Finish rolling steel biting impact roll gap compensation method and system

Abstract

The invention provides a finish rolling steel biting impact roll gap compensation method and system. The method comprises the steps that the roll gap set value of each finish rolling rack is obtained; and before a first finish rolling rack bites steel, a corresponding finish rolling rack roll gap adjusting strategy is executed according to the strip steel thickness specification so as to compensate roll gap impact after steel bites, and the thickness of the head of the strip steel after finish rolling meets the preset thickness requirement. The problem that the head of the strip steel is ultra-thick due to the fact that a rolling mill roll gap is bounced off at the moment of steel biting of the finish rolling strip steel is effectively solved, and the head and full-length thickness control precision of the finished strip steel is effectively improved; repeated occurrence of accidents of loop rising and steel piling caused by mismatched second flow between racks due to the fact that the head thickness is too thick and serious and an F7 roll gap is too large after AGC feedback rapid pressing is avoided, and the rolling stability of a production line is improved.

Description

Technical Field

[0001] The invention relates to the application field of steel production, and in particular to a method and system for compensating a roller gap between steel bites and impacts during finishing rolling. Background Art

[0002] During the finishing rolling process of hot strip steel, the thickness of the finished strip head is precisely controlled by calculating the F1-F7 stand roll gap through the measured temperature of the intermediate billet finishing entrance pyrometer. At the moment when the strip head enters the rolling mill to bite the steel, the upper and lower working rolls of the rolling mill press down the strip, and the strip exerts a reverse force on the rolling mill (the rolling mill produces a bounce roll gap), which causes the mill roll gap to be bounced open at the moment when each stand of the finishing rolling bites the steel, and the original secondary preset roll gap value cannot be maintained. In severe cases, the roll gap is bounced open by more than +500um, resulting in a large deviation between the actual roll gap of the strip head and the secondary preset roll gap, resulting in a large deviation between the actual execution roll gap of the strip head and the secondary preset roll gap, and the finished strip head is too thick, affecting the thickness control accuracy of the finished strip head; at the same time, when the strip head is too thick, the thickness feedback control (AGC) quickly presses down the F7 stand roll gap, resulting in mismatch of the second flow rate between the stands, affecting the finishing rolling stability. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention proposes a method and system for compensating the roll gap caused by steel biting in finishing rolling, which mainly solves the problem that the roll gap of the existing finishing rolling mill is bounced open at the moment of steel biting, which may cause the thickness of the strip head to be too thick, thereby affecting the product thickness quality and control accuracy.

[0004] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows.

[0005] The present application provides a method for compensating the roll gap caused by the impact of steel biting in finishing rolling, comprising: obtaining the roll gap setting value of each finishing rolling stand; before the first finishing rolling stand bites steel, executing the corresponding finishing rolling stand roll gap adjustment strategy according to the strip thickness specification to compensate for the roll gap impact after the steel biting, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

[0006] In one embodiment of the present application, the method further comprises: within a preset time interval after the first finishing rolling stand bites steel, restoring the roll gap control value with the finishing rolling stand to the roll gap set value.

[0007] In one embodiment of the present application, the step of executing the corresponding finishing mill stand roll gap adjustment strategy according to the strip thickness specification to compensate for the roll gap impact after biting the steel includes: comparing the strip thickness specification with a preset control thickness threshold to determine the control interval within which the corresponding strip thickness specification falls; and calling the corresponding roll gap adjustment strategy according to the control interval.

[0008] In one embodiment of the present application, the roll gap adjustment strategy includes: when the control interval is less than or equal to 6 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to sixth finishing rolling stands is reduced by 0.2 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.25 mm.

[0009] In one embodiment of the present application, the roll gap adjustment strategy includes: when the control interval is greater than 6 mm and less than or equal to 12 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.2 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.25 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.3 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.35 mm.

[0010] In one embodiment of the present application, the roll gap adjustment strategy includes: when the control interval is greater than 12 mm and less than or equal to 16 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.2 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.25 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.35 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.4 mm.

