Search

EP-4309816-B1 - METHOD FOR SETTING ROLLING CONDITION FOR COLD ROLLING MILL, COLD ROLLING METHOD, METHOD FOR MANUFACTURING STEEL SHEET, DEVICE FOR SETTING ROLLING CONDITION FOR COLD ROLLING MILL, AND COLD ROLLING MILL

EP4309816B1EP 4309816 B1EP4309816 B1EP 4309816B1EP-4309816-B1

Inventors

  • FUJITA, