JP2605557B2 - Control method of cold rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting a front end and a rear end of a metal strip material by a welding process and sending the metal strip material to a looper, and continuously feeding the metal strip material stored in the looper to a cold rolling mill. TECHNICAL FIELD The present invention relates to a method for controlling a continuous rolling mill in which continuous feeding and rolling are performed, and particularly to a method for controlling a rolling speed.

[0002]

2. Description of the Related Art As is well known, a cold rolling mill of a continuous type is configured to weld a metal strip material at the entry side of the rolling mill into a single steel sheet, thereby performing a through-hole removal for each coil. In this method, the metal strip material is continuously rolled without any effect, and there are advantages that the length of the off-gauge is reduced and the yield is improved. This continuous rolling mill is provided with a looper for the purpose of preventing the rolling mill from stopping when welding the metal strip material. Conventionally, a flash butt welding machine has been used as a welding machine for a rolling mill, and the welding time is almost constant even if the type of the metal strip material changes, so that the rolling speed of the rolling mill can be set only by the storage amount of the looper. It should have been decided in consideration of.

In recent years, however, the need for rolling various types of metal strip materials has increased, and a welding machine using a laser beam welder has become essential. The welding time of this laser beam welder greatly changes depending on the sheet width, material, and the like. In addition, depending on the metal strip material, various processes such as post-annealing, bead grinder, puncher, etc. are disturbed by the end of the welding operation, and the welding time greatly changes from 90 seconds to 360 seconds. Since the calculation was performed using the maximum value, the efficiency was greatly reduced.

On the other hand, in Japanese Patent Application Laid-Open No. 2-70313, a stop time due to welding on the entrance side of the looper is calculated in consideration of whether or not each operation of the operation on the entrance side of the looper is completed, and the strip stop is performed. There has been proposed a method of determining a speed of a rolling mill by predicting a strip running pattern from time, a high-speed steady rolling speed, and a storage amount of a looper. In Japanese Patent Application Laid-Open No. 3-28330, the maximum central section speed is calculated from the predicted value of the stop or low-speed operation time of the entrance or exit section and the monitored value of the storage amount of the entrance or exit looper. Thus, a method for avoiding line stoppage due to extension of welding time or the like has been proposed.

Japanese Patent Application Laid-Open No. 3-128121 discloses a lot manufacturing specification for estimating a shear welder welding time on the entrance side, a frequency of occurrence of quality defects at the center, and a delivery pitch to the next process on the exit side. , Learning the calculation parameters of the mathematical model taking into account the differences between lots, the skill of the operator, etc., extracting each data group from the past operation result data group, and calculating the error between the calculation result of the mathematical model and the actual result. There has been proposed a method of correcting the calculation parameter table based on the processing result and improving the accuracy, thereby avoiding unnecessary stoppage of the central part.

[0006]

In a method in which a metal strip material is welded at the entry side of a cold rolling mill, stored in a looper and continuously rolled by a rolling mill, the time required for welding the metal strip material is reduced. The conventional flash butt welding machine does not change much, but the laser beam welder differs greatly due to the following factors. 1) The welding time varies greatly depending on the plate width. 2) The welding time varies greatly depending on the plate thickness. 3) The welding time varies greatly depending on the plate quality. 4) A beat grinder process is required due to the difference in plate thickness. 5) Depending on the material, a beat grinder process is required. 6) Notching process is required due to the difference in plate width. 7) A post-annealing step is required depending on the material. 8) Depending on the material, it is necessary to secure the welding strength to withstand rolling such as wire use and extra metal. As described above, the welding process varies depending on the material and size (sheet thickness and sheet width) of the metal strip material, and the welding time is also 9 hours.
It changes greatly from 0 seconds to 360 seconds, and there is a limit to the storage of the looper. If the welding time is short, the efficiency of the cold rolling mill is reduced. The yield was reduced.

On the other hand, Japanese Unexamined Patent Application Publication No.
In the method proposed in Japanese Patent Application Laid-Open No. 3-283330 and Japanese Patent Application Laid-Open No. 3-28330, it is good if the welding time is stable as in a flash butt welding machine, but if the welding time is largely changed like a laser beam welder, the error is reduced. It was largely inappropriate. Further, in the method proposed in Japanese Patent Application Laid-Open No. 3-128121, it is impossible to accurately predict the downtime due to the welding operation for each coil, so that appropriate control cannot be performed.

