Method for automatic control of the production rhythm of a hot rolling line

Abstract

The application discloses a kind of hot rolling line production rhythm automatic control method, belong to steel rolling automation control technical field.The method of the present application calculates the rolling rhythm of each slab at furnace head, i.e., slab to be rolled out of furnace, can calculate the actual rolling rhythm according to specification, variety, rolling line process change;At the same time, according to the variety of slab in furnace, charging state, the tapping rhythm of slab in furnace is also calculated in real time when charging and tapping, to realize the coordination of rolling line rolling rhythm and heating furnace tapping rhythm;The present application not only solves the coordination problem of rolling line rolling rhythm and heating furnace tapping rhythm, but also realizes the controllable heating quality, rolling line rhythm balance, and further realizes the efficient automatic tapping of the whole production line.

Description

Technical Field

[0001] This invention belongs to the field of steel rolling automation control technology, and more specifically, relates to a method for automatic control of the production rhythm of a hot rolling line. Background Technology

[0002] To further improve production efficiency, domestic hot rolling lines are striving to increase their automation levels. The production rhythm of domestic hot rolling lines is either controlled by the heating furnace or by the rolling line itself. The furnace-controlled method, with the furnace as the center, triggers tapping as long as the heating quality meets the requirements of the heating schedule. However, it doesn't fundamentally address the bottlenecks in different areas of the rolling line after the slab exits the furnace, or the impact of changes in slab length, width, and rolling temperature on the rolling line rhythm, leading to slab swaying. The rolling line-controlled method, with the rolling line as the center, will tap steel as long as the rolling line has the capacity. This results in situations where, for wide-gauge slabs, the rolling line's capacity exceeds the furnace's, leading to underheated slabs and insufficient heating quality. Conversely, for narrow-gauge slabs, the heating capacity exceeds the rolling line's, causing the slabs to wait at the furnace head. This inherent contradiction hinders the simultaneous improvement of hot rolling line production efficiency and heating quality.

[0003] A search revealed that application number 2018106785600 discloses a fully automatic hot rolling steel extraction method, which introduces a method for controlling the steel extraction rhythm using historical data values ​​in a relational table, but does not consider changes in production rhythm caused by changes in heating quality and rolling process.

[0004] Application No. 202010775507X provides a control system for the tapping rhythm of a hot rolling furnace. It discloses a method for calculating the heating and tapping rhythm based on the minimum furnace time, using the fastest tapping rhythm in the rolling line theory as a benchmark. Although this method links the heating quality with the tapping rhythm, the rolling line rhythm is treated as a fixed value. It does not solve the bottleneck problem in each area of ​​the rolling line, nor does it consider the impact of thickness changes, slab length changes, process changes, etc. on the rolling line rhythm. This can lead to steel sloshing in the rolling line and large temperature loss in the line. Summary of the Invention

[0005] 1. The problem to be solved

[0006] This invention aims to provide a method for automatic control of the production rhythm of a hot rolling line. It calculates both the steel tapping bottleneck of the heating furnace on the hot rolling line and the rhythm bottleneck of the rolling process in each area of ​​the rolling line, thereby coordinating and controlling the steel tapping rhythm of the heating furnace and the rolling rhythm of the rolling line, realizing integrated and high-quality automatic control of the production rhythm of the hot rolling line.

[0007] 2. Technical Solution

[0008] To solve the above problems, the present invention adopts the following technical solution.

[0009] The present invention provides a method for automatic control of the production rhythm of a hot rolling line, comprising the following processes:

[0010] S1. Calculate the tapping rhythm FPC of the heating furnace;

[0011] When each slab is loaded into the furnace, the target heating time T is found from the target heating time lookup table. At the same time, based on the current number of slabs N in the furnace, the tapping rhythm FPC when this slab is loaded into the furnace is calculated, FPC = T / N, and then entered into the database table.

