Plate thickness control device of tandem rolling mill

Abstract

To provide a plate thickness control device of a tandem rolling mill that can suppress the influence of eccentricity of a work roll and achieve high-precision control of the outlet side plate thickness of a final stand even when a plate thickness gauge is not installed on the inlet side of the final stand.SOLUTION: A plate thickness control device includes a mass flow plate thickness calculation unit and a final stand plate thickness control unit. The mass flow plate thickness calculation unit calculates the mass flow plate thickness at the outlet side of a preceding stand using the inlet side plate thickness actual value measured by an inlet side plate thickness gauge installed on the inlet side of the preceding stand arranged immediately before the final stand, the inlet side plate speed actual value measured by an inlet side plate speed meter arranged on the inlet side of the preceding stand, and the outlet side plate speed actual value measured by an outlet side plate speed meter arranged on the outlet side of the preceding stand. The final stand plate thickness control unit performs feedforward AGC for the final stand using the mass flow plate thickness calculated by the mass flow plate thickness calculation unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a plate thickness control device for a tandem rolling mill that controls the plate thickness of a material being rolled by a tandem rolling mill having a plurality of rolling stands. [Background technology]

[0002] In a rolling line (e.g., a cold rolling line) where a tandem rolling mill is installed, thickness control is performed so that the thickness of the material being rolled becomes a target thickness (hereinafter also referred to as "product thickness"). As this type of thickness control, feedforward AGC (Automatic Gauge Control) is known. In feedforward AGC, a thickness gauge installed on the entry side of a rolling stand (hereinafter also simply referred to as a "stand") is used to operate (change) the gap between the upper and lower work rolls (hereinafter referred to as "roll gap") by a reduction control device and to operate (change) the peripheral speed of the work rolls by a speed control device so that the thickness on the exit side of the stand becomes the target thickness.

[0003] By the way, when a thickness gauge is not installed at the entry side of the final stand, the actual thickness value at the entry side of the final stand cannot be obtained, so feedforward AGC is generally not applied to the final stand. In this case, mass flow AGC or monitor AGC is applied to the final stand instead of feedforward AGC.

[0004] When mass flow AGC is applied to the final stand, the strip speed measured by a strip speed meter installed at the exit of the final stand is used. When monitor AGC is applied to the final stand, the strip thickness measured by a strip thickness meter installed at the exit of the final stand is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-57317 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the actual strip speed and thickness values ​​at the final stand delivery are affected by the eccentricity of the work rolls up to the final rolling stand, and using these actual values ​​would result in a decrease in the accuracy of the product strip thickness. It is conceivable to eliminate the effect of the eccentricity of the work rolls by controlling the roll gap so that the roll gap, which changes periodically according to the eccentricity of the work rolls, becomes constant, but this is difficult because the response of a typical electric roll gap controller is slow.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a plate thickness control device for a tandem rolling mill that can suppress the influence of eccentricity of the work rolls and control the plate thickness on the delivery side of the final stand with high accuracy even when a plate thickness gauge is not installed on the entry side of the final stand. [Means for solving the problem]

[0008] A first aspect of the present disclosure relates to a thickness control device for a tandem rolling mill. The thickness control device controls the thickness of a material to be rolled in a tandem rolling mill having a plurality of rolling stands. Each rolling stand has a work roll. The rolling stand arranged at the end of the conveying direction of the material to be rolled is the final stand, and the rolling stand arranged immediately before the final stand is the immediately preceding stand. A thickness gauge is not arranged between the immediately preceding stand and the final stand. In other words, it is not possible to obtain the mass flow thickness of the final stand. The thickness control device includes a mass flow thickness calculation unit and a final stand thickness control unit. The mass flow thickness calculation unit calculates the mass flow thickness of the immediately preceding stand using an entry thickness actual value measured by an entry thickness gauge arranged on the entry side of the immediately preceding stand, an entry speed actual value measured by an entry speed gauge arranged on the entry side of the immediately preceding stand, and an exit speed actual value measured by an exit speed gauge arranged on the exit side of the immediately preceding stand. The final stand thickness control unit performs feedforward AGC for the final stand using the mass flow thickness calculated by the mass flow thickness calculation unit.

