An on-line roll grinding control method for free rolling

Abstract

The application relates to an online roll grinding control method for realizing free rolling, which comprises the following steps: step 1, a strip steel roll shifting setting storage module is used for storage; step 2, an online roll grinding roll shifting initial setting calculation module is used for calculation; step 3, a setting sending trigger occasion judgment module is used for judgment; and step 4, an online roll grinding control module is used for control. The scheme is helpful for smoothing and uniformly wearing the roll, and prolongs the rolling mileage of the free rolling.

Description

Technical Field

[0001] This invention relates to a control method, specifically an online grinding roll control method for achieving free rolling, belonging to the field of hot continuous rolling production technology. Background Technology

[0002] To further reduce the production cost of hot strip rolling, direct loading and rolling, separate loading of hot and cold slabs into the furnace, and separate loading of slabs with different heating processes into the furnace are all very effective energy-saving methods. However, due to the random and frequent jumping of different steel grades and specifications during the rolling process, problems such as cross-rolling of different steel grades and specifications and batch width limitations arise. Therefore, hot strip rolling production lines must develop free rolling technology adapted to their own characteristics.

[0003] Free rolling is an ideal state in hot strip rolling production. In actual production, a relatively free rolling method is pursued to improve the capability of mixed cross-rolling. Mixed cross-rolling refers to a production method in which slabs of different widths, thicknesses, and steel grades are cross-charged and cross-rolled. Due to the cross-variation of incoming material widths, controlling the shape and cross-section of the finished strip during mixed cross-rolling is quite difficult. Roll wear caused by rolling narrow strips can easily lead to defects such as edge warping and double-sided waviness in the width direction of the strip. Currently, steel plants both domestically and internationally generally use online roll grinding systems in actual hot strip rolling production to smooth and even out roll wear and extend rolling mileage. However, the initial investment in an online roll grinding system is over one million yuan, and subsequent maintenance by dedicated personnel and investment in spare parts are also required, making it a long-term and continuous investment that increases production costs.

[0004] A novelty search revealed the patent: CN102615560A, titled: "Online Roll Grinding Method for Reverse Width Rolling." This invention discloses an online roll grinding method for achieving reverse width rolling. Based on the maximum strip width in the actual rolling plan and the amount of roll shifting in the work rolls, the effective working area of ​​the rolls is determined. The online roll grinding machine is controlled to grind only the effective area in the center of the roll within a limited rolling time, while the ineffective area that does not contact the strip is not ground. This maximizes the grinding of the roll's through-plate area, resulting in a flat roll shape and ultimately achieving reverse width rolling. This method involves controlling the online roll grinding machine to grind only the effective area in the center of the roll within a limited rolling time, thereby maximizing the grinding of the roll's through-plate area and generating a flat roll shape, ultimately achieving reverse width rolling. It is a method for effective grinding on an online roll grinding machine.

[0005] Patent: CN201420087889.7, Title: A Roll with an Online Grinding Device. This is a utility model patent that discloses a roll with an online grinding device, enabling online grinding without removing the roll from the rolling mill. This solution discloses a roll with an online grinding device, enabling online grinding without removing the roll from the rolling mill. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing an online roller control method for free rolling. This technical solution achieves online roller control through independent programming without adding any hardware equipment. Independent programming represents a one-time labor cost, with zero hardware investment and no subsequent equipment replacement or maintenance costs. The new invention implements an online roller control method by adding four functional modules: a strip roller shifting setting and storage module, an online roller shifting initial setting calculation module, a setting transmission trigger timing judgment module, and an online roller control module. This method is highly operable and effectively extends the rolling mileage not only during free rolling but also during normal rolling.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: an online grinding roll control method for realizing free rolling, the method comprising the following steps:

[0008] Step 1: Store the strip steel shifting roll settings in the storage module.

[0009] Step 2: The initial setting calculation module for the online grinding roller misalignment is used for calculation.

[0010] Step 3: Set the sending trigger timing judgment module to make a judgment.

[0011] Step 4: The online grinding roller control module performs the control.

