Winding control method in a continuous rolling line
The winding control method stabilizes tension reel operations by controlling peripheral speed and current limits to reduce sudden torque and tension fluctuations, preventing plate breaks and thickness variations.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2024-11-19
- Publication Date
- 2026-05-29
AI Technical Summary
Existing methods for winding rolled materials onto tension reels in continuous rolling lines fail to adequately reduce sudden tension fluctuations, leading to potential plate breaks or thickness variations due to sudden torque increases.
A winding control method where the tension reel's peripheral speed is controlled to be significantly higher than the material's running speed by a predetermined ratio, with a current limit set based on the speed difference, and transitioning to tension control when the speed difference falls below a threshold.
Reduces sudden torque increases and tension fluctuations, preventing plate breaks and thickness variations by regulating motor current and switching to tension control when synchronized.
Smart Images
Figure 2026088768000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a winding control method in a continuous rolling line, particularly a control method when winding the tip of a rolled material around a tension reel.
Background Art
[0002] In a continuous rolling line provided with a tension reel on the outlet side of a rolling mill train, a rolled material (steel plate) rolled by the rolling mill is wound into a coil by the tension reel. Generally, when winding the tip of the rolled material around the tension reel, in order to stably wind the rolled material around the tension reel, the peripheral speed control of the tension reel is performed. Specifically, the peripheral speed of the tension reel is increased at an acceleration rate called the lead rate with respect to the running speed of the rolled material, and then the winding of the rolled material is started. That is, at the start of winding the rolled material, the peripheral speed of the tension reel is larger than the running speed of the rolled material by the amount multiplied by the lead rate. After the tip of the rolled material is wound around the tension reel, the control is switched from the peripheral speed control to the tension control, and the rolled material is wound while keeping the tension of the rolled material in a predetermined state. The tension control is generally performed by controlling the current value of the motor that drives the tension reel.
[0003] However, immediately after the start of winding the rolled material around the tension reel, due to the fact that the peripheral speed of the tension reel is increased compared to the running speed of the rolled material, the torque of the tension reel increases and a large tension is suddenly applied to the rolled material. As a result, when the thickness of the rolled material is small, this sudden tension fluctuation (spike tension) may cause the plate to break or cause a thickness variation in the plate. On the other hand, in Patent Document 1 below, a tension reel peripheral speed control is described in which the peripheral speed of the tension reel is made smaller than the running speed of the rolled material before the start of winding, and the peripheral speed of the tension reel is gradually increased after the start of winding.
Prior Art Documents
Patent Documents
[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-155835 [Overview of the project] [Problems that the invention aims to solve]
[0005] While the tension reel peripheral speed control described in Patent Document 1 above is thought to be able to suppress the occurrence of sudden tension fluctuations immediately after the start of winding of the rolled material, there is no track record of this tension reel peripheral speed control being able to sufficiently reduce sudden tension fluctuations. The present invention has been made in view of the above problems, and its purpose is to provide a winding control method in a continuous rolling line that can reduce sudden tension fluctuations immediately after the start of winding the rolled material onto the tension reel. [Means for solving the problem]
[0006] To achieve the above objective, a winding control method in a continuous rolling line according to one aspect of the present invention is a winding control method in a continuous rolling line in which a rolled material is wound by a tension reel provided on the exit side of a rolling mill, wherein when winding the leading edge of the rolled material onto the tension reel, the peripheral speed of the tension reel is controlled to be significantly larger than the running speed of the rolled material by a predetermined ratio, and the current value of the motor driving the tension reel is regulated by a current upper limit value corresponding to the speed difference between the peripheral speed of the tension reel and the running speed of the rolled material.
