A method for rolling a plate by vertical roll
By adopting a widening stage, setting the roll gap for odd and even passes, and adjusting the short stroke during the rolling process of medium and heavy plates, combined with fixed-width rolling, the problems of bulging and fishtailing of steel plates in the rolling process of medium and heavy plates were solved, thereby improving the yield and quality of steel plates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
- Filing Date
- 2024-04-09
- Publication Date
- 2026-07-21
AI Technical Summary
During the rolling process of medium and heavy plates, steel plates are prone to bulging and fishtail shapes, which leads to a decrease in yield. Existing technologies make it difficult to achieve precise vertical roll gap control and rapid positioning.
A vertical roll rolling method is adopted, which achieves rectangular rolling of steel plates by setting different roll gaps in the widening stage, odd and even passes, and short stroke adjustment, combined with fixed width rolling.
It effectively improves the shape of medium and heavy steel plates, reduces shearing loss, increases yield, reduces trimming amount and fishtail shape, and improves steel plate quality.
Smart Images
Figure CN118218395B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metallurgical technology, and in particular to a vertical roll rolling method for achieving rectangularization of medium-thick plates. Background Technology
[0002] In the hot rolling industry of iron and steel metallurgy, vertical rolls are important equipment for achieving rectangular rolling of steel plates and improving steel plate yield. With the design improvement of steel plate yield, it is required that the width of the intermediate billet after roughing mill rolling is precisely controlled in each rolling stage of the attached vertical rolls to obtain a more perfect rectangular plate shape in order to meet the requirements of improving steel plate yield.
[0003] Medium-thick plate planar shape control technology is also known as medium-thick plate rectangular rolling technology. Thick plate rolling involves first widening the slab and then extending it in the length direction. According to the law of least resistance, when a metal undergoes plastic deformation under external force, its internal particles always flow along the direction of least resistance. Therefore, during medium-thick plate rolling, due to the characteristics of metal plastic deformation, uneven deformation occurs along the width direction of the rolled piece, especially noticeable at the beginning and end of the slab. Consequently, the rolled steel plate not only deviates from a rectangle but also exhibits uneven width extension along its length. When the width-to-width ratio is large (e.g., greater than 1.4), the steel plate's sides are drum-shaped, while when the width-to-width ratio is small (e.g., less than 1.4), the sides are negatively drum-shaped. The head and tail shapes of the steel plate are uneven, resembling arcs or fishtails, resulting in significant losses from head, tail, and edge trimming, thus reducing the yield.
[0004] Therefore, a reliable and easy-to-implement method for controlling the roll gap of vertical rolls is needed to ensure the accuracy of roll gap control and the speed of roll gap positioning in the vertical roll rolling process. Summary of the Invention
[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a vertical roll rolling method for realizing the rectangularization of medium and heavy plates, which can solve the problems of steel plate bulging and fishtailing that occur during the rolling of medium and heavy plates.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a vertical roll rolling method for achieving rectangularization of medium-thick plates, comprising the following specific methods.
[0007] Vertical rollers are used in the S1 widening stage.
[0008] When the medium-thick steel plate is in the widening stage of rolling (between the first and second rolling), if the current pass is the first rolling pass, the "widening stage" setting will be activated and the function of using vertical rolls in the widening stage will be automatically activated.
[0009] After that, regardless of whether the rolling passes are odd or even, vertical rollers are used to roll the steel plate at the head and tail during the widening stage until the second steel transfer signal arrives, at which point the "widening stage" is reset, thus completing the function of using vertical rollers during the widening stage.
[0010] S2 odd-numbered passes use vertical rollers
[0011] The vertical rolls attached to the roughing mill, according to the traditional vertical roll rolling process, are only used in the even-numbered passes of the longitudinal rolling stage of medium and heavy steel plates to squeeze and roll the edges of the steel plates.
[0012] Sometimes, in order to ensure the performance of the steel plate, the number of vertical roll edge rolling passes calculated by the L2 model is relatively limited. Under this process, although the steel plate is rolled by vertical roll edge extrusion, if the horizontal mill reduction is set improperly, whether too large or too small, the steel plate will still have a bulging or negative bulging shape, and it is easy to cause asymmetry in the head and tail of the fishtail, which has a very limited effect on controlling the planar shape of the steel plate.