[0009] The second aspect has the following features in addition to the first aspect. The plate thickness control device includes a previous stand plate thickness control unit that performs feedforward AGC of the previous stand using the mass flow plate thickness calculated by the mass flow plate thickness calculation unit, and the mass flow plate thickness used in the previous stand plate thickness control unit is shifted to the final stand plate thickness control unit. In this disclosure, shifting the mass flow plate thickness means that the mass flow plate thickness calculated by the mass flow plate thickness calculation unit is input not only to the previous stand plate thickness control unit but also to the final stand plate thickness control unit. Effect of the Invention

[0010] According to the present disclosure, by implementing feedforward automatic thickness control of the final stand using the mass flow thickness at the exit of the immediately preceding stand, it is possible to eliminate the effects of work roll eccentricity that occurred in the final stand, but it is not possible to eliminate the effects of work roll eccentricity that occurred up to the immediately preceding stand. This makes it possible to control the thickness at the exit of the final stand with high accuracy, compared to implementing mass flow AGC or monitor AGC of the final stand using the actual strip speed value or actual strip thickness value at the exit of the final stand. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram for explaining the configuration of a plate thickness control device for a tandem rolling mill according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a conceptual diagram showing an example of a hardware configuration of a processing circuit of a plate thickness control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, common or corresponding elements are denoted by the same reference numerals, and descriptions thereof will be simplified or omitted.

[0013] FIG. 1 is a diagram for explaining the configuration of a plate thickness control device for a tandem rolling mill according to an embodiment.

[0014] The tandem rolling mill 1 is, for example, a tandem cold rolling mill installed in a cold rolling line. The tandem rolling mill 1 includes a plurality of rolling stands (hereinafter referred to as "stands") F1 to F6 (six in this embodiment) arranged side by side along the conveyance direction of the material 2 to be rolled. In the following, the sixth stand arranged at the end (most downstream side) of the conveyance direction of the material 2 to be rolled is referred to as the final stand F6, and the fifth stand arranged immediately before the final stand F6 is referred to as the immediately preceding stand F5.

[0015] Each of the stands F1-F6 has work rolls 11-16, speed control devices 21-26, and roll gap control devices 31-36. Taking the first stand F1 arranged at the beginning (most upstream side) in the conveying direction as an example, the first stand F1 has a pair of upper and lower first work rolls 11 that roll the material 2 to be rolled, a first speed control device 21 that controls the circumferential speed of the first work rolls 11, and a first roll gap control device 31 that controls the roll gap of the first work rolls 11. The first speed control device 21 can measure the circumferential speed of the first work rolls 11. The first roll gap control device 31 can measure the rolling load that the first work roll 11 receives from the material 2 to be rolled.

[0016] The tandem rolling mill 1 includes strip speed meters V1 to V6 and strip thickness meters X4 and X6. The strip speed meters V1 to V6 are arranged on the exit sides of the first to sixth stands F1 to F6, respectively, and measure the strip speed (conveying speed) of the material 2 to be rolled. As the strip speed meters V1 to V6 can be used with known structures, further detailed explanations are omitted. The strip speed meter V4 is arranged on the entry side of the immediately preceding stand F5 and measures the strip speed on the entry side of the immediately preceding stand F5, so it is also called the "entry side strip speed meter." The strip speed meter V5 arranged on the exit side of the immediately preceding stand F5 measures the strip speed on the exit side of the immediately preceding stand F5, so it is also called the "exit side strip speed meter." The strip speed measured by the strip speed meter V4 is also called the "entry side strip speed actual value," and the strip speed measured by the strip speed meter V5 is also called the "exit side strip speed actual value."

[0017] The thickness gauges X4 and X6 measure the thickness of the material 2 to be rolled. As the thickness gauges X4 and X6 can have a known structure, further detailed explanation is omitted. The thickness gauge X4 measures the thickness on the entry side of the immediately preceding stand F5, and corresponds to the "entry side thickness gauge" in the claims. The thickness measured by the thickness gauge X4 is also called the "entry side thickness actual value."