[0012] For slabs already in the furnace, the timer starts from the actual time they enter the furnace. Each time a tapping or charging signal is received, the actual heating time Tj for each slab in the furnace is refreshed, where Tj = current time - slab entry time. At the same time, the remaining heating time Ts for each slab in the furnace is also refreshed, where Tsj = target heating time - actual heating time, and Tsj refers to the remaining heating time of the j-th slab in the furnace. When the remaining heating time Ts is less than 0, Ts is set to 0. The tapping rhythm FPC for each slab in the furnace is updated synchronously, where FPCj = remaining time Tsj / current slab sequence number in the furnace. The longest tapping rhythm time for the slab in the furnace is calculated, i.e., FPC = max(FPC1, FPC2, FPC3, ...), and this is used as the tapping rhythm FPC of the heating furnace.

[0013] S2, Calculate the steel output rhythm MPC of the rolling mill;

[0014] The rolling line is divided into reasonable zones according to the rolling interlocking conditions. The pure rolling time, handling time and allowance time are calculated for each zone. The MPC time for each zone is equal to the pure rolling time plus the handling time plus the allowance time.

[0015] The pure rolling time for each zone is calculated according to the rolling schedule; the transport time for each zone is calculated according to the length and transport speed of each zone on the rolling line; the margin time is maintained in the rhythm table, and the margin time is differentiated according to the steel grade, and is generally defaulted to 20 seconds.

[0016] The longest MPC time in each rolling mill zone is calculated as the mill's tapping rhythm MPC. Specifically, this is combined with... Figure 2 As shown, the main equipment in the rolling mill includes the roughing mill descaling mill (HSB), the pressure width-fixing mill (SSP), the No. 1 roughing mill (R1), the No. 2 roughing mill (R2), the head cutter (CS), the finishing mill (FM), and the coiler (DC). The areas between these pieces of equipment are sequentially divided into the HSB area, SSP area, R1 area, R2 area, CS area, FM area, and DC area. The steel output rhythm of the rolling mill is MPC = max(T). HSB T SSP T R1T R2 T CS T FM T DC ), where T HSB T SSP T R1 T R2 T CS T FM T DC Refers to the MPC time of each corresponding region.

[0017] S3. Calculate the production line rhythm PC. When the slab reaches the furnace head, the furnace head signal will be triggered. The steel tapping system compares the values ​​of MPC and FPC. The larger value is taken as the production line rhythm, i.e., PC = max(MPC, FPC).

[0018] S4. Calculate the timing of steel tapping;

[0019] To eliminate the influence of the distance between heating furnaces on the tapping rhythm, the inherent time of the slabs from each heating furnace before reaching the HSB for hot inspection was first measured and denoted as T. F1 T F2 T F3 ···T Fn n refers to the number of heating furnaces;

[0020] When the first slab arrives at the furnace head, the tapping system checks whether the rolling mill and heating furnace equipment are in automatic mode. If any equipment is not in automatic mode, automatic tapping is prohibited. If all equipment in the rolling mill and heating furnace is in automatic mode, automatic tapping is initiated according to the calculated production rhythm PC, and a countdown PC begins. s ;

[0021] When a second slab or multiple slabs arrive at the furnace head, the tapping calculation is performed according to the order in which the slabs arrive. First, the furnace number of the heating furnace where the slab is located is determined, and the corresponding T is found. F1 The value is then compared with the PC value. s With T Fn The size of the PC s ≤T Fn Then, a steel tapping signal can be issued for this piece of steel, and the production line rhythm PC for this piece of steel can be calculated according to the above rules, and the countdown PC can be restarted again. s This cycle repeats continuously, achieving production line rhythm control.

