A Stepped Temperature-Waiting Production Method and System Based on a Single-Frame Wide and Thick Plate Rolling Line

Abstract

This invention provides a method and system for stepped warm-up production of thick plate rolling mills based on a single-stand mill, relating to the field of hot-rolled thick plate technology in the metallurgical industry. It aims to improve the problem of mill idling waiting time during batch rolling, which affects the rolling rhythm. The stepped warm-up production method based on a single-stand thick plate rolling mill includes obtaining the warming time of the intermediate slab of the first slab; batch rolling a preset number of slabs based on the warming time of the intermediate slab of the first slab; and controlling the warming thickness of the batch-rolled slabs based on the warming time of the intermediate slab of the first slab. The system includes a controller for executing the above method. By selecting the number of slabs to be batch-rolled based on the warming time of the intermediate slab of the first slab, and then controlling the warming thickness of the batch-rolled slabs based on the warming time of the intermediate slab of the first slab, the idle waiting time of the mill is reduced, and the rolling efficiency and rhythm are improved.

Description

Technical Field

[0001] This invention relates to the field of hot-rolled thick plates in the metallurgical industry, and more specifically, to a method and system for stepped temperature-controlled production of thick plates on a single-stand rolling mill. Background Technology

[0002] For a steel plant, output is a crucial economic indicator, and every steel plant strives to maximize it by every possible means. Under the same conditions, increasing output has a significant impact on reducing costs, minimizing consumption, and improving efficiency.

[0003] During production, it was found that steel plates requiring temperature-controlled rolling often experience idling while waiting for the intermediate billet to reach the desired temperature. Reasonably reducing or eliminating this idling time can significantly improve the rolling pace, thereby increasing output. The more steel plates requiring controlled rolling, the better the improvement. Taking a certain steel heavy plate plant as an example, specialty steels and low-alloy steels requiring temperature-controlled rolling account for over 60% of the total monthly output, indicating a high proportion of steel plates requiring controlled rolling. Summary of the Invention

[0004] The present invention aims to provide, for example, a stepped waiting-for-temperature production method based on a single-stand wide and thick plate rolling line, which can improve the problem of idling waiting time of the rolling mill during batch rolling, which affects the rolling rhythm.

[0005] The present invention also aims to provide a stepped waiting temperature production system based on a single-stand wide and thick plate rolling line, which can improve the problem of idling waiting time of the rolling mill during batch rolling, which affects the rolling rhythm.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] An embodiment of the present invention provides a stepped temperature-controlled production method based on a single-stand wide and thick plate rolling line, wherein the intermediate slab temperature-controlled time of the first slab is obtained; a preset number of slabs are batch rolled according to the intermediate slab temperature-controlled time of the first slab; and the temperature-controlled thickness of the batch rolled slabs is controlled according to the intermediate slab temperature-controlled time of the first slab.

[0008] In addition, the stepped temperature-controlled production method based on a single-stand wide and thick plate rolling line provided in the embodiments of the present invention may also have the following additional technical features:

[0009] Optionally, the step of batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab includes:

[0010] In 180s≦ When t≦260s, the preset number of blocks for batch rolling is N=2;

[0011] exist When t ≥ 300s, the preset number of blocks N for batch rolling is ≥ 3;

[0012] in, t is the waiting time between the first slab reaching the intermediate slab thickness and the final rolling temperature, s is the time unit in seconds, and N is the preset number of slabs to be rolled in batches.

[0013] Optionally, the step of batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab further includes:

[0014] When N≥3, the waiting time of the first slab when the nth slab is produced is used as the reference. t1 controls the output of steel in batch rolling.

[0015] Optionally, when N≥3, the step is based on the waiting time of the first slab when the nth slab is produced. t1, the steps for controlling the tapping of steel in batch rolling include:

[0016] When N≥3, if If t1 ≥ 330S, then steel will be tapped; t1≦280S, steel tapping ends;

[0017] Where N is the preset number of blocks to be batch rolled. t1 is the waiting time of the first slab when the nth slab is produced. t1.

[0018] Optionally, the step of batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab further includes:

[0019] When N≥3; control te- t0 = 90~120s;

[0020] in, te is the waiting time for the nth roughing stage to be completed. t0 is the waiting time for the (n-1)th block to reach the desired temperature.