[0013] The new method of using vertical rolls in odd-numbered passes was developed to compensate for the defects of traditional vertical roll rolling process. In order to avoid the steel plate being easily clamped when using vertical rolls for edge rolling in the last odd-numbered passes of the rolling process when the horizontal mill passes empty and the steel plate thickness is small, the system will automatically judge that when the steel plate thickness is less than 75mm, this rolling method will be stopped and the vertical rolls will be opened to the safety roll gap of width +300mm.
[0014] S3 fixed width rolling
[0015] In traditional vertical roll rolling processes, the roll gap calculated by the L2 (process automation) model cannot guarantee the most economical trimming margin for steel plates. Developing a new fixed-width rolling method in the last even-numbered pass of vertical roll rolling can effectively guarantee the trimming margin of steel plates and improve the yield.
[0016] In the new method of fixed-width rolling, the roll gap of the vertical roll is set according to the contract width of the medium-thick steel plate. This width can be calculated from the L2 model or manually entered by the operator in the L2 interface. After calculation in the program, the effective roll gap of the last even-numbered pass of the vertical roll is automatically calculated. Rolling is carried out with this roll gap to ensure the trimming margin of the steel plate and improve the yield.
[0017] Preferably, after the "widening stage" begins, the roughing mill's automatic control system will perform automatic centering of the side guide plates to center the steel plate and measure its width. The steel plate width measured by the side guide plates will be used as the basis for calculating the vertical roll gap in this stage. The formula for calculating the vertical roll gap in this stage is as follows:
[0018] GapOdd=Wact–(n+1)*a / 2–(n-1)*b / 2
[0019] GapEven = Wact - n*a / 2 – n*b / 2
[0020] In the formula, GapOdd (mm) is the set roll gap for odd-numbered vertical rolls, and GapEven (mm) is the set roll gap for even-numbered vertical rolls; a (mm) and b (mm) are the set reduction constants; n = 1, 2, 3..., is the current actual number of passes in the roughing mill; Wact (mm) is the actual width of the steel plate measured after the mill side guide plate is aligned during the widening stage.
[0021] Preferably, during the widening stage, when vertical rolls are used to roll the head and tail, the resistance of the metal along the longitudinal direction of the billet is greater than the resistance of the metal flowing towards the edge. Therefore, during the rolling process, the metal mainly flows towards the head and tail edges of the billet to compensate for the poor planar shape formed during the widening process and achieve rectangular rolling.
[0022] Preferably, the reduction and roll gap calculation for odd-numbered vertical rolls are based on the actual roll gap of the previous even-numbered vertical roll. In this stage, the roll gap calculation formula for odd-numbered vertical rolls is as follows:
[0023] GapOdd = GapEven_act-c
[0024] In the formula, GapEven_act(mm) is the actual rolling gap of the vertical rolls in even-numbered passes, and GapOdd(mm) is the set gap of the vertical rolls in odd-numbered passes, with a corresponding reduction amount of c(mm).
[0025] To achieve a more perfect dog-bone shape, this invention also developed a short-stroke method for odd-numbered passes of vertical rollers. The short stroke amount is determined according to the thickness of the steel plate, and the setting range is 10mm to 15mm. This method greatly improves the shape of the steel plate and suppresses negative or positive bulging of the steel plate.
[0026] Preferably, the rolling method using vertical rolls in the widening stage is illustrated by the example of medium and heavy plate production. A certain steel plate has a total of 9 passes in the roughing mill. The first pass is the first transfer pass, and the fourth pass is the second transfer pass.
[0027] The first pass is set to the "broadening stage" and the rolling process ends at the fourth pass, at which the "broadening stage" is reset. In this example, the first to third passes are the "broadening stage". The fourth pass is not part of the broadening stage since it has been reset.
[0028] The actual measured width Wact of the steel plate obtained after centering the side guide plate of the first roughing mill is 3800mm. The corresponding reduction a is set to 15mm. Therefore, according to... Figure 1 The flowchart shown indicates that the first and third passes are odd-numbered passes in the widening phase, and the second pass is an even-numbered pass in the widening phase.
