A crown control method accommodating specification changes

Abstract

The present application relates to a kind of convexity control method suitable for specification change, by configuring the corresponding table of strip target width and target width index, set convexity compensation control parameter, including convexity compensation maximum, convexity compensation minimum, width change threshold, convexity compensation control constant and convexity compensation control coefficient;Strip triggers shape model calculation before entering finishing mill, obtains roll changing information, the information of current strip and previous strip, calculates the convexity compensation according to width change condition, simultaneously considers the influence of roll changing, finally limit check, updates convexity control target and carries out model setting, when strip passes through finishing mill outlet convexity detection unit completely, the target width and target width index of current strip are updated strip information table, for next time calculating convexity compensation.The present application effectively avoids the convexity control deviation caused by strip width change, improves strip convexity control effect and product quality.

Description

Technical Field

[0001] This patent application belongs to the field of hot rolling technology in the metallurgical industry, and more specifically, it relates to a crown control method that adapts to changes in specifications. Background Technology

[0002] In the field of hot rolling technology, the indicators for evaluating strip shape include crown and straightness. Crown, also known as the transverse thickness of the strip, is the thickness difference of the hot-rolled strip along the width direction. Precise control of crown is an important measure to ensure the straightness of the strip and prevent defects such as wedges. Therefore, the control of crown of hot-rolled strip is extremely important in the field of hot rolling technology.

[0003] During the hot rolling process, factors such as rolling schedule, rolling roll period, slab composition, and specification switching can cause the crown control to fail to meet the expected target. In particular, changes in the target width of the strip directly affect the shape of the strip roll gap, resulting in the inability to guarantee the target crown of the first coil after the target width switch, which seriously affects the strip shape quality and yield. Summary of the Invention

[0004] The purpose of this invention is to provide a crown control method that adapts to changes in specifications, thereby solving the shortcomings of poor control of the first coil's target crown after changes in the target width of hot-rolled strip in the prior art.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] A convexity control method adaptable to specification changes, which sets up a correspondence table between the target width w of the strip and the target width index w_idx.

[0007] Set up a convexity compensation control parameter table to calculate the convexity compensation amount after the target width changes. This table includes the maximum convexity compensation amount (crn_comp_max), the minimum convexity compensation amount (crn_comp_min), the width change threshold (wid_chg_lim), the convexity compensation control constant (crn_comp_const), and the convexity compensation control coefficients (a1, a2, c1, and c2).

[0008] Set up a strip information table to record information about the previous strip, including the target width pre_w and the target width index pre_w_idx, and set the initial value to 0.

[0009] When the strip enters the finishing mill and triggers the shape model calculation, it obtains the current strip information, including the target width w and the target width index w_idx. It also obtains the information of the previous strip, including the target width pre_w and the target width index pre_w_idx. The crown compensation amount crn_comp is calculated. If the target width index of the current strip is greater than the target width index of the previous strip, then crn_comp is calculated as follows:

[0010]

[0011] If the current target width index of the strip is less than the target width index of the previous strip, then the calculation method for crn_comp is as follows:

[0012]

[0013] If the current target width index of the strip is equal to the target width index of the previous strip, then the target width change trend is further determined. When the target width increases or remains unchanged, i.e., w ≥ pre_w, then the calculation method for crn_comp is as follows:

[0014]

[0015] If the target width decreases, i.e., w < pre_w, then the calculation method for crn_comp is as follows:

[0016]

[0017] If the width change is less than the width change threshold, then the convexity compensation amount crn_comp = 0.

[0018] To determine the roll change indicator, if two or more finishing mill stands are replaced with new work rolls, then reset the crown compensation amount, i.e., crown compensation amount crn_comp = 0.

[0019] After the convexity compensation amount is calculated, an upper and lower limit check is performed. If the convexity compensation amount is less than the minimum convexity compensation amount crn_comp_min, then the convexity compensation amount = the minimum convexity compensation amount; otherwise, if the convexity compensation amount is greater than the maximum convexity compensation amount crn_comp_max, then the convexity compensation amount = the maximum convexity compensation amount.

[0020] Finally, the original target convexity of the strip is corrected using the convexity compensation amount after the limit check, that is, the control target convexity = original target convexity + convexity compensation amount, and the strip shape is set using the control target convexity.

[0021] Coefficients c1 and c2 are used to calculate the convexity compensation amount when the target width increases and decreases, respectively. The data is stored in the database and a modification interface is provided to easily adjust and optimize the calculated convexity compensation amount.