[0011] In one embodiment of the present application, the roll gap adjustment strategy includes: when the control interval is greater than 16 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.25 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.3 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.4 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.45 mm.

[0012] In one embodiment of the present application, after different roll gap adjustment strategies are executed, the preset time intervals for returning to the roll gap setting value are different.

[0013] The present application also provides a finishing rolling steel biting impact roll gap compensation system, including: a data acquisition module, used to obtain the roll gap setting value of each finishing rolling stand; a roll gap compensation module, used to execute the corresponding finishing rolling stand roll gap adjustment strategy according to the strip thickness specification before the first finishing rolling stand bites the steel to compensate for the roll gap impact after the steel biting, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

[0014] As described above, the method and system for compensating the roller gap caused by steel biting during finishing rolling proposed in the present application have the following beneficial effects.

[0015] The present application performs preset roll gap impact compensation before the strip bites the steel in the first finishing rolling stand. By pre-adjusting the impact roll gap value of the corresponding stand, the deviation between the roll gap actually executed when the strip head passes through the strip and the roll gap set value is reduced, which can effectively reduce the problem of excessive thickness of the strip head, improve the product thickness quality and the full-length thickness control accuracy, and enhance the stability of finishing rolling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of a method for compensating the roller gap during finishing rolling steel biting impact in one embodiment of the present application.

[0017] Figure 2 This is a module diagram of a roller gap compensation system for finishing rolling steel biting impact in one embodiment of the present application. DETAILED DESCRIPTION

[0018] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0020] The inventors have found that:

[0021] The existing control technology has no effective control measures for the problem of the roll gap being bounced open at the moment the finishing rolling F1-F7 stands bite the steel, resulting in frequent excessive thickness of the strip head, affecting the product quality precision control, and there is a risk of high thickness non-quality objections; when the strip head is seriously excessively thick, the AGC feedback control quickly presses down the roll gap of the F7 stand, affecting the finishing rolling stability. There have been multiple cases where the roll gap was pressed too much during the thickness feedback control, resulting in mismatched second flow rates between stands and steel piling accidents.

[0022] Based on the above problems existing in the prior art, the present application proposes a method and system for compensating the roller gap caused by steel biting during finishing rolling. The technical solution of the present application is elaborated in detail below in conjunction with specific embodiments.

[0023] See also Figure 1 , Figure 1 This is a flow chart of a method for compensating the roller gap during finishing rolling steel biting in an embodiment of the present application. The method provided in the embodiment of the present application includes:

[0024] Step S100, obtaining the roll gap setting value of each finishing rolling stand.

[0025] In one embodiment, before the finishing rolling intermediate billet is fed into the steel, the control end will issue a secondary preset roll gap, and each finishing rolling stand will be pre-adjusted according to the secondary preset roll gap before performing finishing rolling. The secondary preset roll gap is the roll gap setting value.

[0026] Step S110, before the first finishing rolling stand bites the steel, the corresponding finishing rolling stand roll gap adjustment strategy is executed according to the strip thickness specification to compensate for the roll gap impact after biting the steel, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

[0027] In one embodiment, in order to avoid a large deviation between the actual roll gap at the moment of finishing rolling biting steel and the roll gap setting value, it is necessary to optimize the roll gap control logic at the moment of finishing rolling biting steel, thereby realizing accurate control of the strip head thickness. In this embodiment of the application, an impact roll gap compensation control is added before the first stand of finishing rolling biting steel, so as to realize the execution roll gap adjustment of the corresponding finishing stand.

[0028] In one embodiment, after the roll gap adjustment before biting steel is completed, after the corresponding frame biting steel, the actual execution roll gap recovery value of each frame is set to the roll gap setting value within a preset time to ensure the thickness control accuracy and stability of subsequent strip rolling. The preset time here can be set according to different roll gap adjustment strategies and different strip thickness specifications.