[0029] According to the formula GapOdd=Wact–(n+1)*a / 2–(n-1)*b / 2, the roll gap for the first vertical roll is calculated as Gapodd=3800-(1+1)*15 / 2-(1-1)*10 / 2=3800-15=3785mm, and the roll gap for the third vertical roll is calculated as Gapodd=3800-(3+1)*15 / 2-(3-1)*10 / 2=3800-30-10=3760mm; according to the formula GapEven=Wact-n*(a+b) / 2, the roll gap for the second vertical roll is calculated as Gapodd=3800-2*(10+15) / 2=3775mm. The roll gaps for the first, second, and third passes of the widening stage are set to 3785mm, 3775mm, and 3760mm, respectively.
[0030] Preferably, the rolling method using vertical rolls in the odd-numbered passes of the longitudinal rolling stage is used to avoid the steel plate being easily clamped when the horizontal mill passes empty in the last odd-numbered passes of the rolling process and the steel plate thickness is small. The system will automatically judge that when the thickness of the steel plate in the current pass is less than 75mm, this rolling method will be stopped and the vertical rolls will be opened to the safety roll gap of width +300mm.
[0031] Taking the steel plate listed in "Rolling Method Using Vertical Rollers in the Widening Stage" as an example, a certain steel plate has a total of 9 passes in the roughing mill. The first pass is the first transfer pass, and the fourth pass is the second transfer pass.
[0032] Since the fourth pass is the second steel transfer, the "widening stage" has ended, and the rolling process has entered the "longitudinal rolling stage." According to the traditional vertical roll rolling method, the 4th, 6th, and 8th passes are the traditional vertical roll passes. Assuming the roll gaps calculated by the vertical roll model for the 4th, 6th, and 8th passes are 2800mm, 2765mm, and 2745mm respectively, and the reduction constant c is set to 10mm, based on GapOdd = GapEven_act - c, the automatic vertical roll control system can automatically calculate the roll gaps for the 5th, 7th, and 9th passes as 2790mm, 2755mm, and 2735mm respectively. Therefore, the set roll gaps for the vertical rolls in the longitudinal rolling stage for the 4th, 5th, 6th, 7th, 8th, and 9th passes are 2800mm, 2790mm, 2765mm, 2755mm, 2745mm, and 2735mm respectively. In traditional vertical roll passes, after the 4th, 6th, and 8th passes are rolled by vertical rolls, when the steel plate enters the horizontal roughing mill, a certain degree of width expansion will occur. Therefore, it is very necessary to use vertical rolls again to roll the edges of the steel plate in the odd-numbered passes after each traditional vertical roll pass, which can achieve a very good effect on planar shape control.
[0033] In the 5th, 7th, and 9th passes of the aforementioned steel plate, an automatic short-stroke function was also designed to achieve dog-bone rolling of the steel plate. For example... Figure 3 As shown, in the rolling direction of the steel plate, the vertical roll gap is dynamically adjusted according to the set short stroke parameter of 10mm. In the figure, "1" is the given short stroke curve of the vertical roll gap, and "2" is the actual short stroke curve of the vertical roll gap.
[0034] If, during the roughing mill rolling process, the steel plate thickness is less than 75mm in any actual pass, this invention will immediately make a judgment, stop using this method, set the vertical roll gap to the steel plate width + 300mm, and drive the mechanical and hydraulic pressing systems of the vertical roll to open the vertical roll gap to this safe gap, preventing the steel plate from being too thin and being clamped by the vertical roll, thus preventing a shutdown accident.
[0035] Preferably, the fixed width rolling method still takes the steel plate mentioned above as an example. The "fixed width rolling" of the present invention will be applied to the last conventional vertical roll pass of the steel plate, that is, the 8th pass.
[0036] At this point, if the operator manually inputs the target contract width of the steel plate as 2720mm on the L2 interface of the rolling mill, the vertical roll automation system will convert the steel plate from cold to hot state (converted by a coefficient of 1.013), and the calculated 8th roll gap will be 2755.36mm. Correspondingly, the 9th roll gap will still be calculated as 2735mm according to the formula GapOdd=GapEven_act-c.
[0037] This fixed-width rolling method is an important supplement to the "rolling method using vertical rolls in the widening stage" and the "rolling method using vertical rolls in odd-numbered passes in the longitudinal rolling stage". It achieves the final effective width control of the steel plate to ensure the minimum trimming margin of the steel plate, thereby improving the yield of the steel plate.