[0022] Taking a production practice with three sets of heating furnaces as an example, the above process is as follows: First, measure the inherent time of the slabs from each heating furnace before they reach the HSB for hot inspection, and record it as T. F1 T F2 T F3When the first slab arrives at the furnace head, the tapping system checks whether the rolling mill and heating furnace equipment are in automatic mode. If any equipment is not in automatic mode, automatic tapping is prohibited. If all equipment in the rolling mill and heating furnace is in automatic mode, automatic tapping is initiated according to the calculated rhythm PC, and a countdown PC begins. s When a second slab or multiple slabs arrive at the furnace head, the tapping calculation is performed according to the order in which the slabs arrive at the furnace head. First, the furnace number of the heating furnace where the slab is located is determined, and the corresponding T is found. F1 \T F2 \T F3 The value is then compared with the PC value. s With T F1 \T F2 \T F3 The size of the PC s ≤(T F1 \T F2 \T F3 Then, a steel tapping signal can be issued for this piece of steel, and the production line rhythm PC for this piece of steel can be calculated according to the above rules, and the countdown PC can be restarted again. s This cycle repeats continuously, achieving production line rhythm control.

[0023] 3. Beneficial effects

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The present invention provides an automatic control method for the production rhythm of a hot rolling line, which uses the heating time of the heating furnace as a guarantee of heating quality and is also strongly correlated with the steel tapping rhythm of the heating furnace; the area of ​​the rolling line is divided into bottlenecks, and the bottleneck time of each slab in the rolling line is identified as the rolling rhythm of the rolling line, thereby improving the operating efficiency of the rolling line.

[0026] (2) This invention combines the steel tapping rhythm of the heating furnace and the rolling rhythm of the rolling line, and uses the bottleneck as the production line rhythm to achieve balanced and efficient operation of the heating furnace and the rolling line, and also realizes automatic control of the hot rolling production line rhythm.

[0027] (3) The production rhythm control of the hot rolling line is the basis for the efficient operation of the hot rolling mill. The method of this invention calculates the rolling rhythm of each slab at the furnace head that is about to be rolled out of the furnace. The actual rolling rhythm can be calculated according to the changes in specifications, varieties and rolling line processes. At the same time, during loading and unloading, the unloading rhythm of the slab in the furnace is also calculated in real time according to the variety of slab in the furnace and the loading status, so as to achieve the coordination between the rolling rhythm of the rolling line and the unloading rhythm of the heating furnace. This invention not only solves the problem of coordinating the rolling rhythm of the rolling line and the unloading rhythm of the heating furnace, but also achieves qualified heating quality and balanced rolling rhythm, and realizes efficient automatic unloading of the entire production line. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0029] Figure 2 This is a schematic diagram of the rolling mill area layout in this invention. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments.

[0031] Example

[0032] Combination Figure 1 and Figure 2 The method for automatic control of the production rhythm of the hot rolling line in this embodiment is implemented as follows:

[0033] Determine the target heating time for the slab based on the heating process requirements.

[0034] The minimum time a slab spends in the furnace is subject to specific targets. Different steel grades have different target heating times, and the time spent in the furnace also differs between cold-charged and hot-charged slabs. Therefore, the target heating time can be queried using a data table. When each slab enters the furnace, a query signal is triggered to find the corresponding target heating time T, as shown in Table 1 below.

[0035] Table 1 Target Heating Time Lookup Table

[0036] steel grades Time spent in the furnace for cold-charged billets (min) Hot-charged billet time in the furnace (min) steel1 180 150 steel2 190 160 steel3 200 170 steel4 205 175 Steel5 210 180

[0037] S1. Calculate the tapping rhythm FPC of the heating furnace;

[0038] When each slab is loaded into the furnace, the target heating time T is retrieved from the target heating time table (see Table 1 above). Simultaneously, based on the current number of slabs N in the furnace, the tapping rhythm FPC for that slab is calculated: FPC = T / N, and entered into the database table. For slabs already in the furnace, timing begins from the actual loading time. Each time a tapping or loading signal is received, the actual heating time Tj for each slab in the furnace is updated: Tj = current time - slab loading time. The remaining heating time Ts for each slab in the furnace is also updated: Tsj = target heating time - actual heating time. If the remaining heating time Ts is less than 0, Ts is set to 0. The tapping rhythm FPC for each slab in the furnace is then updated: FPCj = remaining time Tsj / current slab's furnace sequence number. The longest tapping rhythm time for a slab in the furnace is calculated, i.e., FPC = max(FPC1, FPC2, FPC3, ...), and this is used as the tapping rhythm of the heating furnace. See Table 2 below for details.