[0018] In addition, the tandem cold rolling mill 1 does not have a thickness gauge installed on the inlet side of the final stand F6, i.e., between the immediately preceding stand F5 and the final stand F6. In other words, it is not possible to obtain the mass flow thickness on the outlet side of the final stand F6.

[0019] The plate thickness control device 4 according to this embodiment is applied to the above-mentioned tandem rolling mill 1. The plate thickness control device 4 controls the plate thickness of the material 2 being rolled by the tandem rolling mill 1. The plate thickness control device 4 includes a mass flow plate thickness calculation unit 41, a previous stand plate thickness control unit 42, and a final stand plate thickness control unit 43.

[0020] The mass flow thickness calculation unit 41 calculates the actual inlet thickness value h measured by the inlet thickness meter X4 arranged on the inlet side of the immediately preceding stand F5. 4,ACT and the actual entry strip speed V measured by the entry strip speed meter V4 located on the entry side of the immediately preceding stand F5. 4,ACT and the actual exit strip speed V measured by the exit strip speed meter V5 located on the exit side of the immediately preceding stand F5. 5,ACT The mass flow thickness calculation unit 41 receives the inlet thickness actual value h 4,ACT , Actual inlet plate speed V 4,ACT and the actual exit plate speed V 5,ACT According to the law of constant mass flow, the mass flow plate thickness h at the outlet of the previous stand F5 is calculated. 5,MF Calculate the mass flow plate thickness h including the law of constant mass flow 5,MF The calculation method is well known, so a detailed description will be omitted here.

[0021] The immediately preceding stand thickness control unit 42 calculates the mass flow thickness h of the immediately preceding stand F5 at the outlet side calculated by the mass flow thickness calculation unit 41. 5,MF The feedforward AGC of the immediately preceding stand F5 is performed using the calculated mass flow thickness h 5,MF At least one of the fifth speed control device 25 and the fifth reduction control device 35 is feedforward controlled so that the difference (thickness deviation) between the target thickness value on the delivery side of the immediately preceding stand F5 approaches zero. As a result, at least one of the plate speed in the immediately preceding stand F5 and the roll gap of the fifth work roll 15 is manipulated (changed). As a specific manipulation method, a known method can be used, and therefore further detailed description will be omitted.

[0022] In this embodiment, the mass flow plate thickness h calculated by the mass flow plate thickness calculation unit 41 is 5,MF is inputted not only to the immediately preceding stand thickness control unit 42 but also to the final stand thickness control unit 43 (shifted).

[0023] The final stand thickness control unit 43 is a mass flow thickness h 5,MF The final stand thickness control unit 43 performs feedforward AGC for the final stand F6 using the mass flow thickness h 5,MF At least one of the sixth speed control device 26 and the sixth reduction control device 36 is controlled so that the difference (thickness deviation) between the target thickness value at the delivery side of the final stand F6 approaches zero. As a result, at least one of the plate speed in the final stand F6 and the roll gap of the sixth work roll 16 is manipulated (changed). As a specific manipulation method, a known method can be used, and therefore further detailed description will be omitted.

[0024] Here, the mass flow plate thickness h at the outlet of the previous stand F5 5,MF is affected by the eccentricity of the first to fifth work rolls 11-15 up to the immediately preceding stand F5. However, the feedforward AGC of the final stand F6 by the final stand thickness control unit 43 cannot eliminate the effects of the eccentricity of the sixth work roll 16 that occurs in the final stand F6, but it can eliminate the effects of the eccentricity of the first to fifth work rolls 11-15 up to the immediately preceding stand F5.

[0025] Next, a specific structure of the plate thickness control device 4 will be described. The specific structure of the plate thickness control device 4 is not limited, but may be as follows as an example. FIG. 2 is a conceptual diagram showing an example of the hardware configuration of the processing circuit of the plate thickness control device 4. The mass flow plate thickness calculation unit 41, the immediately preceding stand plate thickness control unit 42, and the final stand plate thickness control unit 43 indicate some of the functions of the plate thickness control device 4, and each function is realized by the processing circuit. For example, the processing circuit includes at least one processor 401 and at least one memory 402. For example, the processing circuit includes at least one dedicated hardware 403. As a specific example, the processing circuit is a PLC (Programmable Logic Controller).