[0038] Compared with the prior art, the beneficial effects of the present invention are:
[0039] (1) This invention, based on the law of minimum resistance and the law of constant volume, is a novel method for controlling the planar shape of steel plates. It effectively improves the shape of medium-thick steel plates, reduces shear loss, improves the quality of the head, tail, and edges, and increases the overall yield of the steel plates. This invention utilizes vertical rolls in both the slab widening stage and the odd and even passes of the longitudinal rolling stage during the roughing process. The setting and positioning of the roll gap at each stage are fully automated by the automatic control system, making operation simple and maintenance easy.
[0040] (2) The vertical roll rolling method for realizing the rectangularization of medium and heavy plates reduces the steel plate trimming amount from the original shear line trimming amount of 70-100mm to 30-50mm, which improves the overall yield by more than 1% to 1.5%, and also greatly reduces the unplanned width caused by the large edge bulge; 2) The head and tail shape of the steel plate rolling has also been significantly improved, and the fishtail shape has been better controlled. The actual head and tail trimming amount has been reduced from the previous 300-500mm to the current 100-300mm, reducing the cutting loss by 40% to 60%, greatly reducing the unplanned length of the steel plate, and improving the steel plate yield by about 1%.
[0041] (3) The vertical roll rolling method for realizing the rectangularization of medium and thick plates is an important supplement to the "rolling method using vertical rolls in the widening stage" and the "rolling method using vertical rolls in odd-numbered passes in the longitudinal rolling stage". It realizes the final effective width control of the steel plate to ensure the minimum cutting margin of the steel plate, thereby improving the yield of the steel plate.
[0042] (4) This vertical roll rolling method for achieving rectangularization of medium-thick plates requires only setting the corresponding reduction amounts a and b on the HMI. The entire vertical roll rolling process and roll gap calculation are completed automatically, requiring no further operator intervention, making it truly simple and easy to implement. To better eliminate the bulging or fishtail shape of the steel plate, the width of the roughing mill side guide plate needs to be periodically calibrated to ensure the accuracy of the steel plate width measurement. Appropriately setting the reduction rate of the roughing horizontal mill can obtain more widening passes to achieve a more perfect steel plate planar shape. Attached Figure Description
[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0044] Figure 1 Flowchart of vertical rollers used in the expansion stage of this invention;
[0045] Figure 2 This is a flowchart illustrating the use of vertical rollers in odd-numbered passes according to the present invention.
[0046] Figure 3 This is a short stroke curve of the odd-numbered vertical roll gap in this invention. Detailed Implementation
[0047] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.
[0048] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 limiting this invention.
[0049] In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0050] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.
[0051] A vertical roll rolling method for achieving rectangularization of medium-thick plates includes the following specific methods.
[0052] Vertical rollers are used in the S1 widening stage.
[0053] When the medium-thick steel plate is in the widening stage of rolling (between the first and second rolling), if the current pass is the first rolling pass, the "widening stage" setting will be activated and the function of using vertical rolls in the widening stage will be automatically activated.
[0054] After that, regardless of whether the rolling passes are odd or even, vertical rollers are used to roll the steel plate at the beginning and end during the widening stage until the second steel transfer signal arrives, at which point the "widening stage" is reset, thus completing the function of using vertical rollers during the widening stage.
[0055] After the "width expansion stage" begins, the roughing mill's automatic control system will perform automatic centering operations on the side guides to center the steel plate and measure its width. The steel plate width measured by the side guides will be used as the basis for calculating the vertical roll gap in this stage. The formula for calculating the vertical roll gap in this stage is as follows:
[0056] GapOdd=Wact–(n+1)*a / 2–(n-1)*b / 2
[0057] GapEven = Wact - n*a / 2 – n*b / 2
[0058] In the formula, GapOdd (mm) is the set roll gap for odd-numbered vertical rolls, and GapEven (mm) is the set roll gap for even-numbered vertical rolls; a (mm) and b (mm) are the set reduction constants; n = 1, 2, 3..., is the current actual number of passes in the roughing mill; Wact (mm) is the actual width of the steel plate measured after the mill side guide plate is aligned during the widening stage.
[0059] During the widening stage, when vertical rolls are used to roll the head and tail, the resistance of the metal along the longitudinal direction of the billet is greater than the resistance of the metal flowing towards the edge. Therefore, during the rolling process, the metal mainly flows towards the head and tail edges of the billet to compensate for the poor planar shape formed during the widening process and achieve rectangular rolling.