[0021] Optionally, the step of controlling the heating thickness of the batch-rolled slabs based on the heating time of the intermediate slab of the first slab includes:

[0022] In 180s≦ When t≦260s, e2=(e1-(5mm~15mm);

[0023] Where e1 is the thickness of the first slab to be heated, and e2 is the thickness of the second slab to be heated.

[0024] Optionally, the step of controlling the heating thickness of the batch-rolled slabs based on the heating time of the intermediate slab of the first slab includes:

[0025] exist When t ≥ 300s, E2 = E1; E3 = E1 - 5mm; En = E(n-1) - (0 ~ 10mm);

[0026] En is the thickness to be heated for the nth slab, and E(n-1) is the thickness to be heated for the (n-1)th slab.

[0027] Optionally, the calculation formula for the step of obtaining the intermediate billet waiting time of the first slab includes: Wherein, the steel plate density ρ = 7800 kg / m³, the steel plate thickness e, the average isobaric specific heat capacity Cp during the isobaric process, the slab initial rolling temperature T1, the second-stage intermediate slab initial rolling temperature T2, and the heat flux density q on the surface of the rolled piece.

[0028] Optionally, the step of batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab further includes:

[0029] In 260s When t < 300s, the preset number of blocks for batch rolling is N = 2, and e2 = (e1 - (5mm ~ 15mm)).

[0030] in, t is the thickness of the first slab before it is rolled to the intermediate slab, e1 is the thickness of the first slab before it is heated, and e2 is the thickness of the second slab before it is heated.

[0031] An embodiment of the present invention also provides a stepped temperature-controlled production system based on a single-stand thick plate rolling line. The stepped temperature-controlled production system based on a single-stand thick plate rolling line includes a controller and a rolling mill production line. The rolling mill production line is electrically connected to the controller, and the controller is used to control the rolling mill production line to produce according to the stepped temperature-controlled production method based on a single-stand thick plate rolling line.

[0032] The beneficial effects of the step-waiting temperature production method and system based on a single-stand wide and thick plate rolling line according to embodiments of the present invention include, for example:

[0033] Based on the stepped temperature-controlled production method of a single-stand wide and thick plate rolling line, the temperature-controlled time of the intermediate billet of the first slab is obtained; according to the temperature-controlled time of the intermediate billet of the first slab, a preset number of slabs are batch rolled; according to the temperature-controlled time of the intermediate billet of the first slab, the temperature-controlled thickness of the batch rolled slabs is controlled.

[0034] By controlling the waiting time of the intermediate billet of the first slab, the number of slabs to be rolled in batches is selected. Then, based on the waiting time of the intermediate billet of the first slab, the waiting thickness of the batch rolling is controlled, thereby reducing the idle waiting time of the rolling mill and improving the rolling efficiency and rhythm.

[0035] The system is based on a single-stand thick plate rolling mill stepped temperature-controlled production system, including a controller for performing the above-described method. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the steps of a stepped temperature-controlled production method for a single-stand wide and thick plate rolling mill, as provided in an embodiment of the present invention.

[0038] Figure 2 This is a flowchart illustrating the steps of two-piece batch rolling in a stepped temperature-controlled production method for wide and thick plates based on a single-stand rolling mill, as provided in an embodiment of the present invention.

[0039] Figure 3 This is a flowchart illustrating the steps of batch rolling of three or more plates in a stepped temperature-controlled production method based on a single-stand wide and thick plate rolling line, as provided in an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, 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, and therefore should not be construed as a limitation of this invention.

[0044] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0045] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0046] The following is combined Figures 1 to 3 The step-waiting temperature production method based on a single-stand wide and thick plate rolling line provided in this embodiment is described in detail.

[0047] Please refer to Figure 1 The embodiments of the present invention provide a stepped temperature-controlled production method based on a single-stand wide and thick plate rolling line:

[0048] Step S1, obtain t, t is the waiting time of the first slab between the intermediate slab waiting thickness and the final rolling temperature (hereinafter referred to as: the intermediate slab waiting time of the first slab).

[0049] Step S2: Based on the waiting time of the intermediate billet of the first slab, batch rolling is performed on a preset number of slabs.

