JPH06122011A - Cold rolling mill control method - Google Patents

Abstract

(57) [Summary] [Purpose] Continuous cold work that enables improvement in efficiency and yield by calculating downtime due to welding work on the entrance side of the rolling mill and setting and controlling the optimum rolling speed. A method for controlling a rolling mill is provided. [Structure] The front end and the rear end of the metal strip material are connected by a welding process and delivered to a looper, and the metal strip material stored in the looper is continuously delivered to a cold rolling mill for rolling. In the control method of the cold rolling mill of the formula, before welding, the material information of the metal strip material is tracked, the welding time required for the welding process consisting of a plurality of processes is calculated based on the information, and the looper The rolling speed of the cold rolling mill is determined from the storage amount and the welding time, and the rolling speed of the rolling mill is controlled based on the rolling speed. Then, 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 storage amount of the looper at that time and the time required for the remaining welding process, and based on the rolling speed. Control the rolling speed of the rolling mill.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a leading end and a trailing end of a metal strip material are connected by a welding process and delivered to a looper, and the metal strip material stored in the looper is continuously fed to a cold rolling mill. TECHNICAL FIELD The present invention relates to a control method for a totally continuous cold rolling mill that feeds and rolls the material continuously, and particularly to a control method for the rolling speed.

[0002]

2. Description of the Related Art As is well known, a fully continuous cold rolling mill is capable of running through a strip for each coil by welding a metal strip material at the entrance side of the rolling mill to form a single steel sheet. Instead, the metal strip material is continuously rolled, and there are advantages that the off-gauge length is reduced and the yield is improved. The fully continuous cold rolling mill is equipped with a looper for the purpose of preventing the rolling mill from stopping during welding of metal strip material. Conventionally, a flash butt welding machine has been used as the welding machine of the rolling mill, and the welding time is almost constant even if the type of the metal strip material is changed.Therefore, the rolling speed of the rolling mill is set only by the storage amount of the looper. I should have decided in consideration.

However, in recent years, the need for rolling various kinds of metal strip materials has increased, and a welding machine using a laser beam welder has become indispensable. The welding time of this laser beam welder varies greatly depending on the plate width, material, etc. Also, depending on the metal strip material, various processes such as post-annealing, bead grinder, puncher, etc. are disturbed by the end of the welding work, and the welding time significantly changes from 90 seconds to 360 seconds, and the rolling speed of the rolling mill is set. Also calculated with the maximum value, leading to a significant decrease in efficiency.

On the other hand, in Japanese Patent Laid-Open No. 2-70313, the stop time due to welding on the entrance side of the looper is calculated in consideration of whether or not each step of the work on the entrance side of the looper has been completed, and stripping is stopped. A method has been proposed in which the rolling speed is determined by predicting the strip running pattern from the time, the high-speed steady rolling speed, and the looper storage amount. Further, in JP-A-3-28330, the maximum central section speed is calculated from the predicted value of the stop or low speed operation time of the entry or exit section and the monitored value of the storage amount of the entry or exit looper. Has proposed a method of avoiding line stoppage due to extension of welding time and the like.

Further, in Japanese Patent Laid-Open No. 3-128121, a lot manufacturing specification for predicting a shear welder welding time on the input side, a frequency of occurrence of quality defects on the central part, a payout pitch to the next process on the output side, and the like. , Learning the calculation parameters of the mathematical model that considers lot-to-lot specification differences, operator skill, etc., and extracting each data group from the past operation result data group, and calculating the error between the mathematical model calculation results and the actual results. There has been proposed a method of avoiding an unnecessary midway stop of the central portion by processing and correcting the calculation parameter table based on the result to improve accuracy.

[0006]

In the method of welding the metal strip material on the inlet side of the cold rolling mill, storing it in the looper and continuously rolling it by the rolling mill, the time required for welding the metal strip material is There is no big change in the conventional flash butt welding machine, but in the laser beam welder, it will be greatly different due to the following factors. 1) Welding time varies significantly depending on the plate width. 2) Welding time varies significantly depending on the plate thickness. 3) Welding time varies significantly depending on the plate quality. 4) A beat grinder process is required due to the difference in plate thickness. 5) A beat grinder process is required depending on the material. 6) The notcher process is required due to the difference in plate width. 7) A post-annealing process is required depending on the material. 8) Depending on the material, it is necessary to secure the welding strength, such as the use of wire and extra welding, to withstand rolling. In this way, the welding process changes depending on the material and size (plate thickness and plate width) of the metal strip material, and the welding time is 9
It greatly changes from 0 seconds to 360 seconds, there is a limit to the storage of the looper, the efficiency of the cold rolling mill decreases when the welding time is short, and the off gauge is generated when the cold rolling mill is stopped when the welding time is long. However, the yield was low.

On the other hand, the above-mentioned Japanese Patent Laid-Open No. 2-70313.
In the methods proposed in Japanese Patent Laid-Open No. 28330/1993 and Japanese Patent Laid-Open No. 28330/1990, it is good if the welding time is stable as in a flash butt welding machine, but if there is a large change such as in a laser beam welder, an error will occur. It was very inappropriate. Further, with the method proposed in Japanese Patent Laid-Open No. 3-128121, it is impossible to accurately predict the downtime due to the welding work for each coil, and it is not possible to perform appropriate control.

The present invention has been made to solve the above-mentioned conventional problems, and calculates the downtime due to the welding operation on the entrance side of the 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 and yield of the cold rolling mill by setting and controlling an optimum rolling speed.