The present invention has been made in order to solve such a conventional problem, and calculates a downtime due to a welding operation on an entrance side of a fully continuous cold rolling mill.
An object of the present invention is to provide a method for controlling a cold rolling mill, which can improve the efficiency of a cold rolling mill and improve the yield by setting and controlling an optimum rolling speed.

[0009]

According to a control method of a cold rolling mill according to the present invention, a leading end and a trailing end of a metal strip material are connected by a welding process by a welding machine installed on the entrance side of the cold rolling mill. Then, the metal strip material stored in the looper is continuously fed to a cold rolling mill, and is rolled by being continuously fed to the cold rolling mill. (1) Before welding, material information of a metal strip material is tracked, and based on the information, a welding time required for a welding process including a plurality of processes is calculated, and the welding time required for the looper storage amount and the welding time at that time is calculated. Determining the rolling speed of the cold rolling mill and controlling the rolling speed of the cold rolling mill based on the rolling speed. (2) Each time each process of the welding process of the metal strip material is completed, the rolling speed of the cold rolling mill is determined from the stored amount of the looper at that time and the time required for the remaining welding process. Controlling the rolling speed of the cold rolling mill on the basis of this.

[0010]

In the present invention, the control of the rolling speed of the cold rolling mill is divided into two stages. In the first stage, before welding, the storage amount of the loop car and the time required for the welding process (for each process) The sum of the times) is used to determine the optimum rolling speed. In the second stage, each time one of the welding processes is completed, the optimum rolling speed is determined again based on the stored amount of the looper at that time and the time required for the remaining welding process. This is for correcting each processing operation of the welding process in some cases. For example, even if the post-annealing process time is significantly different from the expected time, taking into account that fact, the looper storage amount at that time and the time required for the remaining welding process Therefore, the rolling speed is determined from the relationship described above, so that the rolling mill does not stop. Therefore, an appropriate rolling speed can always be obtained, rolling can be continuously performed without stopping the cold rolling mill, and high production with high efficiency and high yield is achieved. The present invention is particularly suitable for laser beam welding, MIG welding, TIG welding and the like.

[0011]

1 to 3 are flow charts showing a rolling method according to an embodiment of the present invention, and FIG. 4 is a block diagram showing a configuration of a control device and related equipment for carrying out the embodiment. . In FIG. 4, payoff reels 1a, 1b
, A metal strip material is sent out, and the metal strip material is processed as necessary by a welding machine 2, a notcher / puncher 3 and a bead grinder 4, and the processed metal strip material is stored in a looper 5. A cold rolling mill 6 is arranged on the exit side of the looper 5. The metal strip material 8 is rolled by the cold rolling mill 6, and then is framed by a flying shear 7 and wound around carousel-type tension reels 9 a and 9 b. Taken. The computer 10 sends the calculation result and the like to the rolling control device 1
The rolling control device 11 controls the cold rolling mill 6, and the welding control device 12 controls the welding machine 2, the notcher / puncher 3, and the bead grinder 4, respectively. Next, these controls will be described with reference to FIGS.

First, when the welding operation is completed, the computer 10
Instructs the welding machine control device 12 about the sheet thickness, the sheet width, the material code of the preceding material, the sheet thickness of the following material, and the sheet width material code in preparation for the next welding (S1). The welding machine controller 12 determines welding conditions and work processes based on the instructed sheet thickness and material code. First, the bead speed is determined from the plate thickness and the material code, and the welding time A is determined from the plate width (A = bead speed × plate thickness + β) (S2). β is the time from the start of automatic deceleration to the start of welding. Then, it is determined whether or not to perform post annealing based on the material code (S3).
When performing post-annealing, the post-annealing time B is obtained from the heating time and the holding time (B = heating time + holding time) (S4). Next, it is determined whether or not the processing by the notcher / puncher 3 is to be performed based on the sheet width and the instruction from the computer 10 (S5). The puncher time C is obtained (C = transport time + device operation time). Next, it is determined whether or not the processing is to be performed by the bead grinder 4 based on the thickness and the material code (S7).
In the case of performing the processing by the bead grinder 4, the beat grinder time D is obtained based on the grindstone speed, the plate width, and the transfer time (D = (grindstone speed × plate width and transfer time) + the transfer time).
(S8). When the processing by the bead grinder 4 is not performed, the transport time E is obtained based on the holding time and the acceleration / deceleration time (E = holding time + acceleration / deceleration time). The times A, B, C, D, and E obtained as described above are added to obtain a time X required for welding, and this time X is instructed to the rolling mill controller 11 (S10).