[0007] Furthermore, a further aspect of the present invention is characterized in that the speed difference between the running speed of the rolled material and the peripheral speed of the tension reel is calculated when the leading edge of the rolled material is wound onto the tension reel, and the larger the speed difference, the smaller the current upper limit is set. Furthermore, a further aspect of the present invention is characterized in that, when the thickness of the rolled material is less than a predetermined value, and the speed difference is greater than a predetermined value, the current upper limit is set to be smaller than the predetermined value compared to when the thickness is greater than a predetermined value.
[0008] Furthermore, a further aspect of the present invention is characterized in that, when the speed difference is below a threshold at which the peripheral speed of the tension reel and the running speed of the rolled material can be considered to be synchronized, the control is switched from peripheral speed control of the tension reel to tension control of the rolled material. [Effects of the Invention]
[0009] In this invention, the sudden increase in torque of the tension reel immediately after the start of winding the rolled material onto the tension reel can be reduced, thereby reducing the sudden tension fluctuations of the rolled material immediately after the start of winding. [Brief explanation of the drawing]
[0010] [Figure 1] This is a schematic diagram of the outlet portion showing one embodiment of a continuous rolling line to which the winding control method of the present invention is applied. [Figure 2] This is a time-series data example showing the tension reel torque and the thickness of the rolled material immediately after the start of winding the rolled material onto the tension reel. [Figure 3] This is time-series data showing another example of tension reel torque and sheet thickness of the rolled material immediately after winding of the rolled material onto the tension reel begins. [Figure 4] This is a conceptual diagram illustrating the winding control method performed by the control device shown in Figure 1. [Figure 5] This is a flowchart showing the calculation process for the winding control method performed by the control device in Figure 1. [Figure 6] This is the control table used in the calculation process shown in Figure 5. [Figure 7] This is time-series data used to explain the operation of the calculation process shown in Figure 5. [Modes for carrying out the invention]
[0011] The following describes in detail an embodiment of a winding control method in a continuous rolling line with reference to the drawings. The embodiments shown below are illustrative of devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited to the embodiments described below.
[0012] Figure 1 is a schematic diagram of the exit section showing one embodiment of a continuous rolling line to which a winding control method is applied. In Figure 1, multiple rolling mills 1A to 1D are arranged in a straight line along the line, forming a continuous rolling line for steel plates (material to be rolled) S. The steel plates S are passed from left to right in Figure 1, and a tension reel 5 is positioned at the exit of the final stand rolling mill 1D, sandwiching a steel plate cutting machine 2, a deflector roll 3, and a retaining roll 4. In this device, two tension reels 5 are made up of two mandrels, and these alternately wind the steel plates S fed from the final stand rolling mill 1D. The tension reels 5 are also equipped with speed sensors 8 that detect the rotational speed of the tension reels 5. The configuration of the tension reels 5 themselves is conventional, so a detailed explanation is omitted. In the following explanation, the process of winding the tip of the steel plate S onto the tension reel 5 from a state where the tip of the steel plate S in the feeding direction (hereinafter simply referred to as the tip) is not wound onto the tension reel 5 will be referred to as winding the steel plate S or the wrapping of the steel plate S. Furthermore, the process of winding the tip of the steel plate S onto the coil after it has been wound onto the tension reel 5 will be referred to as winding the steel plate S.
[0013] Each tension reel 5 is rotationally driven by a motor M. The peripheral speed of the tension reel 5 can be controlled by the magnitude of the current applied to the motor M. Similarly, the tension of the steel plate S by the tension reel 5 can be controlled by the torque of the tension reel 5, and the torque of the tension reel 5 can also be controlled by the magnitude of the applied current. As will be described later, in this embodiment, when winding the steel plate S onto the tension reel 5, the applied current of the motor M is controlled so that the tension of the steel plate S reaches a predetermined tension. Also, when winding the tip of the steel plate S onto the tension reel 5, the applied current of the motor M is controlled so that the peripheral speed of the tension reel 5 reaches a predetermined peripheral speed. In effect, before and during winding the tip of the steel plate S onto the tension reel 5, once the peripheral speed of the tension reel 5 reaches a predetermined peripheral speed, the current value of the motor M becomes small because it consumes only the mechanical torque. The applied current of the motor M is controlled by the control device 6 of the tension reel 5. The control device 6 is configured with an integrated computer system and has advanced arithmetic processing capabilities, similar to a general computer system. The computer system consists not only of a processing unit but also of a memory device for storing programs and various data, and input / output devices for sending and receiving information and signals. This control device 6 is networked with other computer systems in the rolling line, and through this network, it can acquire specifications such as the thickness and width of the steel sheet S being wound onto the tension reel 5. From the network, it can also acquire, for example, the preset sheet speed of the continuous rolling line, i.e., the travel speed of the steel sheet S.