[0026] When the processing circuit includes a processor 401 and a memory 402, each function of the plate thickness control device 4 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is described as a program. At least one of the software and firmware is stored in the memory 402. The processor 401 realizes each function by reading and executing the program stored in the memory 402. The processor 401 is also called a CPU (Central Processing Unit), central processing unit, processing device, arithmetic unit, microprocessor, microcomputer, or DSP. For example, the memory 402 is a non-volatile or volatile semiconductor memory such as a RAM, ROM, flash memory, EPROM, or EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, or the like.

[0027] When the processing circuitry includes dedicated hardware 403, the processing circuitry may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. For example, each function is realized by a processing circuit. For example, each function is realized collectively by a processing circuit. Also, each function may be realized partially by dedicated hardware 403 and the other part by software or firmware. In this way, the processing circuitry realizes each function by hardware 403, software, firmware, or a combination thereof.

[0028] As described above, according to this embodiment, the mass flow plate thickness h 5,MF By performing feedforward AGC for the final stand F6 using this, although it is not possible to eliminate the effect of eccentricity of the sixth work roll 16 that occurs in the final stand F6, it is possible to eliminate the effect of eccentricity of the first to fifth work rolls 11-15 that occurred up to the immediately preceding stand F5. Therefore, it is possible to control the strip thickness at the exit of the final stand F6 with high accuracy, compared to the case where mass flow AGC or monitor AGC for the final stand F6 is performed using the actual strip speed value and actual strip thickness value measured by the strip speed meter V6 and strip thickness meter X6 at the exit of the final stand F6.

[0029] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, in the above embodiments, a tandem cold rolling mill installed in a cold rolling line has been described as an example of the tandem rolling mill 1, but it may be installed in a hot rolling line.

[0030] In addition, when the number, quantity, amount, range, etc. of each element is mentioned in the above embodiment, the present disclosure is not limited to the mentioned number unless otherwise specified or clearly specified in principle. For example, the number of stands is not limited to six, but may be at least two. Furthermore, the structures, etc. described in the above embodiment are not necessarily essential to this invention unless otherwise specified or clearly specified in principle. [Explanation of symbols]

[0031] Reference Signs List 1... Tandem rolling mill, 2... Material to be rolled, F1 to F6... Rolling stands, F5... 5th stand, previous stand, F6... 6th stand, final stand, V4... Entry thickness gauge, V4... Entry plate speed gauge, V5... Exit plate speed gauge, 4... Plate thickness control device, 41... Mass flow plate thickness calculation unit, 42... Previous stand plate thickness control unit, 43... Final stand plate thickness control unit

Claims

1. A plate thickness control device for a tandem rolling mill that controls the plate thickness of a material to be rolled by a tandem rolling mill having a plurality of rolling stands, Each rolling stand has a work roll, the rolling stand arranged at the end in the conveying direction of the rolled material is defined as a final stand, the rolling stand arranged immediately before the final stand is defined as an immediately preceding stand, and no thickness gauge is provided between the immediately preceding stand and the final stand, a mass flow thickness calculation unit that calculates a mass flow thickness of the immediately preceding stand using an actual entry thickness value measured by an entry thickness gauge arranged on the entry side of the immediately preceding stand, an actual entry plate speed value measured by an entry plate speed meter arranged on the entry side of the immediately preceding stand, and an actual exit plate speed value measured by an exit plate speed meter arranged on the exit side of the immediately preceding stand; A final stand thickness control unit that performs feedforward AGC of the final stand using the mass flow thickness calculated by the mass flow thickness calculation unit; A plate thickness control device for a tandem rolling mill comprising the above-mentioned.

2. The plate thickness control device for a tandem rolling mill according to claim 1, A previous stand thickness control unit performs feedforward AGC of the previous stand using the mass flow thickness calculated by the mass flow thickness calculation unit, The mass flow thickness used in the immediately preceding stand thickness control unit is shifted to the final stand thickness control unit.

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