[0039] Table 2. Calculation Table for Steel Tapping Rhythm of Slab

[0040]

[0041] S2, Calculate the steel output rhythm MPC of the rolling mill;

[0042] The rolling line is rationally divided into zones according to the rolling interlocking conditions. The pure rolling time, handling time, and allowance time are calculated for each zone. The MPC time for each zone = pure rolling time + handling time + allowance time, such as... Figure 2 As shown in the diagram, the rolling mill is divided into zones according to the layout diagram of the rolling mill equipment. The zones, transport distances, transport speeds, and acceleration / deceleration are detailed in Table 3 below. The time definitions for each zone of the rolling mill are shown in Table 4 below.

[0043] The pure rolling time for each zone is calculated according to the rolling schedule; the transport time for each zone is calculated based on the length and transport speed of each zone on the rolling line; the allowance time is maintained in the rhythm table, and the allowance time is differentiated according to the steel grade, generally defaulting to 20 seconds.

[0044] To better illustrate and describe the calculation process of the rolling mill's output rhythm MPC, the calculation process is described with a thickness, width, and length of 230mm, 1610mm, and 9500mm respectively, an intermediate billet thickness of 44mm, and a finished product thickness and width of 3mm and 1520mm respectively.

[0045] Table 3. Rolling Line Zone Division Table

[0046] HSB SSP R1 R2 CS FM DC Definition of region length variable <![CDATA[L HSB ]]> <![CDATA[L SSP ]]> <![CDATA[L R1 ]]> <![CDATA[L R2 ]]> <![CDATA[L CS ]]> <![CDATA[L FM ]]> <![CDATA[L DC ]]> Distance (m) 20 35 90 120 15 33 150 Regional transport speed variable definition <![CDATA[V HSB ]]> <![CDATA[V SSP ]]> <![CDATA[V R1 ]]> <![CDATA[V R2 ]]> <![CDATA[V CS ]]> <![CDATA[V FM ]]> <![CDATA[V DC ]]> Transport speed (m / s) 1.2 1.5 3.5 4 0.8 / / Regional acceleration variable definition <![CDATA[a HSB ]]> <![CDATA[a SSP ]]> <![CDATA[a R1 ]]> <![CDATA[a R2 ]]> <![CDATA[a CS ]]> <![CDATA[a FM ]]> <![CDATA[a DC ]]> Acceleration / deceleration (m / s²) 0.5 0.5 1 1 0.5 0.25 / -0.5 1

[0047] Table 4 Definition of Time Names for Rolling Zones

[0048]

[0049] Important parameters such as side pressure step length, roughing rolling data, and finishing rolling data are obtained from the rolling schedule calculated by the rolling model.

[0050] The side pressure steps of each slab passing through the SSP are obtained from the rolling model; the number of roughing mill passes and the length of the intermediate slab in each pass, and the rolling speed; the rolling speed and rolling length of the finishing mill. Specific parameters are shown in Tables 5, 6, and 7.

[0051] Table 5 SSP Side Pressure Step Count Table

[0052]

[0053]

[0054] This is the SSP procedure for side-pressing a 230*1610*9500mm slab to a width of 1530mm, which requires a total of 29 steps. This side-pressing step count table is obtained from the rolling model of the production line. The length and time of each step are fixed at 1.43s.

[0055] Table 6 Rough Rolling Specifications

[0056]

[0057] This was calculated using a 230*1610*9500mm slab, with an intermediate slab thickness of 44mm, and roughing specifications, based on a rolling mold.