[0022] After the strip has completely passed through the finish rolling exit crown detection unit, the current target width and target width index of the strip are updated in the strip information table, i.e., pre_w = w, pre_w_idx = w_idx, which are used to set the crown compensation amount for the next strip.

[0023] Furthermore, the correspondence table between the target strip width w and the target width index w_idx includes:

[0024] When w < 1000mm, w_idx is 0; when 1000mm ≤ w < 1150mm, w_idx is 1.

[0025] When 1150mm≤w<1300mm, w_idx is 2; when 1300mm≤w<1450mm, w_idx is 3; when 1450mm≤w<1600mm, w_idx is 4; when 1600mm≤w<1750mm, w_idx is 5; when 1750mm≤w<1900mm, w_idx is 6; when 1900mm≤w, w_idx is 7.

[0026] Furthermore, the maximum convexity compensation value (crn_comp_max) and the minimum convexity compensation value (crn_comp_min) in the convexity compensation control parameter table are used for convexity compensation limit checks. The maximum convexity compensation value (crn_comp_max) ranges from 0.0mm to 0.015mm, preferably set to 0.011mm. The minimum convexity compensation value (crn_comp_min) ranges from -0.015mm to 0.0mm, preferably set to -0.011mm. The width change threshold (wid_chg_lim) is used to calculate the convexity compensation value. When the width change is less than or equal to the width change threshold (wid_chg_lim), the convexity compensation value... The value is 0, meaning no convexity compensation control is performed. The width change threshold wid_chg_lim ranges from 0mm to 20mm, preferably set to 10mm. The convexity compensation control constant crn_comp_const, convexity compensation control coefficients a1 and a2 are parameters for calculating the convexity compensation amount when the target width changes. The convexity compensation control constant crn_comp_const ranges from 1.0 to 1.3, preferably set to 1.2. The convexity compensation control coefficients a1 and a2 are used to calculate the convexity compensation amount when the width index increases and decreases, respectively. The value of a1 ranges from 0.0mm to 0.01mm, preferably set to 0.005mm, and the value of a2 ranges from -0.005mm to 0.0mm, preferably set to -0.005mm.

[0027] Furthermore, the convexity compensation calculation coefficient c1 is used to calculate the convexity compensation amount when the target width increases, and the value range is 0.0 to 0.01, preferably set to 0.005; the convexity compensation calculation coefficient c2 is used to calculate the convexity compensation amount when the target width decreases, and the value range is -0.01 to 0.0, preferably set to -0.003.

[0028] Due to the adoption of the above technical solution, the beneficial effects achieved by this invention are:

[0029] This invention configures a correspondence table between the target strip width and the target width index, and sets crown compensation control parameters, including the maximum and minimum crown compensation values, width change threshold, crown compensation control constant, and crown compensation control coefficient. When the strip enters the finishing mill and triggers the shape model calculation, it acquires roll change information, information about the current strip and the previous strip, calculates the crown compensation amount based on width changes, and considers the impact of roll changes. After a final limit check, the crown control target is updated for model setting. Once the strip has completely passed the crown detection unit at the finishing mill exit, the target width and target width index of the current strip are updated in the strip information table for the next crown compensation calculation. This invention effectively avoids crown control deviations caused by strip width changes, improving strip crown control performance and product quality. Attached Figure Description

[0030] Figure 1 This is a flowchart of the control method of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the embodiments.

[0032] This invention provides a crown control method that adapts to changes in strip width, thus overcoming the shortcomings of existing technologies where low crown control accuracy of the first coil after strip width changes negatively impacts product quality and production stability. See also... Figure 1 This invention provides a convexity control method that adapts to specification changes, comprising the following steps:

[0033] Step 101: Set up a table to correspond to the target width w of the strip and the target width index w_idx.

[0034] The table mapping strip target width w to target width index w_idx includes:

[0035] When w < 1000mm, w_idx is 0; when 1000mm ≤ w < 1150mm, w_idx is 1.

[0036] When 1150mm≤w<1300mm, w_idx is 2; when 1300mm≤w<1450mm, w_idx is 3; when 1450mm≤w<1600mm, w_idx is 4; when 1600mm≤w<1750mm, w_idx is 5; when 1750mm≤w<1900mm, w_idx is 6; when 1900mm≤w, w_idx is 7.

