US-12617009-B2 - Cold rolling mill rolling condition setting method, cold rolling method, steel sheet manufacturing method, cold rolling mill rolling condition setting device, and cold rolling mill

US12617009B2US 12617009 B2US12617009 B2US 12617009B2US-12617009-B2

Abstract

A cold rolling mill rolling condition setting method using a prediction model being generated with an explanatory variable being first multi-dimensional data obtained by transforming past rolling performance data including pre-cold rolling data of a roll material on an entry side of the cold rolling mill into multi-dimensional data, and an objective variable being post-cold rolling data of the roll material on a delivery side of the cold rolling mill, the method includes: estimating a post-rolling shape of a roll target material by inputting, to the prediction model, second multi-dimensional data generated from information including the pre-cold rolling data of the roll target material on the entry side of the cold rolling mill and a target rolling condition of the cold rolling mill; and changing the target rolling condition of the cold rolling mill such that the estimated post-rolling shape of the roll target material satisfies a predetermined condition.

Inventors

NORIKI FUJITA
Takuya Kitamura
Tetsuya Arakawa
Yoshiki IKOMA
Takumi Yamada

Assignees

JFE STEEL CORPORATION

Dates

Publication Date: 20260505
Application Date: 20220201
Priority Date: 20210621

Claims (11)

1 . A cold rolling mill rolling condition setting method, which is a method of setting a target rolling condition of a cold rolling mill when a roll target material is rolled by cold rolling using a prediction model that predicts a post-cold rolling state of the roll target material, the prediction model being generated with an explanatory variable and an objective variable, the explanatory variable being first multi-dimensional data obtained by joining past rolling performance data including pre-cold rolling data of a roll material on an entry side of the cold rolling mill in a time direction, and the objective variable being post-cold rolling data of the roll material on a delivery side of the cold rolling mill, the method comprising: estimating a post-rolling shape of the roll target material on the delivery side of the cold rolling mill by inputting, to the prediction model, second multi-dimensional data generated from information including the pre-cold rolling data of the roll target material on the entry side of the cold rolling mill and a target rolling condition of the cold rolling mill; and changing the target rolling condition of the cold rolling mill such that the estimated post-rolling shape of the roll target material satisfies a predetermined condition.
2 . The cold rolling mill rolling condition setting method according to claim 1 , wherein the pre-cold rolling data includes at least one of thickness information of the steel sheet and temperature information of the steel sheet, on the entry side of the cold rolling mill.
3 . The cold rolling mill rolling condition setting method according to claim 1 , wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet on the delivery side of the cold rolling mill.
4 . The cold rolling mill rolling condition setting method according to claim 2 , wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet on the delivery side of the cold rolling mill.
5 . A cold rolling method comprising performing a cold rolling of a roll target material using a target rolling condition of the cold rolling mill changed using the cold rolling mill rolling condition setting method according to claim 1 .
6 . A steel sheet manufacturing method comprising manufacturing a steel sheet using the cold rolling method according to claim 5 .
7 . A cold rolling mill rolling condition setting device, which is a device of setting a target rolling condition of a cold rolling mill when a roll target material is rolled by cold rolling using a prediction model that predicts a post-cold rolling state of the roll target material, the prediction model being generated with an explanatory variable and an objective variable, the explanatory variable being first multi-dimensional data obtained by joining past rolling performance data including pre-cold rolling data of a roll material on an entry side of the cold rolling mill in a time direction, and the objective variable being post-cold rolling data of the roll material on a delivery side of the cold rolling mill, the device comprising a processor comprising hardware, the processor being configured to: estimate a post-rolling shape of the roll target material on the delivery side of the cold rolling mill by inputting, to the prediction model, second multi-dimensional data generated from information including the pre-cold rolling data of the roll target material on the entry side of the cold rolling mill and a target rolling condition of the cold rolling mill; and change the target rolling condition of the cold rolling mill such that the estimated post-rolling shape of the roll target material satisfies a predetermined condition.
8 . The cold rolling mill rolling condition setting device according to claim 7 , wherein the pre-cold rolling data includes at least one of thickness information of the steel sheet and temperature information of the steel sheet, on the entry side of the cold rolling mill.
9 . The cold rolling mill rolling condition setting device according to claim 7 , wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet on the delivery side of the cold rolling mill.
10 . The cold rolling mill rolling condition setting device according to claim 8 , wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet on the delivery side of the cold rolling mill.
11 . A cold rolling mill comprising the cold rolling mill rolling condition setting device according to claim 7 .