[0050] Step S3: Control the thickness of the batch-rolled slabs for heating based on the heating time of the intermediate slab of the first slab.

[0051] During batch rolling, there is an idle waiting time between steel plates within the same batch and between rolling intervals. In single-stand rolling, controlled-roll steel plates in the same batch often use the same preheating thickness, selected to ensure the final rolling temperature of the first plate. To reduce the impact of tapping time, the first or first two plates are usually tapped earlier and wait on the roller table. During rolling, the starting rolling temperature of the first or first two plates is lower than that of the second or subsequent plates. Therefore, the waiting time for the second or subsequent plates is relatively longer. Combined with the effects of the number of passes and length, this accumulates into the mill's idle waiting time.

[0052] When two slabs are rolled in a cross-batch manner, after the first slab is rolled and sent away, the intermediate slab temperature of the second slab has not yet cooled to the second-stage rolling temperature, and the mill needs to idle while waiting. The thicker the slab, the greater the reduction required to roll to the desired thickness, the more rolling passes are needed, and the longer the rolling time.

[0053] When rolling 3 to N slabs of the same or similar specifications in batches, the first two slabs can be tapped earlier, with relatively lower initial rolling temperatures, similar thicknesses, and similar waiting times, which can meet rolling requirements. Furthermore, the second slab has little or no waiting time before starting rolling. For the 3rd to Nth slabs, due to the tapping sequence, the initial rolling waiting time decreases with each slab, the initial rolling temperature gradually increases, and the waiting time gradually lengthens. Starting with the third slab, the rolling mill will experience idling waiting time, which increases with each slab, significantly affecting the rolling rhythm.

[0054] By controlling the waiting time of the intermediate billet of the first slab, the number of slabs to be rolled in batches is selected. Then, based on the waiting time of the intermediate billet of the first slab, the waiting thickness of the batch rolling is controlled, thereby reducing the idle waiting time of the rolling mill and improving the efficiency and rhythm of batch rolling.

[0055] In this embodiment, the calculation formula for step S1, which involves obtaining the heating time of the intermediate billet of the first slab, includes: Wherein, the steel plate density ρ = 7800 kg / m³, the steel plate thickness e, the average isobaric specific heat capacity Cp during the isobaric process, the slab initial rolling temperature T1, the second-stage intermediate slab initial rolling temperature T2, and the heat flux density q on the surface of the rolled piece.

[0056] The formula shows that the waiting time is directly proportional to the initial rolling temperature of the slab and the thickness of the intermediate slab, and inversely proportional to the initial rolling temperature of the intermediate slab in the second stage.

[0057] In this embodiment, the first slab is rolled to the intermediate slab thickness. t and the waiting time of the first slab when the nth slab is produced, as mentioned later. t1 is calculated in this way.

[0058] In this embodiment, step S2, based on the intermediate billet waiting time of the first slab, involves batch rolling a preset number of slabs, including:

[0059] Step S21, within 180s≦ When t≦260s, the preset number of blocks for batch rolling is N=2;

[0060] exist When t ≥ 300s, the preset number of blocks N for batch rolling is ≥ 3;

[0061] in, t is the waiting time between the first slab reaching the intermediate slab thickness and the final rolling temperature, s is the time unit in seconds, and N is the preset number of slabs to be rolled in batches.

[0062] Two-slab cross-rolling involves rolling two slabs alternately within the rolling mill. The first slab is rolled to the set intermediate thickness and then exits the mill, waiting at the exit position. After the first slab leaves, the second slab enters and is rolled to the same intermediate thickness, then exits and waits at the mill inlet. After the second slab leaves, the first slab re-enters the mill for finishing rolling, reaching the target thickness while ensuring the final rolling temperature is maintained. Once the first slab has finished rolling and leaves the mill, the second slab re-enters for finishing rolling, reaching the target thickness while maintaining the final rolling temperature. This completes the two-slab cross-rolling process for this batch.