[0060] This invention only requires setting the corresponding reduction amounts 'a' and 'b' on the HMI; the entire vertical roll rolling process and roll gap calculation are completed automatically, requiring no further operator intervention, making it truly simple and easy to implement. To better eliminate the bulging or fishtail shape of the steel plate, the width of the roughing mill side guide plates needs to be periodically calibrated to ensure the accuracy of the steel plate width measurement. Appropriately setting the reduction rate of the roughing horizontal mill can obtain more widening passes, thereby achieving a more perfect steel plate planar shape.
[0061] S2 odd-numbered passes use vertical rollers
[0062] The vertical rolls attached to the roughing mill, according to the traditional vertical roll rolling process, are only used in the even-numbered passes of the longitudinal rolling stage of medium and heavy steel plates to squeeze and roll the edges of the steel plates.
[0063] Sometimes, in order to ensure the performance of the steel plate, the number of vertical roll edge rolling passes calculated by the L2 model is relatively limited. Under this process, although the steel plate is edge rolled by vertical rolls, if the reduction of the horizontal mill is not set properly, whether too large or too small, the steel plate will still have a bulging or negative bulging shape, and it is easy to cause asymmetry in the head and tail of the fishtail, which has a very limited effect on controlling the planar shape of the steel plate.
[0064] The new method of using vertical rolls in odd-numbered passes was developed to compensate for the defects of traditional vertical roll rolling process. In order to avoid the steel plate being easily clamped when using vertical rolls for edge rolling in the last odd-numbered passes of the rolling process when the horizontal mill passes empty and the steel plate thickness is small, the system will automatically judge that when the steel plate thickness is less than 75mm, this rolling method will be stopped and the vertical rolls will be opened to the safety roll gap of width +300mm.
[0065] The reduction and roll gap calculation for odd-numbered vertical rolls are based on the actual roll gap of the previous even-numbered vertical roll. In this stage, the roll gap calculation formula for odd-numbered vertical rolls is as follows:
[0066] GapOdd = GapEven_act-c
[0067] In the formula, GapEven_act(mm) is the actual rolling gap of the vertical rolls in even-numbered passes, and GapOdd(mm) is the set gap of the vertical rolls in odd-numbered passes, with a corresponding reduction amount of c(mm).
[0068] To achieve a more perfect dog-bone shape, this invention also developed a short-stroke method for odd-numbered passes of vertical rollers. The short stroke amount is determined according to the thickness of the steel plate, and the setting range is 10mm to 15mm. This method greatly improves the shape of the steel plate and suppresses negative or positive bulging of the steel plate.
[0069] S3 fixed width rolling
[0070] In traditional vertical roll rolling processes, the roll gap calculated by the L2 (process automation) model cannot guarantee the most economical trimming margin for steel plates. Developing a new fixed-width rolling method in the last even-numbered pass of vertical roll rolling can effectively guarantee the trimming margin of steel plates and improve the yield.
[0071] In the new method of fixed-width rolling, the roll gap of the vertical roll is set according to the contract width of the medium-thick steel plate. This width can be calculated from the L2 model or manually entered by the operator in the L2 interface. After calculation in the program, the effective roll gap of the last even-numbered pass of the vertical roll is automatically calculated. Rolling is carried out with this roll gap to ensure the trimming margin of the steel plate and improve the yield.
[0072] Rolling method using vertical rolls during the widening stage Figure 1 As shown, taking the production of medium and heavy plates as an example, a certain steel plate goes through a total of 9 passes in the roughing mill. The first pass is the first transfer pass, and the fourth pass is the second transfer pass.
[0073] The first pass is set to the "broadening stage" and the rolling process continues until the fourth pass, at which point the "broadening stage" is reset. In this example, the first to third passes are the "broadening stage", while the fourth pass, having already been reset, is not part of the broadening stage.
[0074] The actual measured width Wact of the steel plate obtained after centering the side guide plate of the first roughing mill is 3800mm. The corresponding reduction a is set to 15mm. Therefore, according to... Figure 1 The flowchart shown indicates that the first and third passes are odd-numbered passes in the widening phase, while the second pass is an even-numbered pass in the widening phase.