[0014] Next, we will explain the torque of the tension reel 5 and the thickness of the steel plate S at the start of winding the tip of the steel plate S onto the tension reel 5. Figure 2 shows the change in torque of the tension reel 5 and the thickness over time when winding the tip of the steel plate S onto the tension reel 5 is performed normally. In this embodiment, at the start of winding the tip of the steel plate S onto the tension reel 5, the peripheral speed of the tension reel 5 is increased in advance by a predetermined ratio relative to the running speed of the steel plate S. This ratio is called the lead ratio, and therefore the peripheral speed of the tension reel 5 before winding the steel plate is (1 + lead ratio) × steel plate running speed. Also, the speed difference between the peripheral speed of the tension reel 5 and the running speed of the steel plate S before winding is the lead ratio × steel plate running speed. Winding of the steel plate S onto the tension reel 5 is started with this speed difference. On the other hand, Figure 3 shows the change in torque of the tension reel 5 and the thickness over time when spike tension occurs and the thickness of the steel plate S decreases when the leading edge of the steel plate S is wound onto the tension reel 5. This thickness fluctuation can be explained as follows. That is, since the peripheral speed of the tension reel 5 is greater than the running speed of the steel plate S by the lead ratio, the tension of the steel plate S becomes excessively high between the final cold rolling stand and the tension reel 5 when the leading edge of the steel plate S is wound onto the tension reel 5 (spike tension). As a result, the forward tension at the final cold rolling stand increases, and the rolling load in the roll bite decreases sharply. Because the rolling load decreases in this way, the mill elongation decreases, and the thickness of the plate decreases. Therefore, the spike tension can be reduced by reducing the amount of torque increase of the tension reel 5 caused by the winding of the steel plate S onto the tension reel 5.
[0015] In this embodiment, in the time domain from the start of winding the steel plate S onto the tension reel 5 to the beginning of winding, an effort was made to reduce the amount of increase in torque of the tension reel 5 that increases simultaneously with the winding of the steel plate S. That is, as shown in Figure 4, when the peripheral speed of the tension reel 5 is large compared to the travel speed of the steel plate S, the upper limit of the current of the motor M that rotates the tension reel 5 is set to a small value. In the figure, the maximum speed difference between the peripheral speed of the tension reel 5 and the travel speed of the steel plate S is the lead ratio × steel plate travel speed mentioned above. Then, when the steel plate S begins to wind onto the tension reel 5, the speed difference between the two decreases rapidly. The upper limit of the current of the motor M is increased in accordance with this decrease in speed difference. As described above, after the steel plate S is wound onto the tension reel 5, the steel plate S is wound while controlling the torque of the motor M so that the tension of the steel plate S becomes a predetermined tension. If the predetermined tension at this time is T, the torque of the motor M is t, and the winding radius (coil radius) of the steel plate S is D, then T = t / D. Since the torque t of motor M is proportional to the current applied to motor M, the current applied to motor M is controlled so that a predetermined torque is obtained. The switch from winding the tip of the steel plate S to winding up the steel plate S is performed when the speed difference between the travel speed of the steel plate S and the peripheral speed of the tension reel 5 falls below a threshold.