[0063] Two slabs are rolled in a cross-batch process. The first slab is kept at a specific temperature between the intermediate slab thickness and the final rolling temperature required to ensure the process is executed. The time required for the second slab to reach the intermediate slab's temperature is crucial, as the second slab needs to be rolled to the intermediate slab's temperature-controlled thickness while the first slab is waiting. The second slab also needs to complete the finishing rolling stage of the first steel plate during its temperature-controlled period. The temperature-controlled time for the second slab is often longer than the finishing rolling time of the first slab, resulting in a waiting period before the second slab begins rolling. For cross-formed steel plates, the intermediate slab is generally thinner, requiring a larger reduction in the roughing stage, thus necessitating more rolling passes. The thicker the slab, the more roughing passes are required to reach the temperature-controlled point, and the longer the rolling time is also required.

[0064] For example, when rolling a slab from 250mm to a thickness of 60mm before heating, and rolling a slab from 300mm to a thickness of 60mm before heating, the 300mm slab is thicker than the 250mm slab. In the rough rolling stage, it needs to be rolled down by 50mm, which requires at least two more rolling passes. Each pass takes 8-15 seconds. Therefore, the larger the slab, the more rolling time is required in the rough rolling stage.

[0065] In batch rolling of 3 or more N slabs, after the slab is rolled to the set intermediate slab thickness, it leaves the rolling mill and waits at the mill exit until the set batch number N slabs are completed. After the Nth slab leaves the rolling mill and waits at the mill exit, all the waiting steel plates are pulled together from the exit to the mill inlet to wait. Then, according to the process requirements, the finishing rolling stage begins from the first slab.

[0066] The method provided in this embodiment allows all waiting steel plates to be pulled together from the outlet to the rolling mill inlet without any waiting time. The first plate can be directly subjected to finishing rolling. After the first plate is finished and leaves the rolling mill, the second, Nth, and subsequent plates can also begin finishing rolling with little or no waiting time. This batch rolling of N plates is completed in the shortest possible time, improving the rolling cycle.

[0067] The first slab of the same or similar specifications, under the premise of ensuring process execution, the intermediate slab waiting time t. When When t is between 180 and 260 seconds, it can satisfy both the time required for the roughing stage of the second slab and ensure the execution of the finishing rolling process of the first slab, mainly by ensuring that the final rolling temperature is within the process requirements range. If If three slabs are batch rolled between 180 and 260 seconds, and the waiting time for the first slab is insufficient to meet the time required for the rough rolling of the third slab, as well as the time required for transporting the slabs from the mill exit to the mill inlet, the rolling process of the first slab or all slabs will exceed the range, resulting in substandard performance or even scrap steel. If t < 180 seconds, when the first slab is finished rolling and waiting to be heated, the time required for the rough rolling of the second slab cannot be fully met. At this time, the rough rolling of the second slab will occupy the time of the first slab's finishing rolling stage, resulting in insufficient time for the first slab in the finishing rolling stage, and the rolling process cannot be executed.

[0068] Extensive testing and actual production have determined that when When t is between 180 and 260 seconds, two slabs are selected for cross-rolling in batches. Due to the different specifications of the rolled products, the required... The time may vary and should be adjusted appropriately based on actual production conditions.

[0069] Two-block batching criteria (unit: seconds); 180≦ t≦260, t is the heating time of the first slab of the same or similar specifications, provided that the process is executed.

[0070] when When t ≥ 300 seconds, the first and second slabs will have a lot of idling time when rolling two batches of slabs in a cross-rolling process. In this case, it is necessary to select batch rolling of 3 or more N slabs.

[0071] when When t ≥ 300 seconds, select batch rolling of 3 or more N pieces. Because when When t ≥ 300 seconds, the intermediate billet waiting time of the first slab can meet the time required for at least 3 slabs to complete rough rolling, steel plate transportation, and the transportation of all batches of steel plates from the mill exit to the import.

[0072] In this embodiment, step S2, the step of batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab, further includes:

[0073] Step S24, in 260s< When t < 300s, the preset number of blocks for batch rolling is N = 2, and e2 = (e1 - (5mm ~ 15mm)).

[0074] in, t is the thickness of the first slab before it is rolled to the intermediate slab, e1 is the thickness of the first slab before it is heated, and e2 is the thickness of the second slab before it is heated.

[0075] When 260 < If t < 300 seconds, then if two slabs are selected for cross-rolling in batches, there will be a lot of waiting time before the first and second slabs are finished and rolled. If three slabs are selected for batch rolling, the waiting time is not enough. In order to ensure rolling quality and execute the process, two slabs are generally selected for cross-rolling in batches after optimizing the waiting thickness and reducing the waiting time.