Next, when the deceleration for welding starts (S
11) The rolling speed is determined based on the storage amount of the looper 5 and the welding time X (rolling speed = storage amount / welding time X), and this is set in the rolling control 11 (S12). Here, the welding time X is represented by X = A + B + C + D + E + α, and α is a correction time. The cold rolling mill 6 rolls the metal strip material 8 at the set rolling speed. The above control is the first-stage control of the present invention, and then the process proceeds to the second-stage control.

When the welding is completed (S13), the rolling speed is corrected (S14). The corrected rolling speed is: rolling speed = current storage amount of looper / (B + C + D + E +
α). Next, it is determined whether or not to perform post-annealing (S15). When the post-annealing is completed and the process is completed (S15), the rolling speed is corrected again (S18). The corrected rolling speed is as follows: rolling speed = current storage amount of looper / (C + D +
E + α).

Subsequently, it is determined whether or not the processing by the notcher / puncher 3 is performed (S18). When the processing by the notcher / puncher 3 is performed and the processing is completed (S19), the rolling speed is reduced again. It is corrected (S20). The corrected rolling speed is obtained by the following formula: rolling speed = current storage amount of looper / (D + E + α). Next, it is determined whether or not the processing by the bead grinder 4 is performed (S21). When the processing by the notcher / puncher 3 is performed and the processing is completed (S19), the rolling speed is corrected again (S2).
0). The corrected rolling speed is obtained by the following formula: rolling speed = current storage amount of looper / (D + E + α). Next, it is determined whether or not the processing by the bead grinder 4 is performed. If the processing by the bead grinder 4 is completed and the processing is completed (S22), it is determined whether or not the inspection of the welding location is completed. (S23), the input side of the cold rolling mill 6 is accelerated (S24), and it is determined whether or not the loop car and the rolling mill can be accelerated (S25). (S26). In addition, as a result of correcting the rolling speed, the change amount is ± 30 mp.
When the rolling speed is less than m, the rolling speed is not corrected in order to prevent thickness fluctuation during acceleration / deceleration.

[0016]

As described above, according to the present invention, the rolling speed of the rolling mill is determined based on the storage amount of the looper and the welding time or the time required for the remaining welding process. Thus, the rolling can be continuously performed without stopping the cold rolling mill. As a result, high production with high efficiency and high yield is achieved, and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a flowchart (part 1) illustrating a method for controlling a cold rolling mill according to an embodiment of the present invention.

FIG. 2 is a flowchart (part 2) illustrating a control method of the cold rolling mill according to the embodiment.

FIG. 3 is a flowchart (part 3) illustrating a control method of the cold rolling mill according to the embodiment.

FIG. 4 is a block diagram showing a configuration of a control device for implementing the control method of the embodiment and its related equipment.

[Explanation of symbols]

 Reference Signs List 1a Payoff reel 1b Payoff reel 2 Welding machine 3 Notcher / Puncher 4 Bead grinder 5 Looper 6 Cold rolling mill 7 Flying shear 8 Metal strip material 9a Tension reel 9b Tension reel 10 Calculator 11 Roller control device 12 Welding machine control device

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Naoki Ikeuchi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (56) References JP-A-5-111708 (JP, A)

Claims (1)

(57) [Claims] 1. A front end and a rear end of a metal strip material are connected by a welding process and sent out to a looper, and the metal strip material stored in the looper is continuously fed to a cold rolling mill for rolling. In the control method of a continuous rolling mill, before welding, material information of a metal strip material is tracked, and based on the information, a welding time required for a welding process including a plurality of processes is calculated. Determining the rolling speed of the cold rolling mill from the storage amount of the looper and the welding time, controlling the rolling speed of the rolling mill based on the determined rolling speed, and determining whether the welding process of the metal strip material is completed. Determining the speed of the cold rolling mill from the storage amount of the looper and the time required for the remaining welding process at that time, and controlling the rolling speed of the rolling mill based on the rolling speed. Method of controlling a rolling mill.