[0016] The outline of the setting of the above speed difference and the upper limit value of the current of the motor M during the winding of the tip of the steel plate S is shown in Table 1 below. The upper limit value of the current of the motor M can be set according to the specifications of the steel plate S, that is, the plate width w and the plate thickness t. In this embodiment, the plate width w is all 820 mm or more and does not become a parameter of the upper limit value of the current of the motor M. On the other hand, for the plate thickness t, for example, when the speed difference is 60% in terms of the lead ratio, when 0.40 mm ≦ t < 0.65 mm, the upper limit value of the current of the motor M is set to 80% in terms of the motor rated current value ratio. Also, when 0.65 mm ≦ t < 1.15 mm, the upper limit value of the current of the motor M is set to 60% in terms of the motor rated current value ratio, and when 1.15 mm ≦ t, the upper limit value of the current of the motor M is set to 50% in terms of the motor rated current value ratio. Also, when the speed difference is 100% in terms of the lead ratio, when 0.40 mm ≦ t < 0.65 mm and 0.65 mm ≦ t < 1.15 mm, the upper limit value of the current of the motor M is set to 12% in terms of the motor rated current value ratio, and when 0.65 mm ≦ t < 1.15 mm and 1.15 mm ≦ t, the upper limit value of the current of the motor M is set to 15% in terms of the motor rated current value ratio. Actually, the control table of FIG. 6 described later is used. Summarizing the whole, when the speed difference is large, the upper limit value of the motor current is set small, the smaller the speed difference, the larger the upper limit value of the motor current is set, and when the speed difference is large and the plate thickness is small, the upper limit value of the motor current is set even smaller.
[0017]
Table 1
[0018] Next, the calculation process of the tension reel 5 - based steel sheet winding control executed in the control device 6, particularly the winding start control of the tip of the steel sheet S onto the tension reel 5, will be described using the flowchart of FIG. 5. Note that the start of winding the steel sheet S onto the tension reel 5 is executed along with the completion of cutting the steel sheet S. This calculation process is executed, for example, by a cutting start command of the steel sheet S. First, in step S1, the steel sheet specifications (thickness and width) are read from the network of the rolling line. Next, it proceeds to step S2, and the running speed of the steel sheet S is read from the network or the result of individual calculation processing in the control device 6. Next, it proceeds to step S3, and according to individual calculation processing not shown, the peripheral speed control of the tension reel 5 is performed. This peripheral speed control of the tension reel 5 is a control that increases the peripheral speed of the tension reel 5 by the lead rate with respect to the running speed of the steel sheet S. The peripheral speed of the tension reel 5 is calculated by multiplying the rotational speed of the tension reel 5 detected by the speed sensor 8 by the outer diameter of the tension reel 5, that is, the winding radius of the steel sheet S. Then, the applied current of the motor M that drives the tension reel 5 is adjusted to perform a speed increase control such that the peripheral speed of the tension reel 5 is increased by the lead rate compared to the steel sheet running speed. Note that the applied current of the motor M at this time is regulated by the aforementioned or the motor current upper limit value to be described later. However, as described above, before the start of winding the steel sheet S, it is necessary to make the peripheral speed of the tension reel 5 larger than the running speed of the steel sheet S by the lead rate. Therefore, until then, it is assumed that the applied current of the motor M is not regulated by the motor current upper limit value.