[0076] In this embodiment, step S2, which involves batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab, further includes:

[0077] Reference Figure 3 In step S22, when N≥3, the waiting time of the first slab when the nth slab is produced is used as the starting point. t1 controls the output of steel in batch rolling.

[0078] In this embodiment, step S22, when N≥3, is based on the waiting time of the first slab when the nth slab is produced. t1 controls the output of steel in batch rolling, including:

[0079] Step S221, when N≥3, if If t1 ≥ 280~330S, then steel will be tapped; t1≦280~330S, steel tapping ends;

[0080] Where N is the preset number of blocks to be batch rolled. t1 is the waiting time of the first slab when the nth slab is produced. t1.

[0081] When N≥3, starting from the third piece, the waiting time of the first slab when the current piece is tapped is... t1 should be no less than 280-330 seconds; otherwise, the batch tapping should be terminated. The duration varies depending on the specifications of the slab and the rolled steel plate. The waiting time for the first piece of steel when tapping the Nth piece is at this point is... t1 must satisfy the following timeframes: the tapping time of the Nth steel piece, the time from the heating furnace to the rolling mill, the time required for the roughing stage of the Nth steel piece, and the time required for all batches of steel plates to be transported from the rolling mill exit to the entry point. This can be determined through extensive testing and actual production. When t1 is between 280 and 330 seconds, it can meet the time requirements for tapping, rough rolling, and transportation of the next piece of steel. Tapping criteria: t1 ≥ 280~330 seconds, continue producing steel. t1≦280~330 seconds, steel tapping ends.

[0082] Reference Figure 3 That is, when N≥3, after the first slab is tapped, determine... If t1 ≥ 330 seconds, continue tapping; if t1 ≤ 280 seconds, stop tapping. After the second slab is tapped, continue the process. If t1 ≥ 330 seconds, continue tapping; if t1 ≤ 280 seconds, stop tapping. Continue tapping in this manner until all steel is tapped.

[0083] In this embodiment, step S2, which involves batch rolling a preset number of slabs based on the intermediate billet waiting time of the first slab, further includes:

[0084] Step S23, when N≥3; control te- t0 = 90~120s;

[0085] in, te is the waiting time for the nth roughing stage to be completed. t0 is the waiting time for the (n-1)th block to reach the desired temperature.

[0086] The waiting time when the rough rolling stage of this slab is completed te and the previous slab at this time of waiting temperature The time difference (t0) should be at least 70–120 seconds, because the finishing rolling stage generally requires 60–110 seconds, ensuring the execution of the finishing rolling process for the current slab. After the previous slab is finished rolling, the next slab enters the mill for finishing rolling at the fastest possible pace, with no or minimal waiting time. te- t0 = 90~120 seconds, adjusted in real time according to actual production conditions such as billet size, rolling size, initial rolling temperature, and final rolling temperature. Due to the limitation of the thickness waiting to be heated in the process, the rolling gap cannot be completely eliminated or reduced to the maximum extent in multi-batch rolling. After adjustment by this method, the rolling gap time is significantly reduced and the rolling rhythm is significantly improved.

[0087] To ensure the final rolling temperature is accurate and to allow sufficient rolling time for the first piece, an appropriate intermediate billet thickness should be selected within the process range during rolling.

[0088] Reference Figure 2 In this embodiment, step S3, controlling the waiting-to-warm-up thickness of the batch-rolled slabs based on the waiting-to-warm-up time of the intermediate slab of the first slab, includes:

[0089] Step S31, within 180s≦ When t≦260s, e2=(e1-(5mm~15mm);

[0090] Where e1 is the thickness of the first slab to be heated, and e2 is the thickness of the second slab to be heated.

[0091] The intermediate heating time corresponding to the initial heating thickness e1 of the first slab is set based on the slab size, rolling dimensions, initial rolling temperature, and final rolling temperature. t1, adjust the waiting thickness e1 to achieve the intermediate waiting time t1 is between 180 and 260 seconds. The larger the slab size, the longer the rolling length for the same rolling specifications, and the more rolling passes are required in the roughing stage. This is especially affected by the slab thickness; the thicker the slab, the greater the reduction to be achieved in the roughing stage, resulting in more rolling passes and a longer rolling time. Therefore, an intermediate warming time should be set. t1 needs to be longer.

