold is less than the second processing evaluation value threshold. When it is between the two thresholds, it means that the current cycle processing is in normal operation and no adjustment is needed. When it is lower than the first processing evaluation value threshold, it means that the hardness of the round steel does not meet the standard and the processing parameters need to be adjusted. The final rolling temperature is dynamically adjusted by setting the final rolling temperature compensation coefficient p2 and the final rolling temperature correction coefficient p1.

[0110] Specifically, when generating correction instructions based on processing evaluation values, the process also includes:

[0111] When the processing evaluation value d is less than the preset first processing evaluation value threshold, a first-level slow cooling time correction instruction is generated.

[0112] The first slow cooling time correction coefficient p2 is set according to the first-level slow cooling time correction command;

[0113] Obtain the slow cooling duration t1 of the previous correction cycle;

[0114] Based on the first slow cooling duration correction factor p2 and the slow cooling duration t1, the slow cooling duration t of the next correction cycle is set, where t = p2. t1.

[0115] Specifically, when generating correction instructions based on processing evaluation values, the process also includes:

[0116] When the processing evaluation value d is between the preset first processing evaluation value threshold and the preset second processing evaluation value threshold, no correction instruction is generated;

[0117] When the processing evaluation value d is greater than the preset second processing evaluation value threshold, a secondary slow cooling time correction command is generated;

[0118] The second slow cooling time correction coefficient p3 is set according to the second slow cooling time correction command;

[0119] Obtain the slow cooling duration t1 of the previous correction cycle;

[0120] Based on the second slow cooling duration correction factor p3 and the slow cooling duration t1, the slow cooling duration t of the next correction cycle is set, where t = p3. t1.

[0121] Specifically, p2>1, p3<1. The specific values ​​of the first slow cooling time correction coefficient p2 and the second slow cooling time correction coefficient p3 can be set according to historical processing data. The slow cooling time correction command is set according to the real-time processing evaluation value, and the slow cooling time in the pit is dynamically adjusted. Under the premise of ensuring processing quality, the work efficiency is improved, and efficient processing of 40Mn2 round steel is achieved.

[0122] In a preferred embodiment of this application, generating the hardness evaluation value for each sampled round steel bar includes:

[0123] Select a single sample round steel bar

[0124] Multiple hardness test points are set according to the diameter of the sampled round steel.

[0125] Obtain the hardness values ​​of each hardness test point and establish a hardness value sequence F, F=(f1,f2…fg), where g is the number of hardness test points and fi is the hardness value of the i-th test point;

[0126] Generate the average hardness Δf1, the difference hardness Δf2, and the hardness variance k based on the hardness value sequence F;

[0127] The average hardness evaluation value H1 is generated based on the average hardness Δf1.

[0128] The differential hardness evaluation value H2 is generated based on the differential hardness Δf2;

[0129] A compensation coefficient b for hardness evaluation values ​​is generated based on the hardness variance k.

[0130] Generate a hardness evaluation value c, c = b(n3) H1+n4 H2), where n3 is the preset third weight coefficient and n4 is the preset fourth weight coefficient.

[0131] Specifically, the standard hardness is set according to the processing requirements. The smaller the difference between the average hardness Δf1 and the standard hardness, the larger the corresponding average hardness evaluation value H1. The differential hardness refers to the difference between the center hardness and the surface hardness of the round steel. The smaller the differential hardness Δf2, the larger the corresponding differential hardness evaluation value H2.

[0132] Specifically, when generating the hardness evaluation value compensation coefficient b based on the hardness variance k, it includes:

[0133] The first hardness variance interval (K1, K2), the second hardness variance interval (K2, K3), and the third hardness variance interval (K3, K4) are preset.

[0134] If the hardness variance falls within the first hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset first hardness evaluation value compensation coefficient b1; if the hardness variance falls within the second hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset second hardness evaluation value compensation coefficient b2; if the hardness variance falls within the third hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset third hardness evaluation value compensation coefficient b3, and b3 <b2<b1<1。

[0135] According to the first concept of this application, by establishing a cyclic correction cycle, the processing of 40Mn2 round steel is dynamically corrected. By reducing the final rolling temperature, the surface hardness of 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform, thereby facilitating subsequent sawing and reducing thermal wear.

[0136] According to the second concept of this application, by extending the cooling time in the pit, the surface hardness of 40Mn2 round steel is reduced, making the center hardness and surface hardness of the processed 40Mn2 round steel more uniform. At the same time, by dynamically adjusting the cooling time in the pit through cyclic correction, the work efficiency is improved while ensuring the processing quality, thus achieving efficient processing of 40Mn2 round steel.