[0037] Step 102: Set up a convexity compensation control parameter table to calculate the convexity compensation amount after the target width changes. This table includes the maximum convexity compensation amount crn_comp_max, the minimum convexity compensation amount crn_comp_min, the width change threshold wid_chg_lim, the convexity compensation control constant crn_comp_const, and the convexity compensation control coefficients a1, a2, c1, and c2.

[0038] In the convexity compensation control parameter table, the maximum convexity compensation value crn_comp_max and the minimum convexity compensation value crn_comp_min are used for convexity compensation limit checks. The maximum convexity compensation value crn_comp_max ranges from 0.0mm to 0.015mm, preferably set to 0.011mm. The minimum convexity compensation value crn_comp_min ranges from -0.015mm to 0.0mm, preferably set to -0.011mm.

[0039] The width change threshold wid_chg_lim is used to calculate the convexity compensation amount. When the width change amount is less than or equal to the width change threshold wid_chg_lim, the convexity compensation amount is 0, that is, no convexity compensation control is performed. The width change threshold wid_chg_lim ranges from 0mm to 20mm. Preferably, the width change threshold wid_chg_lim is set to 10mm.

[0040] The convexity compensation control constant crn_comp_const, convexity compensation control coefficients a1 and a2 are parameters for calculating the convexity compensation amount when the target width changes. The convexity compensation control constant crn_comp_const has a value range of 1.0 to 1.3, preferably set to 1.2. The convexity compensation control coefficients a1 and a2 are used to calculate the convexity compensation amount when the width index increases and decreases, respectively. The value range of a1 is 0.0mm to 0.01mm, preferably set to 0.005mm, and the value range of a2 is -0.005mm to 0.0mm, preferably set to -0.005mm.

[0041] The convexity compensation calculation coefficient c1 is used to calculate the convexity compensation amount when the target width increases, and the value range is 0.0 to 0.01, preferably 0.005; the convexity compensation calculation coefficient c2 is used to calculate the convexity compensation amount when the target width decreases, and the value range is -0.01 to 0.0, preferably -0.003.

[0042] Step 103: Set up a strip information table to record the information of the previous strip, including the target width pre_w, the target width index pre_w_idx, and set the initial value to 0.

[0043] Step 104: When the strip enters the finishing mill and triggers the shape model calculation, information about the current strip and the previous strip is obtained, including the target width and target width index. The crown compensation amount is calculated based on the width changes. The information record of the previous strip includes the previous target width pre_w and the previous target width index pre_w_idx. The crown compensation amount crn_comp is calculated based on the target width changes. Simultaneously, the roll change flag is obtained, and the crown compensation amount crn_comp is reset according to the roll change flag to obtain the final crown compensation amount crn_comp. The crown compensation amount crn_comp is then used to update the crown control target for model setting.

[0044] The convexity compensation amount is denoted as crn_comp. If the target width index of the current strip is greater than the target width index of the previous strip, then crn_comp is calculated as follows:

[0045]

[0046] If the current target width index of the strip is less than the target width index of the previous strip, then the calculation method for crn_comp is as follows:

[0047]

[0048] If the current target width index of the strip is equal to the target width index of the previous strip, then the target width change trend is further determined. When the target width increases or remains unchanged, i.e., w ≥ pre_w, then the calculation method for crn_comp is as follows:

[0049]

[0050] If the target width decreases, i.e., w < pre_w, then the calculation method for crn_comp is as follows:

[0051]

[0052] In the formula, crn_comp is the convexity compensation amount, crn_comp_const is the convexity compensation control constant, w is the target width of the current strip, pre_w is the target width of the previous piece, and a1, a2, c1 and c2 are the convexity compensation control coefficients.

[0053] If the width change is less than the width change threshold, then the convexity compensation amount crn_comp = 0.

[0054] To determine the roll change indicator, if two or more finishing mill stands are replaced with new work rolls, then reset the crown compensation amount, i.e., crown compensation amount crn_comp = 0.

[0055] Step 105: After the convexity compensation amount crn_comp is calculated, a further upper and lower limit check (also called limit check) is performed. If the convexity compensation amount is less than the minimum convexity compensation amount crn_comp_min, then the convexity compensation amount = the minimum convexity compensation amount; otherwise, if the convexity compensation amount is greater than the maximum convexity compensation amount crn_comp_max, then the convexity compensation amount = the maximum convexity compensation amount, that is, the control target convexity = the original target convexity + the convexity compensation amount crn_comp, and the control target convexity is used to set the plate shape.

[0056] Step 106: After the upper and lower limit checks are completed, the original target convexity of the strip is corrected by the convexity compensation amount after the limit check. That is, the control target convexity = the original target convexity + the convexity compensation amount. The strip shape is set by using the control target convexity.