[0019] Next, the process moves to step S4, where the peripheral speed of the tension reel 5 calculated in step S3 is read. Next, the process moves to step S5, where the speed difference is calculated by subtracting the running speed of the steel plate S from the peripheral speed of the tension reel 5. Next, the process moves to step S6, where the upper limit of the motor M current is calculated according to the speed difference and steel plate specifications, according to individual calculation processes not shown. Specifically, the upper limit of the motor M current is set according to the control table in Figure 6. Figure 6 shows the upper limit of the motor M current (motor rated current value ratio) according to the speed difference (lead ratio) for each plate thickness in sequence. As mentioned above, the upper limit of the motor M current is set to a smaller value when the speed difference is large, and to a larger value as the speed difference decreases. Next, the process moves to step S7, where it is determined whether the speed difference calculated in step S5 is below a threshold. If the speed difference is below the threshold, the process moves to step S8; otherwise, the process moves to step S2. This threshold is set to a speed difference that allows the running speed of the steel plate S and the peripheral speed of the tension reel 5 to be considered synchronized, for example, a speed difference corresponding to a lead ratio of 20%. In step S8, a signal indicating that the tip winding is complete is output. Next, the process moves to step S9, where, according to individual calculation processes (not shown), the process transitions to tension current control, i.e., winding control of the steel plate S, and then returns to the previous step.
[0020] According to this calculation process, before winding of the steel plate S onto the tension reel 5 begins, the peripheral speed of the tension reel 5 is increased by the lead ratio relative to the travel speed of the steel plate S. Once winding of the steel plate S onto the tension reel 5 begins, the current applied to the motor M is restricted by a motor current upper limit value corresponding to the speed difference between the peripheral speed of the tension reel 5 and the travel speed of the steel plate S. The motor M current upper limit value is set as a value obtained by reducing the motor rated current value by a predetermined ratio. Therefore, for example, the increase in torque of the tension reel 5 when the tip of the steel plate S is wound onto the tension reel 5 (instantaneous) is reduced, thereby reducing sudden tension fluctuations (spike tension) of the steel plate S. As the peripheral speed of the tension reel 5 decreases as the steel plate S is wound onto the tension reel 5, the speed difference between the peripheral speed of the tension reel 5 and the travel speed of the steel plate S decreases rapidly. As a result, the motor M current upper limit value is set to increase as the steel plate S is wound onto the tension reel 5. When the peripheral speed of the tension reel 5 becomes approximately equal to the travel speed of the steel plate S, a signal indicating that the tip winding is complete is output, and the process transitions to winding the steel plate S, i.e., tension control.
[0021] Figure 7 shows time-series data illustrating the changes over time of the peripheral speed of the tension reel 5, the upper limit of the motor M current, the measured current value of the motor M, and the thickness of the exit plate during the winding control of the steel plate S onto the tension reel 5 using the calculation process shown in Figure 5. The reference tension reel peripheral speed is maintained at a speed increased by the lead ratio relative to the running speed of the steel plate S during the steel plate winding control. The calculation process shown in Figure 5 controls the applied current of the motor M to match this reference tension reel peripheral speed, so that the peripheral speed of the tension reel 5 matches the reference tension reel peripheral speed. Winding of the leading edge of the steel plate begins at time t1, and as mentioned above, from this point onward, the applied current of the motor M is restricted by the upper limit of the motor current. From time t1 to time t2, the speed difference between the peripheral speed of the tension reel 5 and the running speed of the steel plate S is large, so the upper limit of the motor M current is maintained at a small value. From time t2 onward, as the calculated peripheral speed of the tension reel 5 decreases, the speed difference between it and the running speed of the steel plate S becomes smaller, and consequently, the upper limit of the motor M's current is set to a gradually larger value. At time t3, the speed difference between the peripheral speed of the tension reel 5 and the running speed of the steel plate S reaches a threshold, for example, 20% in lead ratio, and the calculation process in Figure 5 switches to winding the steel plate S. Accordingly, a signal indicating that the tip winding is complete is output (turned on), and from this point onward, the process transitions to tension (current) control of the steel plate S. In this example, the thickness of the steel plate S decreases immediately after winding of the steel plate S onto the tension reel 5 begins, but this is because the scale of the vertical axis is large, and in practice, the plate thickness never fell below the lower limit.