[0029] In one embodiment, the step of executing the corresponding finishing mill stand roll gap adjustment strategy according to the strip thickness specification to compensate for the roll gap impact after biting the steel includes: comparing the strip thickness specification with a preset control thickness threshold to determine the control interval in which the corresponding strip thickness specification falls; and calling the corresponding roll gap adjustment strategy according to the control interval. Different roll gap adjustment strategies can be associated with corresponding control intervals in advance, and the endpoints of the control interval are used as corresponding control thickness thresholds. The thickness specification of the currently produced strip is compared with the corresponding control thickness threshold, and the control interval in which the current strip thickness specification falls can be determined, and then the associated roll gap adjustment strategy can be called.

[0030] In one embodiment, the roll gap adjustment strategy includes: when the control interval is less than or equal to 6mm, before the first finishing stand bites the steel, the roll gap of the first to sixth finishing stands is reduced by 0.2mm, and the roll gap of the seventh finishing stand is reduced by 0.25mm. When the control thickness is less than or equal to 6.0mm, after the finishing secondary setting sends the roll gap setting value of the F1-F7 stands, on the basis of the secondary roll gap setting, before the F1 stand bites the steel, the roll gap of the F1-F6 stands is automatically reduced by -0.2mm, and the roll gap of the F7 stand is automatically reduced by -0.25mm;

[0031] 0.1s after the finishing rolling F1-F7 stands bite the steel (i.e. 0.1s after the rising edge of the F1-F7 stands bite the steel signal), the roll gap automatically returns to the secondary preset roll gap value, i.e. the roll gap of the F1-F6 stands automatically rises by +0.2mm, and the roll gap of the F7 stand automatically rises by +0.25mm;

[0032] Taking the rolling thickness of 3.39mm as an example, the secondary preset roll gap is: 2392.38, 1373.14, 818.25, 714.81, 452.84, 442.43, 370.98 [10um]. After the compensation of the steel bite impact roll gap, the actual roll gap is: 2372.38, 1353.14, 798.25, 694.81, 432.84, 422.43, 3 45.98[10um], 0.1s after the F1-F7 frame biting steel signal arrives, each frame recovers to the secondary preset roll gap: 2392.38, 1373.14, 818.25, 714.81, 452.84, 442.43, 370.98[10um], so that when the roll gap is opened at the moment when the strip head of each frame bites steel, the roll gap is pressed down in advance to ensure normal control of the strip head thickness.

[0033] In one embodiment, the roll gap adjustment strategy includes: when the control interval is greater than 6mm and less than or equal to 12mm, before the first finishing stand bites the steel, the roll gaps of the first to fourth finishing stands are reduced by 0.2mm, the roll gaps of the fifth finishing stand are reduced by 0.25mm, the roll gaps of the sixth finishing stand are reduced by 0.3mm, and the roll gaps of the seventh finishing stand are reduced by 0.35mm. When 6.0mm<control thickness<=12.0mm, before the F1 stand bites the steel, the roll gaps of the F1-F4 stands are automatically reduced by -0.2mm, the roll gaps of the F5 stand are automatically reduced by -0.25mm, the roll gaps of the F6 stand are automatically reduced by -0.3mm, and the roll gaps of the F7 stand are automatically reduced by -0.35mm;

[0034] 0.15s after the finishing rolling F1-F7 stands bite the steel (i.e. 0.15s after the F1-F7 stands bite the steel signal), the roll gap automatically returns to the secondary preset roll gap value, i.e. the roll gap of the F1-F4 stands automatically rises by +0.2mm, the roll gap of the F5 stand automatically rises by +0.25mm, the roll gap of the F6 stand automatically rises by +0.3mm, and the roll gap of the F7 stand automatically rises by +0.35mm;

[0035] Taking the rolling thickness of 9.7mm as an example, the secondary preset roll gap is: 3305.76, 2395.96, 1810.66, 1531.51, 1180.64, 1052.24, 986.34 [unit: 10um], and the actual roll gap after the bite steel impact roll gap compensation is: 3285.76, 2375.96, 1790.66, 1511.51, 1155.64, 1022.24, 95 1.34 [unit: 10um], 0.15s after the F1-F7 frame biting steel signal arrives, each frame recovers to the second-level preset roll gap: 3305.76, 2395.96, 1810.66, 1531.51, 1180.64, 1052.24, 986.34 [unit: 10um], so that when the roll gap is bounced open at the moment of the strip head biting steel on each frame, the roll gap is pressed down in advance to ensure normal control of the strip head thickness.