[0057] Next, after the strip has completely passed through the crown detection unit at the finishing mill exit, the target width w and target width index w_idx of the current strip are updated in the strip information table, that is, pre_w = w, pre_w_idx = w_idx, which are used to set the crown compensation amount for the next strip.

[0058] The strip information table stores information about the previous strip, including the target width pre_w and the target width index pre_w_idx. When the strip has completely passed through the finishing mill exit crown detection unit, the information is updated, i.e., pre_w = w and pre_w_idx = w_idx, which is used to set the crown compensation amount for the next strip.

[0059] The following typical application example will further illustrate the technical solution of this embodiment:

[0060] In a certain hot rolling production line, the finishing mill is a 7-stand continuous rolling mill. The process control system is configured with a correspondence table between the target strip width w and the target width index w_idx, as shown in Table 1.

[0061] w < 1000 mm 0 1000mm≤w<1150mm 1 1150mm≤w<1300mm 2 1300mm≤w<1450mm 3 1450mm≤w<1600mm 4 1600mm≤w<1750mm 5 1750mm≤w<1900mm 6 1900mm≤w 7

[0062] Table 1

[0063] The control parameters in the convexity compensation control parameter table are set, where the maximum convexity compensation value (crn_comp_max) and the minimum convexity compensation value (crn_comp_min) are used for convexity compensation limit checks. The maximum convexity compensation value (crn_comp_max) ranges from 0.0mm to 0.015mm, preferably set to 0.011mm. The minimum convexity compensation value (crn_comp_min) ranges from -0.015mm to 0mm, preferably set to -0.011mm. The width variation threshold (wid_chg_lim) ranges from 0mm to 20mm, preferably set to [value missing]. The change threshold `wid_chg_lim` is 10 mm; the convexity compensation control constant `crn_comp_const` has a value range of 1.0 to 1.3, preferably 1.2; the value range of `a1` is 0.0 mm to 0.01 mm, preferably 0.005 mm; the value range of `a2` is -0.005 mm to 0.0 mm, preferably -0.005 mm; the convexity compensation calculation coefficient `c1` is used to calculate the convexity compensation amount when the target width increases, with a value range of 0.0 to 0.01, preferably 0.005; the convexity compensation calculation coefficient `c2` is used to calculate the convexity compensation amount when the target width decreases, with a value range of -0.01 to 0.0, preferably -0.003.

[0064] Set up a strip information table to record information about the previous strip, including the target width pre_w and the target width index pre_w_idx, and set the initial value to 0.

[0065] The strip steel production sequence is strip steel 0, strip steel 1, strip steel 2, ... After strip steel 0 is produced, the finishing mill stand 7 undergoes a roll change. Finishing strip steel 1 is the first strip after the roll change. The information for strip steel 0 includes: initial target crown of 0.04mm, target width w of 1550mm, and corresponding target width index of 4; the information for strip steel 1 includes: initial target crown of 0.04mm, target width w of 1250mm, and corresponding target width index of 2; the information for strip steel 2 includes: initial target crown of 0.04mm, target width w of 1350mm, and corresponding target width index of 2.

[0066] After the strip steel 0 is completed in the finishing rolling process, once all the strip steel has passed through the finishing rolling exit crown detection unit, update the strip steel information table to pre_w = 1550mm and pre_w_idx = 4.

[0067] When strip 1 enters the finishing mill and triggers the shape model calculation, it obtains information about the current strip and the previous strip. The initial target crown of the current strip is 0.04mm, the target width w is 1250, and the target width index w_idx is 2. The target width pre_w of the previous strip is 1550mm, and the target width index pre_w_idx is 4. Because w_idx < pre_w_idx, that is, the target width index of the current strip is less than the target width index of the previous strip, the crown compensation amount crn_comp is calculated as follows:

[0068]

[0069] Further, it is determined whether the width change is less than the width change threshold. When comparing strip 1 and strip 0, the width change is 1550-1250=200 (mm), and the width change threshold is wid_chg_lim=10mm. The width change of strip 1 is greater than the width change threshold, and the convexity compensation remains unchanged at -0.01784.

[0070] Further, the roll change indicator is determined. Since the finishing mill roll change stand is 7, which is greater than 2 stands, the crown compensation amount is reset, i.e., the crown compensation amount crn_comp = 0.