[0012] As an improvement of the present invention, step 1: the strip roll shifting setting storage module stores the information, specifically as follows: the roll shifting setting positions of the finishing mill F0-F6 stands are recorded and stored in the one-dimensional variable samp.pr_shift[n] of the seven stands, where n represents the seven stands of the finishing mill and is a value between 0 and 6.

[0013] As an improvement of the present invention, step 2: the online grinding roller initial setting calculation module performs the calculation, specifically as follows: the calculation rules of the roller initial setting calculation module follow:

[0014] 1) When samp.pr_shift[n]>0, then cur_shift[n]=shift_limit_min,

[0015] 2) When sample.pr_shift[n] <= 0, then cur_shift[n] = shift_limit_max.

[0016] Where n represents the seven stands of the finishing mill, and n is a value between 0 and 6. shift_limit_min and shift_limit_max are the minimum and maximum stroke limits of the roll shifting in the finishing mill stand.

[0017] As an improvement of the present invention, step 3: the sending trigger timing judgment module is set to make a judgment, specifically as follows: when the production rhythm is slow (Gaptime>60s), the application detects whether there is steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill. If there is no steel, the application sends an online grinding roll setting request to the model. The application sends the requested model-calculated roll setting to L1. When the hot continuous rolling production line is stopped and waiting for material, the operator can manually trigger the request for roll setting. L1 is the first-level basic automation control system.

[0018] As an improvement to the present invention, step 4: the online grinding roller control module performs control, as follows:

[0019] L1 receives the roller setting data calculated by the model and starts the online roller grinding control process:

[0020] (1) First, start the rolling mill F0-F6 stands at high speed.

[0021] (2) At the same time, ensure that the bending rollers of the F0-F6 frame have a 90T balancing force, and then the shifting rollers of the F0-F6 frame reach the set position.

[0022] (3) After applying a static pressure of 300T, release the static pressure.

[0023] (4) The rollers of frames F0-F6 move from the set position to the position of "set position * (-1)".

[0024] (5) After applying a static pressure of 300T, release the static pressure.

[0025] (6) If there is no steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, and the operator has not started changing the rolls, the hopping rolls of stands F0-F6 will continue to move to the set position, and then move to the position of "set position * (-1)".

[0026] (7) After applying a static pressure of 300T, release the static pressure.

[0027] Each time the roll position on stands F0-F6 reaches the set position, a static pressure of 300T is applied and then released. This process is repeated until steel is present in the area from the exit of the last roughing stand to the entrance of the finishing mill, or until the operator triggers a roll change signal. Through these steps, an online roll grinding control method for free rolling is achieved. This scheme helps to smooth and uniform roll wear, extending the rolling mileage of free rolling.

[0028] Compared with the prior art, the present invention has the following advantages: the technical solution has a simple structure and is easy to use. The main advantages of this method are:

[0029] 1) Implement an online grinding roller control method through independent programming without adding any hardware equipment.

[0030] 2) Self-programming involves a one-time investment in labor costs, with zero hardware costs and no subsequent equipment replacement or maintenance costs.

[0031] 3) This method implements an online grinding roll control method by adding four functional modules (strip roll setting and storage module, online grinding roll initial setting calculation module, setting sending trigger timing judgment module, and online grinding roll control module). This method is highly operable.

[0032] 4) It not only effectively extends the rolling mileage of free rolling, but also extends the mileage during normal rolling. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the online grinding roller control process of the present invention. Detailed Implementation

[0034] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0035] Example 1: See Figure 1 An online grinding roll control method for achieving free rolling, the method comprising the following steps:

[0036] Step 1: Store the strip steel shifting roll settings in the storage module.

[0037] Step 2: The initial setting calculation module for the online grinding roller misalignment is used for calculation.

[0038] Step 3: Set the sending trigger timing judgment module to make a judgment.

[0039] Step 4: The online grinding roller control module performs the control.