[0092] The finishing rolling stage requires less reduction, fewer rolling passes, and less rolling time. Typically, when rolling slabs of the same specification, the intermediate slabs in the cross-rolling batches are kept to the same thickness during temperature control to ensure rolling stability. After the first slab is finished rolled, the second slab's temperature control time is not yet ready for rolling; the mill needs to idle for about 20-60 seconds. The thicker the slab, the longer the time required for rough rolling, and the longer the waiting time for the second slab after the first slab's rough rolling. To ensure the final rolling temperature of the first slab, the intermediate slab's temperature control time is set longer, resulting in a longer waiting time for rolling the second slab. To reduce or eliminate this waiting time, the intermediate slab's temperature control thickness (e) for the second slab is reduced by 5-15 mm within the process requirements, and the temperature control time is reduced by 20-60 seconds. This eliminates or reduces the pre-rolling waiting time for the second slab, tightens the rolling gap within the cross-rolling batches, and improves the overall rolling rhythm.

[0093] Because the intermediate slab thickness during the cross-rolling of two slabs is generally 50-70mm, each 5mm reduction in thickness, calculated according to the rolling model, reduces the waiting time by 15-20 seconds, varying depending on the thickness. For ease of calculation, the second slab is typically reduced by 5-15mm. In actual production, adjustments are made as needed to achieve optimal results. The goal is that the second slab enters the mill for finishing rolling immediately after the first slab finishes and leaves the mill, with no waiting time.

[0094] The number of passes in the cross-rolling finishing stage is relatively fixed, generally 6 to 7 rolling passes. The reduction rate of the last pass is controlled at 8% to 12%, and the time required is 120 to 160 seconds. In some cases, the second slab has more spare time after the first slab is rolled.

[0095] The thickness of the first slab to be heated is e1, and the thickness of the second slab to be heated is e2 = (e1 - (5~15)). The thickness is adjusted in real time according to the actual production conditions such as slab size, rolling size, initial rolling temperature, and final rolling temperature.

[0096] In this embodiment, step S3, the step of controlling the waiting-to-heat thickness of the batch-rolled slabs based on the waiting-to-heat time of the intermediate slab of the first slab, further includes:

[0097] Step S32, in When t ≥ 300s, E2 = E1; E3 = E1 - 5mm; En = E(n-1) - (0 ~ 10mm);

[0098] En is the thickness to be heated for the nth slab, and E(n-1) is the thickness to be heated for the (n-1)th slab.

[0099] When rolling three or more slabs in batches, the first two slabs can be tapped a certain amount of time in advance, resulting in similar initial rolling temperatures and similar waiting times for the same thickness. During finish rolling, there is little or no waiting time between the second and first slabs. Starting with the third slab, the time for tapping decreases, the initial rolling temperature increases progressively, and the waiting time for the same thickness increases. Finish rolling will then involve mill idling. To eliminate this idling waiting time, the thickness to be heated should be reduced by 5–20 mm per slab within the process range to reduce the waiting time and eliminate the idling waiting time caused by temperature differences and rolling pass variations.

[0100] When rolling three or more slabs in batches, the intermediate slab thickness for heating is generally between 75 and 140 mm. For every 5 mm reduction, the heating time is reduced by 20 to 40 seconds according to the rolling model calculation, depending on the thickness of the slab.

[0101] Similar to cross-rolling, the larger the slab size, especially the slab thickness, the greater the reduction required in roughing, resulting in more rolling passes, longer rolling time, and consequently, longer waiting times or fewer batches. Wider rolling widths lead to greater rolling forces and torques, increasing the number of rolling passes and thus the roughing stage rolling time. Due to various factors, the roughing stage rolling time is typically 120–180 seconds. The finishing stage has a relatively stable number of rolling passes, generally 4–6, requiring 60–110 seconds. Because of the larger gap between steel plates in the roughing stage, and fewer passes and less time in the finishing stage, there is idling time on the mill. To reduce or eliminate this waiting time, the waiting thickness is appropriately optimized.

[0102] Optimization settings for thickness under temperature:

[0103] First block: E1 (Set the required waiting time according to process requirements, planned batch size, etc.).