[0075] According to the formula GapOdd=Wact–(n+1)*a / 2–(n-1)*b / 2, the roll gap for the first vertical roll is calculated as Gapodd=3800-(1+1)*15 / 2-(1-1)*10 / 2=3800-15=3785mm, and the roll gap for the third vertical roll is calculated as Gapodd=3800-(3+1)*15 / 2-(3-1)*10 / 2=3800-30-10=3760mm; according to the formula GapEven=Wact-n*(a+b) / 2, the roll gap for the second vertical roll is calculated as Gapodd=3800-2*(10+15) / 2=3775mm. The roll gaps for the first, second, and third passes of the widening stage are set to 3785mm, 3775mm, and 3760mm, respectively.
[0076] This invention only requires setting the corresponding reduction constants a and b on the HMI, and the entire vertical roll rolling process and roll gap calculation are completed automatically without any other operator intervention, making it truly simple and easy to implement.
[0077] In the longitudinal rolling stage, odd-numbered passes use vertical rolls for rolling methods, such as... Figure 2 As shown, in order to avoid the steel plate being easily clamped when using vertical rolls for edge rolling in the last odd-numbered passes of the rolling process with the horizontal mill empty and the steel plate thickness being small, the system will automatically judge that when the thickness of the steel plate in the current pass is less than 75mm, this rolling method will be stopped and the vertical rolls will be opened to the safety roll gap of width +300mm.
[0078] Taking the steel plate listed in "Rolling Method Using Vertical Rollers in the Widening Stage" as an example, a certain steel plate has a total of 9 passes in the roughing mill. The first pass is the first transfer pass, and the fourth pass is the second transfer pass.
[0079] Since the fourth pass is the second steel transfer, the "widening stage" has ended, and the rolling process has entered the "longitudinal rolling stage." According to the traditional vertical roll rolling method, the 4th, 6th, and 8th passes are the traditional vertical roll passes. Assuming the roll gaps calculated by the vertical roll model for the 4th, 6th, and 8th passes are 2800mm, 2765mm, and 2745mm respectively, and the reduction constant c is set to 10mm, based on GapOdd = GapEven_act - c, the automatic vertical roll control system can automatically calculate the roll gaps for the 5th, 7th, and 9th passes as 2790mm, 2755mm, and 2735mm respectively. Therefore, the set roll gaps for the vertical rolls in the longitudinal rolling stage for the 4th, 5th, 6th, 7th, 8th, and 9th passes are 2800mm, 2790mm, 2765mm, 2755mm, 2745mm, and 2735mm respectively. In traditional vertical roll passes, after the 4th, 6th, and 8th passes are rolled by vertical rolls, a certain degree of width expansion occurs when the steel plate enters the horizontal roughing mill. Therefore, it is very necessary to use vertical rolls again to roll the edges of the steel plate in the odd-numbered passes after each traditional vertical roll pass, which can achieve a very good effect in controlling the planar shape.
[0080] In the 5th, 7th, and 9th passes of the aforementioned steel plate, an automatic short-stroke function was also designed to achieve dog-bone rolling of the steel plate. For example... Figure 3 As shown, in the rolling direction of the steel plate, the vertical roll gap is dynamically adjusted according to the set short stroke parameter of 10mm. In the figure, "1" is the given short stroke curve of the vertical roll gap, and "2" is the actual short stroke curve of the vertical roll gap.
[0081] If, during the roughing mill rolling process, the steel plate thickness is less than 75mm in any actual pass, this invention will immediately make a judgment, stop using this method, set the vertical roll gap to the steel plate width + 300mm, and drive the mechanical and hydraulic pressing systems of the vertical roll to open the vertical roll gap to this safe gap, preventing the steel plate from being too thin and being clamped by the vertical roll, thus preventing a shutdown accident.
[0082] Taking the steel plate mentioned above as an example, the "fixed width rolling" of the present invention will be applied to the last conventional vertical roll pass of the steel plate, namely the 8th pass.
[0083] At this point, if the operator manually inputs the target contract width of the steel plate as 2720mm on the L2 interface of the rolling mill, the vertical roll automation system will convert the steel plate from cold to hot state (converted by a coefficient of 1.013), and the calculated 8th roll gap will be 2755.36mm. Correspondingly, the 9th roll gap will still be calculated as 2735mm according to the formula GapOdd=GapEven_act-c.
[0084] This fixed-width rolling method is an important supplement to the "rolling method using vertical rolls in the widening stage" and the "rolling method using vertical rolls in odd-numbered passes in the longitudinal rolling stage". It achieves the final effective width control of the steel plate to ensure the minimum trimming margin of the steel plate, thereby improving the yield of the steel plate.