[0058] Table 7 Finishing Rolling Specifications

[0059]

[0060]

[0061] This is a finishing rolling process using a 230*1610*9500mm slab, an intermediate slab thickness of 44mm, and a finished product of 3.00*1530mm. The rolling model was used to calculate the threading speed, maximum speed, and the steel ejection speed of F7.

[0062] The speed at which the coiled steel is thrown is fixed at 4.2 m / s; the deceleration is fixed at -0.5 m / s².

[0063] The following details the calculation process for pure rolling time, handling time, and allowance time in each area:

[0064] I. Calculation of pure rolling time in each region:

[0065] 1) The HSB area has no pure rolling time, only handling time.

[0066] 2) SSP Zone: The pure rolling time in this zone is the time from when the slab head contacts the SSP hammer to when the slab tail leaves the SSP hammer, which is the pure hammer impact time, or TZ. SSP = 1.43 * number of steps, for the 230*1610*9500mm slab given above, side-pressed to a width of 1530mm, TZ SSP =1.43*29=41.47s.

[0067] 3) R1 region: Pure rolling time refers to the rolling time of R1 pass and the round-trip time between gaps. The round-trip time is fixed at 7s. Using the acceleration / deceleration in Table 3 and the exit length, bite speed and running speed of each pass in Table 6, the pure rolling time of each pass can be calculated using t=L / V and (v-v0)=a*t. Using the data in Table 6, the calculated pure rolling time is 30.87s, as shown in Table 8.

[0068] Table 8R1 Pure Rolling Time Calculation Table

[0069]

[0070] 4) R2 region: The calculation process for the pure rolling time in the R2 region is the same as that in the R1 region. Using the data in Table 6, the calculated pure rolling time is 37.45s, as shown in Table 9.

[0071] Table 9. Calculation of Pure Rolling Time for R2

[0072]

[0073]

[0074] 5) CS area: This area only has handling time, not pure rolling time.

[0075] 6) FM Zone: Pure rolling time refers to the time from when the strip head reaches F1 to when the strip tail leaves F7. The total length of the strip is constant and can be calculated using the principle of constant volume. The distance between each stand is 5.5m. The time for the strip to travel from F1 to F7 can be calculated using the distance between stands and the speed of the current stand. The head acceleration time is obtained using the basic acceleration formula t = (V - V0) / a, and the tail deceleration time is also obtained using the basic acceleration formula t = (V - V0) / a. The travel distance for both the head acceleration time and the tail deceleration time is calculated using the formula S = (V - V0) / a. 2 -V0 2 The distance obtained is ) / 2a, and the remaining part is the running distance in the middle. Dividing it by the running speed gives the required running time in the middle.

[0076] Based on the principle that the volume of steel remains constant, using a slab with a thickness, width, and length of 230mm, 1610mm, and 9500mm respectively, a 44mm intermediate slab is rolled, resulting in a finished product with a thickness and width of 3mm and 1520mm respectively. The calculated finished product length is 771.46m. The acceleration time at the head end, deceleration time at the tail end, and the running time at the middle end, calculated using the FM acceleration of 0.25m / s² and deceleration of -0.5m / s² given in Table 3, and the data in Table 7, are shown in Table 10.

[0077] Table 10FM Zone Pure Rolling Time Calculation Table

[0078]

[0079] FM pure rolling time = threading time + head acceleration time + tail deceleration time + running time = 78.18s.

[0080] 7) DC area: The pure rolling time in the DC area is consistent with the rolling time of the F7 stand, that is, the head acceleration time + tail deceleration time + middle running time of the finishing rolling area = 65.12s.

[0081] II. Calculation of handling time for each area:

[0082] 1) HSB Zone: The HSB zone is 20 meters long, extending from the HSB inlet thermal detector to the SSP inlet. The handling speed is 1.2 m / s, and the handling time is TB. HSB =L HSB / V HSB =20 / 1.2 = 16.67s.