[0104] The second piece: E2 = E1 (steel roughing out earlier, with similar or lower rolling temperatures during the rolling stage);

[0105] The third part: E3 = E1-5mm (the initial rolling temperature in the roughing stage is slightly higher, and the rolling time difference between the roughing and finishing stages).

[0106] Nth block: En = E(n-1) - (0~10mm) (The initial rolling temperature in the roughing stage is slightly higher, and the rolling time difference between the roughing and finishing stages).

[0107] Note: E1, E2, E3, En, E(n-1) are the corresponding steel plate thicknesses to be heated, and n(n-1) is the thickness of the previous steel plate before the nth plate.

[0108] Long-term production operation research has revealed that optimizing the waiting thickness of most steel plates for temperature rolling within the process range according to different timing sequences can reduce or eliminate mill idling time, thereby improving rolling rhythm and increasing output. The new production method has shown a significant improvement in rolling rhythm in practice.

[0109] Long-term production operation research has revealed that optimizing the waiting thickness of most steel plates for temperature rolling within the process range according to different timing sequences can reduce or eliminate the idling waiting time of the rolling mill, thereby improving the rolling rhythm and increasing output. This also reduces or eliminates the idling waiting time of the rolling mill between steel plates within the same batch during batch rolling.

[0110] Comparative Example 1 and Example 1, which show two slabs being rolled in batches.

[0111] Two slabs are cross-rolled. Taking low alloy Q355B as an example, a slab of 300mm×2200mm×3580mm is rolled into a slab of 30mm×2270mm×34286mm.

[0112] Comparative Example 1: Rolling data is shown in Table 1.

[0113] Table 1 Comparative rolling data

[0114]

[0115] Example 1: Rolling data is shown in Table 2.

[0116] Table 2 Rolling data of the example

[0117]

[0118] The original plan had an average waiting time of 63.6 seconds for the second piece, while the new plan had an average waiting time of 8.5 seconds. After implementing the new plan, the average waiting time for each crossover group was reduced by 55.1 seconds. The number of 300mm slabs processed per hour increased from approximately 10.0 pieces / hour to approximately 11 pieces / hour. This represents an efficiency improvement of approximately 1 / 10 = 10%.

[0119] Comparative Example 2 and Example 2, which describe batch rolling of three or more slabs.

[0120] For batch rolling of three or more pieces, taking low alloy Q355B as an example, a slab of 250mm×2000mm×3100mm is rolled into 50mm×2470mm×12375mm pieces, and then rolled in batches of 5 pieces.

[0121] Comparative Example 2: Rolling data for 5 blocks in batch 5 are shown in Table 3.

[0122] Table 3

[0123]

[0124] Example 2: Rolling data for 5 blocks in a batch is shown in Table 4.

[0125] Table 4

[0126]

[0127] After implementing the example, the number of steel plates produced per hour for 250mm slabs increased from approximately 12.1 plates / hour to approximately 13.0 plates / hour. This represents an efficiency increase of approximately 0.9 / 12.1 = 7.5%.

[0128] The method provided in this embodiment, after being implemented on a 4300mm wide and thick plate rolling line, significantly improved the rolling rhythm when rolling 16-60mm temperature-controlled steel plates that meet the requirements. The number of plates per hour on similar steel plate mills increased from an average of about 12 to about 13, representing an improvement in rhythm efficiency of approximately 8%. The production method provided in this embodiment has shown a significant improvement in rolling pace in practice.

[0129] The step-waiting temperature production method based on a single-stand wide and thick plate rolling mill provided in this embodiment has at least the following advantages:

[0130] By controlling the waiting time of the intermediate billet of the first slab, the number of slabs to be rolled in batches is selected. Then, based on the waiting time of the intermediate billet of the first slab, the waiting thickness of the batch rolling is controlled, thereby reducing the idle waiting time of the rolling mill and improving the rolling efficiency and rhythm.

[0131] By optimizing the thickness of intermediate billets rolled alternately at different times during the rolling of performance steel plates on a single-stand wide and thick plate mill, the idling waiting time of the mill can be reduced or eliminated, the rolling rhythm can be improved, unnecessary waiting time can be reduced, time can be saved, the effective operating rate of the mill can be increased, and the output can be increased.