[0022] The winding control method in a continuous rolling line according to the embodiment has been described above. However, the present invention is not limited to the configuration described in the above embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above embodiment, when winding the leading edge of the steel plate S onto the tension reel 5, the rated current value of the motor M was reduced by a predetermined rate to set an upper limit for the motor M current according to the speed difference. However, when winding the leading edge of the steel plate S onto the tension reel 5, it is sufficient to set an upper limit for the motor M current that is at least smaller than the tension control current value, so the method for setting the upper limit for the motor M current is not limited to the above.
[0023] In this embodiment, when winding the leading edge of the steel plate (rolled material) S onto the tension reel 5, the peripheral speed of the tension reel 5 is controlled to be significantly larger than the running speed of the steel plate S by a predetermined ratio (= lead ratio). In addition, the current value of the motor M that drives the tension reel 5 is regulated by a current upper limit value corresponding to the speed difference between the peripheral speed of the tension reel 5 and the running speed of the steel plate S. As a result, the increase in torque of the tension reel 5 immediately after the leading edge of the steel plate S is wound onto the tension reel 5 is reduced, thereby reducing the spike tension of the steel plate S. Consequently, plate breakage and plate thickness fluctuations during winding of the leading edge of the steel plate S onto the tension reel 5 can be avoided.
[0024] Furthermore, the speed difference between the travel speed of the steel plate S and the peripheral speed of the tension reel 5 when the tip of the steel plate S is wrapped around the tension reel 5 is calculated, and the larger this speed difference, the smaller the current upper limit is set. This effectively reduces the increase in torque of the tension reel 5 when the tip of the steel plate S begins to wrap around the tension reel 5. Furthermore, when the thickness of the steel plate S is less than a predetermined value, and the speed difference between the running speed of the steel plate S and the peripheral speed of the tension reel 5 is greater than a predetermined value, the current upper limit can be set lower than the predetermined value compared to when the plate thickness is greater than a predetermined value, thereby reliably avoiding fractures and thickness fluctuations that are likely to occur with thin steel plates S.
[0025] Furthermore, when the speed difference between the peripheral speed of the tension reel 5 and the running speed of the steel plate S is below a threshold at which the peripheral speed of the tension reel 5 and the running speed of the steel plate S can be considered synchronized, the system switches from peripheral speed control of the tension reel 5 to tension control of the steel plate S. This allows the system to transition to winding with tension control of the steel plate S from the point at which the leading edge of the steel plate S is considered to have wrapped around the tension reel 5. [Explanation of symbols]
[0026] 1A~1D Rolling Mill 2 Steel plate cutting machine 3 Deflector Roll 4. Pressing Roll 5 Tension Reels 6. Control device 8 Speed Sensor M Motor
Claims
1. A winding control method in a continuous rolling line in which a rolled material is wound up by a tension reel provided on the exit side of a rolling mill, characterized in that, when winding the leading edge of the rolled material onto the tension reel, the peripheral speed of the tension reel is controlled to be significantly larger than the running speed of the rolled material by a predetermined ratio, and the current value of the motor driving the tension reel is regulated by a current upper limit value corresponding to the speed difference between the peripheral speed of the tension reel and the running speed of the rolled material.
2. A winding control method in a continuous rolling line according to claim 1, characterized in that the speed difference between the running speed of the rolled material and the peripheral speed of the tension reel when the leading edge of the rolled material is wound onto the tension reel is calculated, and the larger the speed difference, the smaller the current upper limit is set.
3. The winding control method in a continuous rolling line according to claim 2, characterized in that when the thickness of the rolled material is less than a predetermined value and the speed difference is greater than a predetermined value, the current upper limit is set to be smaller than a predetermined value compared to when the thickness of the rolled material is greater than a predetermined value.
4. The winding control method in a continuous rolling line according to claim 2, characterized in that when the speed difference is below a threshold at which the peripheral speed of the tension reel and the running speed of the rolled material can be considered to be synchronized, the method switches from peripheral speed control of the tension reel to tension control of the rolled material.