[0071] Furthermore, an upper and lower limit check is performed. Since the convexity compensation amount is before the minimum and maximum values ​​of the convexity compensation amount, the convexity compensation amount crn_comp = 0 is maintained.

[0072] Furthermore, the control convexity target = original target convexity + convexity compensation amount = 0.04 + 0 = 0.04 (mm), and the plate shape is set using a convexity target of 0.04 mm.

[0073] After strip 1 has completely passed through the finish rolling exit crown detection unit, the strip information table is updated using the target width and target width index of strip 1, i.e., pre_w = 1250, pre_w_idx = 2.

[0074] When strip 2 enters the finishing mill and triggers the shape model calculation, it obtains information about the current strip and the previous strip. The initial target crown of the current strip is 0.04mm, the target width w is 1350, and the target width index w_idx is 3. The target width pre_w of the previous strip is 1250mm, and the target width index pre_w_idx is 2. Because w_idx > pre_w_idx, that is, the target width index of the current strip is greater than the target width index of the previous strip, the crown compensation amount crn_comp is calculated as follows:

[0075]

[0076]

[0077] Further, it is determined whether the width change is less than the width change threshold. Compared with strip 1, the width change of strip 2 is 1350-1250=100 (mm), and the width change threshold is wid_chg_lim=10mm. The width change of strip 2 is greater than the width change threshold, and the convexity compensation remains unchanged at 0.011798mm.

[0078] Furthermore, judging from the roll change mark, since the rolls were not changed before the finishing rolling of strip 2, the crown compensation amount is not reset and remains unchanged at 0.011798mm.

[0079] Further, an upper and lower limit check is performed. The convexity compensation amount of 0.011798mm is greater than the maximum convexity compensation amount of 0.011mm. Therefore, the convexity compensation amount = the maximum convexity compensation amount = 0.011mm.

[0080] Furthermore, the control convexity target = original target convexity + convexity compensation amount = 0.04 + 0.011 = 0.051 (mm), and the plate shape is set using a convexity target of 0.051 mm.

[0081] After strip 2 has completely passed through the finishing mill exit crown detection unit, the strip information table is updated using the target width and target width index of strip 1, i.e., pre_w = 1350, pre_w_idx = 3.

[0082] The one or more technical solutions provided in the embodiments of the present invention have at least the following beneficial effects:

[0083] This invention provides a crown control method that adapts to specification changes. It configures a correspondence table between the target width of the strip and its target width index, and sets crown compensation control parameters, including the maximum crown compensation value, the minimum crown compensation value, the width change threshold, the crown compensation control constant, and the crown compensation control coefficient. When the strip enters the finishing mill and triggers the shape model calculation, it acquires roll change information, information about the current strip and the previous strip, calculates the crown compensation amount based on the width change, and considers the impact of roll change. After a final limit check, it updates the crown control target and sets the model. When the strip completely passes through the crown detection unit at the finishing mill exit, it updates the strip information table with the current target width and target width index for the next crown compensation calculation.

[0084] This invention calculates the crown compensation amount based on roll change mark determination and strip information comparison, and corrects and controls the target crown and sets the strip shape. It effectively avoids the problem that the crown target of the first roll cannot be guaranteed due to the influence of roll gap crown after the target width is switched, thus improving the strip crown control effect and product quality.

[0085] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A convexity control method adapting to specification changes, characterized in that... Includes the following steps: S101. Set up a table to correspond to the target width w of the strip and the target width index w_idx; S102. Set the convexity compensation control parameter table. This table is used to calculate the convexity compensation amount after the target width changes. The table includes the maximum convexity compensation amount crn_comp_max, the minimum convexity compensation amount crn_comp_min, the width change threshold wid_chg_lim, the convexity compensation control constant crn_comp_const, and the convexity compensation control coefficient. The maximum convexity compensation value crn_comp_max and the minimum convexity compensation value crn_comp_min are used to check the upper and lower limits of the convexity compensation value crn_comp. The width variation threshold wid_chg_lim is used to calculate the convexity compensation amount crn_comp; The convexity compensation control constant crn_comp_const and the convexity compensation control coefficient are parameters used to calculate the convexity compensation amount crn_comp when the target width changes. S103. Set up a strip information table to record the information of the previous strip, including the target width of the previous strip pre_w and the index of the target width of the previous strip pre_w_idx, and set the initial value to 0. S104. When the strip enters the finishing mill and triggers the shape model calculation, the roll change information, the current strip information, and the previous strip information are obtained. The current strip information includes the target width w and the target width index w_idx. The previous strip information record includes the previous target width pre_w and the previous target width index pre_w_idx. The crown compensation amount crn_comp is calculated based on the target width change. At the same time, the roll change flag is obtained, and the crown compensation amount crn_comp is reset according to the roll change flag to obtain the final crown compensation amount crn_comp. S105. After the crown compensation amount crn_comp is calculated, the upper and lower limits are checked. The final crown compensation amount crn_comp is used to correct the original target crown of the strip, that is, the control target crown = the original target crown + the crown compensation amount crn_comp. The control target crown is used to set the strip shape. S106. After the upper and lower limit checks are completed, once the strip has completely passed through the finishing mill exit crown detection unit, the current strip target width w and target width index w_idx are updated to the strip information table for use in the next strip setting calculation of crown compensation amount crn_comp.