[0132] Embodiments of the present invention also provide a stepped temperature-controlled production system based on a single-stand thick plate rolling line. The system includes a controller and a rolling mill production line. The rolling mill production line is electrically connected to the controller, which controls the rolling mill production line to produce according to the stepped temperature-controlled production method based on a single-stand thick plate rolling line.

[0133] Production planning and scheduling are strictly implemented according to regulations, grouping steel plates of the same specification and type together as much as possible. Rolling thickness changes are smooth and gradual. The heating temperature of the slab in the heating furnace is uniform, with a cross-sectional temperature difference of less than or equal to 25℃, and the exit temperature strictly adheres to the process specifications. The rolling process is coordinated and adjusted to maximize the range of thickness adjustments while maintaining performance, thus meeting more flexible rolling requirements. Production operators plan the rolling production method in advance, initially planning single-rolling, cross-rolling, and batch rolling methods based on the production plan, billet size, rolling dimensions, steel grade, and process. During production, new technical solutions are used to adjust the rolling process in real time according to actual conditions. New technical solutions are flexibly applied to maximize the rolling pace while ensuring quality.

[0134] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A stepped temperature-controlled production method based on a single-stand wide and thick plate rolling line, characterized in that: Get t, t is the waiting time for the first slab to be heated from the intermediate slab thickness to the final rolling temperature; According to the above t, batch rolling of a preset number of slabs; According to the above t, the thickness of the slab waiting to be heated in batch rolling is controlled, and it is kept below 180s. When t≦260s, e2=(e1-(5mm~15mm)), and the preset number of blocks for batch rolling N=2, where e1 is the thickness of the first slab to be heated and e2 is the thickness of the second slab to be heated.

2. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 1, characterized in that, According to the The steps for batch rolling of a predetermined number of slabs include: exist When t ≥ 300s, the preset number of blocks N for batch rolling is ≥ 3; Where s is the time unit in seconds, and N is the preset number of blocks to be rolled in batches.

3. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 2, characterized in that, According to the The step of batch rolling a predetermined number of slabs also includes: When N≥3, the waiting time of the first slab when the nth slab is produced is used as the reference. t1 controls the output of steel in batch rolling.

4. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 3, characterized in that, When N≥3, the waiting time of the first slab when the nth slab is produced is used as the reference. t1, the steps for controlling the tapping of steel in batch rolling include: When N≥3, if If t1 ≥ 330S, then steel will be tapped; t1≦280S, steel tapping ends; Where N is the preset number of blocks to be batch rolled. t1 is the waiting time of the first slab when the nth slab is produced. t1.

5. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 3, characterized in that, According to the The step of batch rolling a predetermined number of slabs also includes: When N≥3; control te- t0 = 90~120s; in, te is the waiting time for the nth roughing stage to be completed. t0 is the waiting time for the (n-1)th block to reach the desired temperature.

6. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 1, characterized in that, According to the The steps for controlling the thickness of slabs to be rolled at temperature in batches include: exist When t ≥ 300s, E2 = E1; E3 = E1 - 5mm; En = E(n-1) - (0 ~ 10mm); En is the thickness to be heated for the nth slab, and E(n-1) is the thickness to be heated for the (n-1)th slab.

7. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to any one of claims 1-6, characterized in that, The acquisition The formula for calculating step t includes: Wherein, the steel plate density ρ=7800kg / m³, the steel plate thickness e, the average isobaric specific heat capacity Cp during the isobaric process, the slab initial rolling temperature T1, the second-stage intermediate slab initial rolling temperature T2, and the heat flux density q on the surface of the rolled piece.

8. The method for stepped temperature-controlled production on a single-stand wide and thick plate rolling line according to claim 1, characterized in that, According to the The step of batch rolling a predetermined number of slabs also includes: In 260s When t < 300s, the preset number of blocks for batch rolling is N = 2, and e2 = (e1 - (5mm ~ 15mm)).

9. A stepped temperature-controlled production system based on a single-stand wide and thick plate rolling line, characterized in that, The single-stand thick plate rolling line stepped temperature-controlled production system includes a controller and a rolling mill production line. The rolling mill production line is electrically connected to the controller. The controller is used to control the rolling mill production line to carry out production according to the single-stand thick plate rolling line stepped temperature-controlled production method according to any one of claims 1-8.

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