[0040] Step 1: The strip roll shifting setting storage module stores the information, specifically as follows: Record the roll shifting setting positions of the finishing mill F0-F6 stands, and store them in the one-dimensional variable samp.pr_shift[n] with seven stands, where n represents the seven stands of the finishing mill and is a value between 0 and 6.

[0041] Step 2: The initial setting calculation module for the online grinding roller misalignment is calculated as follows: The calculation rules of the initial setting calculation module for the roller misalignment follow:

[0042] 1. When samp.pr_shift[n]>0, then cur_shift[n]=shift_limit_min,

[0043] 2. When sample.pr_shift[n] <= 0, then cur_shift[n] = shift_limit_max.

[0044] Where n represents the seven stands of the finishing mill, and n is a value between 0 and 6. shift_limit_min and shift_limit_max are the minimum and maximum stroke limits of the roll shifting in the finishing mill stand.

[0045] Step 3: The trigger timing judgment module is set to make a judgment, as follows: When the production rhythm is slow (Gaptime>60s), the application checks whether there is steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill. If there is no steel, the application sends an online grinding roll setting request to the model. The application sends the roll setting calculated by the model to L1. When the hot continuous rolling production line is stopped and waiting for material, the operator can manually trigger the request for roll setting. L1 is the first-level basic automation control system.

[0046] Step 4 involves control via the online grinding roller control module, as detailed below:

[0047] L1 receives the roller setting data calculated by the model and starts the online roller grinding control process:

[0048] (1) First, start the rolling mill F0-F6 stands at high speed.

[0049] (2) At the same time, ensure that the bending rollers of the F0-F6 frame have a 90T balancing force, and then the shifting rollers of the F0-F6 frame reach the set position.

[0050] (3) After applying a static pressure of 300T, release the static pressure.

[0051] (4) The rollers of frames F0-F6 move from the set position to the position of "set position * (-1)".

[0052] (5) After applying a static pressure of 300T, release the static pressure.

[0053] (6) If there is no steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, and the operator has not started changing the rolls, the hopping rolls of stands F0-F6 will continue to move to the set position, and then move to the position of "set position * (-1)".

[0054] (7) After applying a static pressure of 300T, release the static pressure.

[0055] Each time the roll shifting position of stands F0-F6 reaches the set position, a static pressure of 300T must be applied and then released. This process is repeated until steel is present in the area from the exit of the last roughing stand to the entrance of the finishing mill, or until the operator triggers the roll change start signal.

[0056] Through the above steps, an online roller grinding control method for free rolling is achieved. This method helps to smooth and uniform roller wear, and extend the rolling mileage of free rolling.

[0057] Example 2: Taking the free rolling production of Meigang 1422 hot strip mill on June 5, 2023 as an example, an online grinding roll control method for realizing free rolling is applied.

[0058] Step 1: The strip roll setting and storage module records the roll setting positions of the finishing mill stands F0-F6, and stores them in the one-dimensional variable samp.pr_shift[0..6]=[0,-23.75,-25.43,-17.08,-49.99,20.02,-3.60] of the seven stands respectively.

[0059] Step 2: Calculation of the initial setting of the online grinding roll and the initial setting of the rolling roll for frames F0-F6.

[0060] The output of samp.pr_shift[0..6]=[0,-23.75,-25.43,-17.08,-49.99,20.02,-3.60] is [False,False,False,False,False,True,False], according to the following rules:

[0061] 1. When samp.pr_shift[n]>0, then cur_shift[n]=shift_limit_min;

[0062] 2. When samp.pr_shift[n] <= 0, then cur_shift[n] = shift_limit_max.

[0063] In the Meigang 1422 hot strip mill production line, the shift_limit_min and shift_limit_max of the F0 stand are both 0, while the shift_limit_min of the other F1-F6 stands is -95 and the shift_limit_max is 95. Therefore, the calculated initial setting position of the online grinding roll shifting of the finishing mill F0-F6 stands is [0,95,95,95,95,-95,95].

[0064] Step 3: Set the trigger timing judgment module. If the application detects that there is no steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, the application sends an online grinding roll setting request to the model. The application sends the requested model-calculated roll setting [0,95,95,95,95,-95,95] for stands F0-F6 to L1.