[0083] 2) SSP Area: The time it takes for the slab to be transported from the SSP outlet to the R1 inlet. This distance is 35m. Due to the presence of the slab, the actual transport distance should be reduced by the slab length. Transport time TB SSP =(L SSP -Bullet length) / V SSP =(35-230*1610*9500 / 230 / 1530 / 1000) / 1.5=16.66s.

[0084] 3) R1 area: The time it takes for the slab to be transported from the R1 exit to the R2 entrance. This distance is 90m. Due to the presence of the slab, the actual transport distance should be reduced by the slab length. The transport time is TB. R1 =(L R1 -Bullet length) / V R1 = (90-17.71) / 3.5 = 20.65s. Note: The billet length at this time can be obtained from Table 6.

[0085] 4) R2 area: The time it takes for the slab to be transported from the R2 exit to the CS entrance. This distance is 120m. Due to the presence of the slab, the actual transport distance should be reduced by the slab length. Transport time TB R2 =(L R2 -Bullet length) / V R2 = (120-54) / 4 = 16.5s. Note: The billet length at this time can be obtained from Table 6.

[0086] 5) CS Area: The time it takes for the slab to be transported from the CS exit to the F1 entrance. This distance is 15m. Due to the presence of the slab, the actual transport distance should be reduced by the slab length. Transport time TB CS =L CS / V CS =15 / 0.8=18.75s.

[0087] 6) There is no moving time in the FM area.

[0088] 7) DC area: The time it takes for the tail of the slab to be transported from the F7 exit to the DC entrance, and this distance is 150m.

[0089] The handling time depends on the throwing speed of F7, the throwing speed of DC, and the deceleration of DC. The throwing speed of F7 is derived from the finishing rolling schedule (Table 6), the throwing speed of DC is a fixed value of 4.2 m / s, and the deceleration of DC is also a fixed value of -0.5 m / s. First, calculate the required deceleration t1 = (V - V0) / a using the formula t = (V - V0) / a. DC ) / a=(11.5-4.2) / 4.2=14.6s, the distance required for deceleration S=(V 2 -V DC 2 ) / 2a=(11.5^2-4.2^2) / (2*0.5)=114.61m, the time t2 of the uniform speed segment=(L DC -S) / V=(150-114.61) / 11.5=3.077s. Transportation time (TB) in the DC area. DC =t1+t2=14.6+3.077=17.677s.

[0090] III. Calculation of Margin Time

[0091] To ensure safe distances in each area, a margin time will be set separately for each area. To simplify calculations, this margin time will be uniformly set to 20 seconds.

[0092] To better illustrate the calculation process and approach for the rolling mill rhythm, the above calculation results are summarized in Table 11, which makes it easy to obtain the MPC time for each region.

[0093] Table 11 Rolling Line Rhythm Calculation Table

[0094]

[0095] The longest time for each steel tapping zone in the rolling mill is determined and used as the rolling rhythm MPC of the rolling mill. In the table above, 102.797 seconds in the DC zone is taken as the rolling rhythm of this coil.

[0096] S3. Production line rhythm PC calculation. When the slab reaches the furnace head, a furnace head signal is triggered. The steel tapping system compares the values ​​of MPC and FPC. The larger value is used as the production line rhythm, i.e., PC = max(MPC, FPC).

[0097] S4. Calculation of tapping timing. To eliminate the influence of the distance between heating furnaces on the tapping rhythm, the inherent time for the hot inspection of the slab before it reaches the HSB from each heating furnace must be determined first. Taking three groups of heating furnaces as an example, these times are denoted as T. F1 T F2 T F3 When the first slab arrives at the furnace head, the tapping system checks whether the rolling mill and heating furnace equipment are in automatic mode. If any equipment is not in automatic mode, automatic tapping is prohibited. If all equipment in the rolling mill and heating furnace is in automatic mode, automatic tapping is initiated according to the calculated rhythm PC, and a countdown PCs begins. When a second slab or multiple slabs arrive at the furnace head, the tapping calculation is performed according to the order in which the slabs arrive at the furnace head. First, the furnace number of the heating furnace containing the slab is determined, and the corresponding (T) is found. F1 \T F2 \T F3 The value of ) is then compared with that of PCs and (T). F1 \T F2 \T F3 The size of ) if PCs ≤ (T) F1 \T F2 \T F3 Then, a steel tapping signal can be issued for this piece of steel. At the same time, the production line rhythm PC for this piece of steel is calculated according to the above rules, and the countdown PCs is restarted again. This cycle repeats to achieve production line rhythm control.