2. The convexity control method adapting to specification changes according to claim 1, characterized in that: In S101, the correspondence table between the target width w of the strip and the target width index w_idx is set according to the target width range of the strip, and the target width index w_idx ranges from 0 to 7.

3. The convexity control method adapting to specification changes according to claim 2, characterized in that: In S101, the correspondence table between the target strip width w and the target width index w_idx includes: When w < 1000mm, w_idx is 0; When 1000mm≤w<1150mm, w_idx is 1; When 1150mm≤w<1300mm, w_idx is 2; When 1300mm≤w<1450mm, w_idx is 3; When 1450mm≤w<1600mm, w_idx is 4; When 1600mm≤w<1750mm, w_idx is 5; When 1750mm≤w<1900mm, w_idx is 6; When 1900mm≤w, w_idx is 7.

4. The convexity control method adapting to specification changes according to claim 1, characterized in that: In S102, the maximum convexity compensation value, crn_comp_max, ranges from 0.0mm to 0.015mm, and the minimum convexity compensation value, crn_comp_min, ranges from -0.015mm to 0.0mm.

5. The convexity control method adapting to specification changes according to claim 4, characterized in that: In S102, the convexity compensation control constant crn_comp_const has a value range of 1.0 to 1.

3.

6. The convexity control method adapting to specification changes according to claim 5, characterized in that: The convexity compensation control coefficients include a1, a2, c1, and c2. Coefficients a1 and a2 are used to calculate the convexity compensation amount crn_comp when the target width index w_idx increases and decreases, respectively. Coefficients c1 and c2 are used to calculate the convexity compensation amount crn_comp when the target width w increases and decreases, respectively. The value of a1 ranges from 0.0mm to 0.01mm, the value of a2 ranges from -0.005mm to 0.0mm, the value of c1 ranges from 0.0 to 0.01, and the value of c2 ranges from -0.01 to 0.

0.

7. The convexity control method adapting to specification changes according to claim 6, characterized in that: In S104, the phrase "calculate the convexity compensation amount crn_comp based on the change in target width" specifically includes five cases: the target width index w_idx increases, the target width index w_idx decreases, the target width index w_idx remains unchanged, the target width decreases, and the change in target width is ≤ the width change threshold. When the target width index w_idx increases, the convexity compensation amount crn_comp is calculated as follows: ； When the target width index w_idx decreases, the convexity compensation amount crn_comp is calculated as follows: ； When the target width index w_idx remains unchanged, the trend of target width w is further determined. When the target width w increases or remains unchanged, i.e., w ≥ pre_w, the calculation method is as follows: ； When the target width w decreases, i.e., w < pre_w, the calculation method is as follows: ； If the change in target width is less than or equal to the width change threshold wid_chg_lim, then the convexity compensation amount crn_comp = 0.

8. The convexity control method adapting to specification changes according to claim 7, characterized in that: In S104, "resetting the crown compensation amount crn_comp according to the roll change mark" means determining the number of roll change stands in the finishing mill when the strip enters the finishing mill. If the number of roll change stands is greater than or equal to 2, the crown compensation amount crn_comp is set to 0, and crown compensation control is not required.

9. A convexity control method adapting to specification changes according to any one of claims 1-8, characterized in that: In S105, "perform upper and lower limit checks" means that if the convexity compensation amount crn_comp is less than the minimum convexity compensation amount crn_comp_min, then the convexity compensation amount crn_comp = the minimum convexity compensation amount crn_comp_min; otherwise, if the convexity compensation amount crn_comp is greater than the maximum convexity compensation amount crn_comp_max, then the convexity compensation amount crn_comp = the maximum convexity compensation amount crn_comp_max.

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