[0009]

A method for controlling a cold rolling mill according to the present invention comprises a welding machine installed on the inlet side of a cold rolling mill to connect the leading end and the trailing end of a metal strip material by a welding process. Then, the metal strip material stored in the looper is continuously fed into the cold rolling mill to be rolled, and the following steps are included in the control method of the fully continuous cold rolling mill. (1) Before welding, the material information of the metal strip material is tracked, the welding time required for the welding process consisting of a plurality of processes is calculated based on the information, and the cooling amount is calculated from the storage amount of the looper and the welding time at that time. The step of 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, and the rolling speed is determined. Based on the process of controlling the rolling speed of the cold rolling mill.

[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 the welding, the storage amount of the loop car and the time required for the welding process (for each process) The optimum rolling speed is determined based on (sum of time). Then, in the second stage, every time one of the welding processes is completed, the optimum rolling speed is determined again based on the storage amount of the looper at that time and the time required for the remaining welding process. This is because each processing operation of the welding process may change and is corrected. For example, even if the post-annealing process is performed for a significantly different amount of time, the looper's storage capacity at that time and the time required for the remaining welding process should be taken into consideration. Therefore, the rolling speed is calculated from the relationship with, and therefore, the situation of stopping the rolling mill does not occur. Therefore, an appropriate rolling speed can always be obtained, continuous rolling can be 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 its associated equipment for carrying out the embodiment. . In FIG. 4, payoff reels 1a and 1b
A metal strip material is sent out from the metal strip material, and the metal strip material is processed by a welding machine 2, a notcher / puncher 3 and a bead grinder 4 as needed, 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, and the metal strip material 8 is rolled by the cold rolling mill 6 and then edged by a flying shear 7 to wind on carrousel type tension reels 9a and 9b. Taken. The computer 10 calculates the calculation result and the like from the rolling control device 1
1 and the welding control device 12, 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 work is completed, the computer 10
Instructs the welding machine controller 12 of the plate thickness and plate width of the preceding material, the material code and the plate thickness of the following material, and the plate material code for the next welding preparation (S1). The welding machine controller 12 determines the welding conditions and the working process based on the instructed plate thickness and plate width and the material code. First, the bead speed is determined from the plate thickness and the material code, and the welding time A is obtained 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 from the material code whether post-annealing is performed (S3),
When post-annealing is performed, the post-annealing time B is obtained from the heating time and the holding time (B = heating time + holding time) (S4). Next, it is judged from the plate width and the instruction of the calculator 10 whether or not the processing by the notcher / puncher 3 is to be performed (S5). The puncher time C is obtained (C = conveyance time + device operation time). Next, it is judged from the plate thickness and the material code whether or not to process by the bead grinder 4 (S7),
When processing by the bead grinder 4, the beat grinder time D is calculated based on the grindstone speed, the plate width and the conveying time (D = (grinding wheel speed × plate width) + conveying 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 the time X required for welding, and this time X is instructed to the rolling mill controller 11 (S10).

Next, when deceleration for welding is started (S
11), the rolling speed is obtained 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 second stage control is performed.

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 +
It is calculated by α). Next, it is judged whether or not post-annealing is performed (S15), and when the post-annealing is completed and the processing is completed (S15), the rolling speed is corrected again here (S18). The corrected rolling speed is rolling speed = current storage amount of looper / (C + D +
It is calculated by E + α).

Subsequently, it is judged whether or not the processing by the notcher / puncher 3 is performed (S18), and when the processing by the notcher / puncher 3 is completed and the processing is completed (S19), the rolling speed is again set here. Correct (S20). The corrected rolling speed is obtained by rolling speed = current storage amount of looper / (D + E + α). Next, it is judged whether or not the processing by the bead grinder 4 is performed (S21), and when the processing by the notcher / puncher 3 is completed and the processing is completed (S19), the rolling speed is corrected again here (S2).
0). The corrected rolling speed is obtained by rolling speed = current storage amount of looper / (D + E + α). Next, it is determined whether or not there is processing by the bead grinder 4, and when the processing by the bead grinder 4 is completed and the processing is completed (S22), then it is determined whether or not the inspection of the welding point is completed. (S23), the input side of the cold rolling mill 6 is accelerated (S24), it is determined whether the loop car and the rolling mill can be accelerated (S25), and if possible, the rolling speed is accelerated to a speed at which rolling is possible. (S26). As a result of correcting the rolling speed, the amount of change is ± 30 mp
When it is less than m, the rolling speed is not corrected to prevent the plate thickness variation during acceleration / deceleration.

[0016]

As described above, according to the present invention, the optimum rolling speed is determined because the rolling speed of the rolling mill is calculated based on the storage amount of the looper and the welding time or the time required for the remaining welding process. The obtained product can be continuously rolled without stopping the cold rolling mill. As a result, high efficiency, high yield, high production can be achieved, and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart (No. 1) showing a control method for a cold rolling mill according to an embodiment of the present invention.

FIG. 2 is a flowchart (No. 2) showing the control method of the cold rolling mill according to the embodiment.

FIG. 3 is a flowchart (No. 3) showing the control method of the cold rolling mill according to the embodiment.

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

[Explanation of symbols]

 1a Payoff reel 1b Payoff reel 2 Welder 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 Rolling machine controller 12 Welder controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Ikeuchi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A front end and a rear end of a metal strip material are connected by a welding process and delivered to a looper, and the metal strip material stored in the looper is continuously delivered to a cold rolling mill for rolling. In the control method for a fully continuous cold rolling mill, the material information of the metal strip material is tracked before welding, and the welding time required for the welding process consisting of multiple processes is calculated based on that information. The process of 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 rolling speed, and the degree of completion of each welding process of the metal strip material. The process of determining the speed of the cold rolling mill from the storage amount of the looper at that time and the time required for the remaining welding treatment, and controlling the rolling speed of the rolling mill based on the rolling speed. Method of controlling a rolling mill.