[0036] In one embodiment, the roll gap adjustment strategy includes: when the control interval is greater than 12mm and less than or equal to 16mm, before the first finishing stand bites the steel, the roll gaps of the first to fourth finishing stands are reduced by 0.2mm, the roll gaps of the fifth finishing stand are reduced by 0.25mm, the roll gaps of the sixth finishing stand are reduced by 0.35mm, and the roll gaps of the seventh finishing stand are reduced by 0.4mm. When 12.0mm<control thickness<=16.0mm, before the F1 stand bites the steel, the roll gaps of the F1-F4 stands are automatically reduced by -0.2mm, the roll gaps of the F5 stand are automatically reduced by -0.25mm, the roll gaps of the F6 stand are automatically reduced by -0.35mm, and the roll gaps of the F7 stand are automatically reduced by -0.4mm;

[0037] 0.15s after the finishing rolling F1-F7 stands bite the steel (i.e. 0.15s after the F1-F7 stands bite the steel signal), the roll gap automatically returns to the secondary preset roll gap value, i.e. the roll gap of the F1-F4 stands automatically rises by +0.2mm, the roll gap of the F5 stand automatically rises by +0.25mm, the roll gap of the F6 stand automatically rises by +0.35mm, and the roll gap of the F7 stand automatically rises by +0.4mm;

[0038] Taking the rolling thickness of 14.0mm as an example, the secondary preset roll gap is: 3837.48, 2840.81, 2151.85, 1731.12, 3030.22, 1536.56, 1426.42 [10um]. After the compensation of the steel bite impact roll gap, the actual roll gap is: 3817.48, 2820.81, 2131.85, 1711.12, 3005.22, 1501.56, 1386.42[10um], 0.15s after the F1-F7 frame biting steel signal arrives, each frame recovers to the second-level preset roll gap: 3837.48, 2840.81, 2151.85, 1731.12, 3030.22, 1536.56, 1426.42[10um], so that when the roll gap is bounced open at the moment when the strip head of each frame bites steel, the roll gap is pressed down in advance to ensure normal control of the strip head thickness.

[0039] In one embodiment, the roll gap adjustment strategy includes: when the control interval is greater than 16mm, before the first finishing stand bites the steel, the roll gaps of the first to fourth finishing stands are reduced by 0.25mm, the roll gaps of the fifth finishing stand are reduced by 0.3mm, the roll gaps of the sixth finishing stand are reduced by 0.4mm, and the roll gaps of the seventh finishing stand are reduced by 0.45mm. When the control thickness is 16.0mm<, before the F1 stand bites the steel, the roll gaps of the F1-F4 stands are automatically reduced by -0.25mm, the roll gaps of the F5 stand are automatically reduced by -0.3mm, the roll gaps of the F6 stand are automatically reduced by -0.4mm, and the roll gaps of the F7 stand are automatically reduced by -0.45mm;

[0040] 0.2s after the finishing rolling F1-F7 stands bite the steel (i.e. 0.2s after the F1-F7 stands bite the steel signal), the roll gap automatically returns to the secondary preset roll gap value, i.e. the roll gap of the F1-F4 stands automatically rises by +0.25mm, the roll gap of the F5 stand automatically rises by +0.3mm, the roll gap of the F6 stand automatically rises by +0.4mm, and the roll gap of the F7 stand automatically rises by +0.45mm;