[0137] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A method for reducing the surface hardness of 40Mn2 steel, characterized in that, include: Establish a cyclic correction cycle based on the parameters of the round steel to be processed; obtain the quantity and diameter of the round steel to be processed. A first demand evaluation value A1 is generated based on the quantity of round steel to be processed; a second demand evaluation value A2 is generated based on the diameter of the round steel to be processed; a demand evaluation value a is generated based on the first demand evaluation value A1 and the second demand evaluation value A2; a = n1 A1+n2 A2, where n1 is a preset first weighting coefficient and n2 is a second weighting coefficient; the single processing quantity and the total processing time are set according to the demand evaluation value a; the time interval of a single cycle correction period is set according to the total processing time. Multiple feedback time nodes are generated based on the cyclic correction cycle. The processing evaluation value of the previous cyclic correction cycle is obtained based on these time nodes. The number of round steel bars to be sampled is set based on the single processing volume within the previous cyclic correction cycle. Hardness evaluation values ​​for each sampled round steel bar are generated. An initial sequence C, C=(c1,c2…c…) of hardness evaluation values ​​within the previous cyclic correction cycle is established. m ), where m is the number of sampled round steel bars, and ci is the hardness evaluation value of the i-th sampled round steel bar; the initial sequence of hardness evaluation values ​​C is preprocessed to generate the hardness evaluation value sequence C1, C1=(c1,c2…c m-m1 ), where m1 is the number of hardness evaluation values ​​removed; a processing evaluation value compensation coefficient e is generated based on m1; and the processing evaluation value d for the previous correction cycle is generated based on the hardness evaluation value sequence C1 and the processing evaluation value compensation number e; d=e ( ) / (m-m1); A correction instruction is generated based on the processing evaluation value, and the processing parameters in the next correction cycle are corrected based on the correction instruction. When generating correction instructions based on processing evaluation values, the following are included: Preset the first processing evaluation value threshold and the second processing evaluation value threshold; When the processing evaluation value is less than a preset first processing evaluation value threshold, a final rolling temperature correction command is generated, and a final rolling temperature correction coefficient p1 is generated according to the final rolling temperature correction command. Obtain the processing parameters from the previous correction cycle, and generate the preset final rolling temperature v1 and the final rolling temperature fluctuation evaluation value z based on the processing parameters; The final rolling temperature compensation coefficient p2 is set based on the final rolling temperature fluctuation evaluation value z. The final rolling temperature v, v=p1, is generated for the next cycle correction. p2 v1; When generating the final rolling temperature fluctuation evaluation value z, the following are included: Multiple temperature monitoring nodes are set according to the processing parameters; Generate the final rolling temperature at each temperature monitoring time point, and generate the temperature difference value at each temperature monitoring time point based on the preset final rolling steel temperature v1. The final rolling temperature fluctuation evaluation value z is set based on all the temperature differences mentioned above; When generating correction instructions based on processing evaluation values, the following are also included: When the processing evaluation value d is less than the preset first processing evaluation value threshold, a first-level slow cooling time correction instruction is generated. The first slow cooling time correction coefficient p2 is set according to the first-level slow cooling time correction command; Obtain the slow cooling duration t1 of the previous correction cycle; Based on the first slow cooling duration correction coefficient p2 and the slow cooling duration t1, the slow cooling duration t of the next cycle correction period is set, where t = p2. t1; When generating correction instructions based on processing evaluation values, the following are also included: When the processing evaluation value d is between the preset first processing evaluation value threshold and the preset second processing evaluation value threshold, no correction instruction is generated; When the processing evaluation value d is greater than the preset second processing evaluation value threshold, a secondary slow cooling time correction command is generated; The second slow cooling time correction coefficient p3 is set according to the secondary slow cooling time correction command; Obtain the slow cooling duration t1 of the previous correction cycle; Based on the second slow cooling duration correction coefficient p3 and the slow cooling duration t1, the slow cooling duration t of the next correction cycle is set, where t = p3. t1.

2. The method for reducing the surface hardness of 40Mn2 steel as described in claim 1, characterized in that, When generating the processing evaluation value compensation coefficient e based on m1, it includes: Establish the first quantity interval (M1, M2), the second quantity interval (M2, M3), and the third quantity interval (M3, M4). If the number of discarded hardness evaluation values ​​m1 falls within the first quantity range, the compensation coefficient e is set to the preset first compensation coefficient e1; if the number of discarded hardness evaluation values ​​m1 falls within the second quantity range, the compensation coefficient e is set to the preset second compensation coefficient e2; if the number of discarded hardness evaluation values ​​m1 falls within the third quantity range, the compensation coefficient e is set to the preset third compensation coefficient e3, and e3 <e2<e1<1。 3. The method for reducing the surface hardness of 40Mn2 steel as described in claim 2, characterized in that, When generating the hardness evaluation values ​​for each sampled round steel bar, the following are included: Select a single sample round steel bar Multiple hardness test points are set according to the diameter of the sampled round steel. Obtain the hardness values ​​of each hardness test point and establish a hardness value sequence F, F=(f1,f2…fg), where g is the number of hardness test points and fi is the hardness value of the i-th test point; Generate the average hardness Δf1, the difference hardness Δf2, and the hardness variance k based on the hardness value sequence F; An average hardness evaluation value H1 is generated based on the average hardness Δf1. A difference hardness evaluation value H2 is generated based on the difference hardness Δf2; A hardness evaluation value compensation coefficient b is generated based on the hardness variance k. Generate a hardness evaluation value c, c = b(n3) H1+n4 H2), where n3 is the preset third weight coefficient and n4 is the preset fourth weight coefficient.

4. The method for reducing the surface hardness of 40Mn2 steel as described in claim 3, characterized in that, When generating the hardness evaluation value compensation coefficient b based on the hardness variance k, the following is included: The first hardness variance interval (K1, K2), the second hardness variance interval (K2, K3), and the third hardness variance interval (K3, K4) are preset. If the hardness variance falls within the first hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset first hardness evaluation value compensation coefficient b1; if the hardness variance falls within the second hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset second hardness evaluation value compensation coefficient b2; if the hardness variance falls within the third hardness variance range, the hardness evaluation value compensation coefficient b is set to the preset third hardness evaluation value compensation coefficient b3, and b3 <b2<b1<1。

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