Description

FIELD The present invention relates to a cold rolling mill rolling condition setting method, a cold rolling method, a steel sheet manufacturing method, a cold rolling mill rolling condition setting device, and a cold rolling mill. BACKGROUND When rolling a roll material such as a cold-rolled thin steel sheet with cold rolling, the rolling is to be typically performed with a stabilized sheet running property of the roll material by obtaining a good shape (or flatness) of the roll material while maintaining favorable thickness accuracy in the longitudinal direction and the width direction of the roll material. On the other hand, for the purpose of suppressing fuel consumption with reduced weight and the like, there is an increasing need for a difficult-to-roll material such as a thin hard material with a high load and a thin pre-rolling sheet thickness. During cold rolling of such a difficult-to-roll material, in order to suppress a rolling load, the difficult-to-roll material is thinned by hot rolling in a preceding step and then sent to a cold rolling step. In recent years, many of the control factors of the cold rolling mill are automatically controlled by an actuator mounted on the cold rolling mill, leading to a decreased opportunity for an operator to set the control factors of the cold rolling mill. However, at the time of cold rolling of the difficult-to-roll material as described above, the sheet crown (thickness distribution in the width direction) greatly fluctuates in the longitudinal direction in some cases. When the sheet crown has greatly fluctuated in the longitudinal direction, it is often difficult to absorb, with automatic control, fluctuations against correction of roll deflection represented by roll gap, work roll bender, intermediate roll shift, and roll expansion by thermal crown of a cold rolling mill, including a rolling load (and an accompanying calculated forward slip ratio and torque). Therefore, in such a case, the operator sets a pass schedule and a shape control actuator so as not to hinder productivity while satisfying the facility constraint of the cold rolling mill. For this reason, in recent years, the operating speed of the cold rolling mill and resultant productivity are likely to vary depending on the experience and subjectivity of the operator. In such a background, Patent Literature 1 proposes a method of performing learning of past operating conditions using a neural network and performing mill setup of a cold rolling mill using a result of the learning. In addition, Patent Literature 2 proposes a method of performing feedforward control of an edge drop using a sheet thickness profile measured on an entry side of a cold rolling mill. CITATION LIST Patent Literature Patent Literature 1: JP 6705519 BPatent Literature 2: JP 4784320 B SUMMARY Technical Problem However, with the method described in Patent Literature 1, even when the cold rolling mill has an optimum operating condition at the time of mill setup, an occurrence of fluctuation of the sheet crown in the longitudinal direction would lead to a large fluctuation in the shape of the roll material on the delivery side of the cold rolling mill. This leads to a possibility of restriction on the rolling speed due to the shape defects or an occurrence of breakage of the roll material in the worst case. On the other hand, with the method described in Patent Literature 2, the sheet thickness profile includes only one cross section in the longitudinal direction and the edge drop is predicted using a linear regression equation, making it difficult to cope with the case of fluctuation of the sheet crown in the longitudinal direction. The present invention has been made in view of the above problems, and one object is to provide a cold rolling mill rolling condition setting method and a cold rolling mill rolling condition setting device capable of setting rolling conditions for performing cold rolling with high productivity while ensuring stability of cold rolling even when rolling a difficult-to-roll material with a high load and a small pre-rolling sheet thickness. Another object of the present invention is to provide a cold rolling method and a cold rolling mill capable of performing cold rolling with high productivity while ensuring stability in cold rolling even when a difficult-to-roll material with a high load and a small pre-rolling sheet thickness is rolled with cold rolling. Still another object of the present invention is to provide a steel sheet manufacturing method capable of manufacturing a steel sheet with high yield. Solution to Problem To solve the problem and achieve the object, a cold rolling mill rolling condition setting method according to the present invention is the method of setting a target rolling condition of a cold rolling mill when a roll target material is rolled by cold rolling using a prediction model that predicts a post-cold rolling state of the roll target material, the prediction model bein