[0065] Step 4: Online grinding roller control module,

[0066] L1 received the roll shifting setting data [0, 95, 95, 95, 95, -95, 95]. Initiate online roll grinding control:

[0067] (1) First, start the rolling mill F0-F6 stand with high acceleration, while ensuring that the bending roll of F0-F6 stand has a 90T balancing force.

[0068] (2) The rollers of the F0-F6 frame reach the set position of [0,95,95,95,95,-95,95].

[0069] (3) Release the static pressure after applying a static pressure of 300T.

[0070] (4) The rollers of frame F0-F6 move from the set position to the position of “set position * (-1)”, i.e. [0, -95, -95, -95, -95, 95, -95].

[0071] (5) Release the static pressure after applying a static pressure of 300T.

[0072] (6) If there is no steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, and the operator has not started changing the rolls, the hopping rolls of stands F0-F6 will continue to move to the set position, and then move to the position of “set position * (-1)” [0,95,95,95,95,-95,95].

[0073] (7) Release the static pressure after applying a static pressure of 300T.

[0074] Each time the roll position of the F0-F6 stands reaches the set position, a static pressure of 300T must be applied and then released. This process is repeated until there is steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, or until the operator triggers the start roll change signal.

[0075] Through the above steps, an online roller grinding control method for free rolling is achieved. This new method contributes to the uniformity of roller wear and extends the rolling mileage of free rolling.

[0076] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling online grinding rolls to achieve free rolling, characterized in that, The method includes the following steps: Step 1: Store the strip steel shifting roll settings in the storage module. Step 2: The initial setting calculation module for the online grinding roller misalignment is used for calculation. Step 3: Set the sending trigger timing judgment module to make a judgment. Step 4: The online grinding roller control module performs the control; Specifically, step 1 is as follows: record the roll shifting positions of the finishing mill stands F0-F6, and store them in the one-dimensional variable samp.pr_shift[n] with seven stands, where n represents the seven finishing mill stands and is a value between 0 and 6; Step 2 is as follows: The calculation rules of the initial setting calculation module for the skewed roller follow the following: 1) When samp.pr_shift[n]>0, then cur_shift[n]=shift_limit_min, 2) When sample.pr_shift[n] <= 0, then cur_shift[n] = shift_limit_max. Where n represents the seven stands of the finishing mill, and n is a value between 0 and 6. shift_limit_min and shift_limit_max are the minimum and maximum stroke limits of the roll shifting in the finishing mill stand. Step 3 is as follows: When the production pace is slow, the application checks whether there is steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill. If there is no steel, the application sends an online grinding roll setting request to the model. The application sends the roll setting calculated by the model to L1. When the hot continuous rolling production line is stopped and waiting for material, the operator can manually trigger the request to set the roll setting. L1 is the first-level basic automation control system. Step 4 is as follows: L1 receives the roller setting data calculated by the model and starts the online roller grinding control process: (1) First, start the rolling mill F0-F6 stands at high speed. (2) At the same time, ensure that the bending rollers of the F0-F6 frame have a 90T balancing force, and then the shifting rollers of the F0-F6 frame reach the set position. (3) After applying a static pressure of 300T, release the static pressure. (4) The rollers of frames F0-F6 move from the set position to the position of "set position * (-1)". (5) After applying a static pressure of 300T, release the static pressure. (6) If there is no steel in the area from the exit of the last stand of the roughing mill to the entrance of the finishing mill, and the operator has not started changing the rolls, the skew rolls of stands F0-F6 will continue to move to the set position, and then move to the position of "set position * (-1)". (7) After applying a static pressure of 300T, release the static pressure. Each time the roll shifting position of stands F0-F6 reaches the set position, a static pressure of 300T must be applied and then released. This process is repeated until steel is present in the area from the exit of the last roughing stand to the entrance of the finishing mill, or until the operator triggers the roll change start signal. Through the above steps, an online grinding roll control method for achieving free rolling is realized.

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