[0041] Taking the rolling thickness of 20.1mm as an example, the secondary preset roll gap is: 4271.53, 3417.32, 2737.46, 2404.18, 3853.10, 2147.89, 2024.95 [10um]. After the compensation of the steel bite impact roll gap, the actual roll gap is: 4246.53, 3392.32, 2712.46, 2379.18, 3823.10, 2107.89, 1979.95[10um], 0.2s after the F1-F7 frame steel biting signal arrives, each frame recovers to the second-level preset roll gap: 4271.53, 3417.32, 2737.46, 2404.18, 3853.10, 2147.89, 2024.95[10um], so that when the roll gap is bounced open at the moment of the strip head biting the steel of each frame, the roll gap is pressed down in advance to ensure the normal thickness control of the strip head.

[0042] See also Figure 2 , Figure 2 The module diagram of the roller gap compensation system for the impact of steel biting in finishing rolling in one embodiment of the present application is shown. The system includes: a data acquisition module 20, which is used to obtain the roller gap setting value of each finishing rolling stand; a roller gap compensation module 21, which is used to execute the corresponding roller gap adjustment strategy of the finishing rolling stand according to the strip thickness specification before the first finishing rolling stand bites steel to compensate for the roller gap impact after the steel biting, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

[0043] The execution process of the specific system has been described in detail in the aforementioned method embodiment and will not be repeated here.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for compensating the gap between steel and rollers during finishing rolling, characterized in that: include: Obtaining the roll gap setting value of each finishing mill stand; Before the first finishing rolling stand bites the steel, the corresponding finishing rolling stand roll gap adjustment strategy is executed according to the strip thickness specification to compensate for the roll gap impact after biting the steel, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

2. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 1, characterized in that: The method further comprises: Within a preset time interval after the first finishing rolling stand bites steel, the roll gap control value of the finishing rolling stand is restored to the roll gap set value.

3. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 2, characterized in that: The steps of executing the corresponding finishing mill stand roll gap adjustment strategy according to the strip thickness specification to compensate for the roll gap impact after biting the steel include: Comparing the strip steel thickness specification with a preset control thickness threshold to determine a control interval within which the corresponding strip steel thickness specification falls; The corresponding roll gap adjustment strategy is called according to the control interval.

4. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 3, characterized in that: The roll gap adjustment strategy includes: when the control interval is less than or equal to 6 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to sixth finishing rolling stands is reduced by 0.2 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.25 mm.

5. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 3, characterized in that: The roll gap adjustment strategy includes: when the control interval is greater than 6 mm and less than or equal to 12 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.2 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.25 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.3 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.35 mm.

6. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 3, characterized in that: The roll gap adjustment strategy includes: when the control interval is greater than 12 mm and less than or equal to 16 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.2 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.25 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.35 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.4 mm.

7. The method for compensating the roller gap caused by steel biting during finishing rolling according to claim 3, characterized in that: The roll gap adjustment strategy includes: when the control interval is greater than 16 mm, before the first finishing rolling stand bites the steel, the roll gap of the first to fourth finishing rolling stands is reduced by 0.25 mm, the roll gap of the fifth finishing rolling stand is reduced by 0.3 mm, the roll gap of the sixth finishing rolling stand is reduced by 0.4 mm, and the roll gap of the seventh finishing rolling stand is reduced by 0.45 mm.

8. The method for compensating the roller gap caused by the impact of steel biting during finishing rolling according to any one of claims 3 to 7, characterized in that: After different roll gap adjustment strategies are executed, the preset time intervals for returning to the roll gap setting value are different.

9. A finishing rolling steel biting impact roll gap compensation system, characterized in that: include: A data acquisition module is used to obtain the roll gap setting value of each finishing mill stand; The roll gap compensation module is used to execute the corresponding finishing mill stand roll gap adjustment strategy according to the strip thickness specification before the first finishing mill stand bites the steel to compensate for the roll gap impact after biting the steel, so that the strip head thickness after finishing rolling meets the preset thickness requirement.

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