[0085] Furthermore, this invention proposes a novel method for controlling the planar shape of steel plates based on the law of least resistance and the law of constant volume. It effectively improves the shape of medium-thick steel plates, reduces shearing losses, enhances the quality of the head, tail, and edges, and increases the overall yield of the steel plates. This invention achieves the use of vertical rolls in both the slab widening stage and the odd and even passes of the longitudinal rolling stage during roughing. The setting and positioning of the roll gaps at each stage are fully automated by an automatic control system, making operation simple and maintenance easy.
[0086] Furthermore, the steel plate trimming amount of the present invention is reduced from 70-100mm at the original shear line trimming level to 30-50mm, which improves the overall yield by more than 1% to 1.5%, and also greatly reduces the unplanned width caused by the large edge bulge; 2) The head and tail shape of the steel plate rolling is also significantly improved, the fishtail shape is better controlled, and the actual head and tail trimming amount is reduced from 300-500mm to 100-300mm, reducing cutting loss by 40% to 60%, greatly reducing the unplanned length of the steel plate, and improving the steel plate yield by about 1%.
[0087] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. A vertical roll rolling method for achieving rectangularization of medium-thick plates, characterized in that: Including the following specific methods Vertical rollers are used in the S1 widening stage. When the medium-thick steel plate is in the widening stage of rolling, between the first and second steel transfers, if the current pass is the first steel transfer pass, the widening stage is set and the function of using vertical rolls in the widening stage is automatically activated. After that, regardless of whether the rolling passes are odd or even, vertical rollers are used to roll the steel plate at the beginning and end during the widening stage until the second steel transfer signal arrives, at which point the widening stage is reset, thus completing the function of using vertical rollers during the widening stage. S2 odd-numbered passes use vertical rollers The reduction and roll gap calculation for odd-numbered vertical rolls are based on the actual roll gap of the previous even-numbered vertical roll. The formula for calculating the roll gap for odd-numbered vertical rolls is as follows: GapOdd=GapEven_act-c; In the formula, GapEven_act is the actual roll gap of the even-numbered vertical rolls, in millimeters; GapOdd is the set roll gap of the odd-numbered vertical rolls, in millimeters; and the corresponding reduction is c, in millimeters. In the length rolling direction of the steel plate, the roll gap of the vertical roll is dynamically adjusted according to the set short stroke amount, which is determined according to the thickness of the steel plate and is set in the range of 10mm to 15mm. The system will automatically determine whether to stop using this rolling method when the steel plate thickness is less than 75mm, and will open the vertical rolls to the safety roll gap width + 300mm. S3 fixed width rolling In the new method of fixed-width rolling, the roll gap of the vertical roll is set according to the contract width of the medium-thick steel plate. The contract width is calculated from the L2 model or manually entered by the operator in the L2 interface. After calculation in the program, the effective roll gap of the last even-numbered pass of the vertical roll is automatically calculated, and rolling is carried out with this roll gap.
2. The vertical roll rolling method for achieving rectangularization of medium-thick plates according to claim 1, characterized in that: After the widening stage begins, the roughing mill's automatic control system will perform automatic centering operations on the side guides to center the steel plate and measure its width. The steel plate width measured by the side guides will be used as the basis for calculating the vertical roll gap during the widening stage. The vertical roll gap calculation formula is as follows: GapOdd=Wact – (n+1)*a / 2 – (n-1)*b / 2; GapEven=Wact - n*a / 2 –n*b / 2; In the formula, GapOdd is the set roll gap for odd-numbered vertical rolls, in millimeters; GapEven is the set roll gap for even-numbered vertical rolls, in millimeters; a and b are the set reduction amounts, in millimeters; n=1,2,3……, is the current actual number of passes in the roughing mill; Wact is the actual width of the steel plate measured after centering of the mill side guide plate during the widening stage, in millimeters.
3. The vertical roll rolling method for achieving rectangularization of medium-thick plates according to claim 1, characterized in that: During the widening stage, when vertical rolls are used to roll the head and tail, the resistance of the metal along the longitudinal direction of the billet is greater than the resistance of the metal flowing towards the edge. Therefore, during the rolling process, the metal mainly flows towards the head and tail edges of the billet to compensate for the poor planar shape formed during the widening process and achieve rectangular rolling.