[0098] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A method for automatically controlling the production rhythm of a hot rolling line, characterized in that, Includes the following processes: S1. Calculate the tapping rhythm FPC of the heating furnace; the process is as follows: When each slab is loaded into the furnace, the target heating time T is found from the target heating time lookup table. At the same time, based on the current number of slabs N in the furnace, the tapping rhythm FPC when this slab is loaded into the furnace is calculated, FPC=T / N, and then entered into the database table. For slabs already in the furnace, the timer starts from the actual time of entry into the furnace. Each time a tapping signal or a charging signal is received, the actual heating time Tj of each slab in the furnace must be updated. Tj = current time - slab entry time. At the same time, the remaining heating time Ts of each slab in the furnace must also be updated. Tsj = target heating time - actual heating time. When the remaining heating time Ts is less than 0, Ts is set to 0. The tapping rhythm FPC of each slab in the furnace is updated synchronously. FPCj = remaining time Tsj / current slab sequence number in the furnace. Calculate the longest tapping rhythm time of the slab in the furnace, i.e., FPC=max(FPC1, FPC2, FPC3, ...), and use it as the tapping rhythm FPC of the heating furnace. S2. Calculate the mill's tapping rhythm (MPC); the process is as follows: The rolling line is divided into reasonable zones according to the rolling interlocking conditions. The pure rolling time, handling time and allowance time are calculated for each zone. The MPC time for each zone is equal to the pure rolling time plus the handling time plus the allowance time. The pure rolling time for each zone is calculated according to the rolling schedule; the transport time for each zone is calculated based on the length and transport speed of each zone on the rolling line; and the allowance time is maintained in the rhythm table. Find the longest MPC time in each rolling mill zone as the mill's tapping rhythm MPC; S3. Calculate the production line rhythm PC. When the slab reaches the furnace head, the furnace head signal will be triggered. The steel tapping system compares the values ​​of MPC and FPC. The larger value is taken as the production line rhythm, i.e., PC = max(MPC, FPC). S4. Calculate the timing for tapping steel.

2. The method for automatic control of production rhythm of a hot rolling line according to claim 1, characterized in that: The calculation process for the timing of tapping steel in S4 is as follows: To eliminate the influence of the distance between heating furnaces on the tapping rhythm, the inherent time of the slab before hot inspection before reaching the HSB from each heating furnace was first measured and denoted as T. F1 T F2 T F3 ···T Fn n refers to the number of heating furnaces; When the first slab arrives at the furnace head, the tapping system checks whether the rolling mill and heating furnace equipment are in automatic mode. If any equipment is not in automatic mode, automatic tapping is prohibited. If all equipment in the rolling mill and heating furnace is in automatic mode, automatic tapping is initiated according to the calculated production rhythm PC, and a countdown PC begins. s ; When a second slab or multiple slabs arrive at the furnace head, the tapping calculation is performed according to the order in which the slabs arrive. First, the furnace number of the heating furnace where the slab is located is determined, and the corresponding T is found. Fn The value is then compared with the PC value. s With T Fn The size of the PC s ≤T Fn Then, a steel tapping signal can be issued for this piece of steel, and at the same time, according to the calculated production line rhythm PC for this piece of steel, the countdown PC will be restarted again. s This cycle repeats continuously, achieving production line rhythm control.

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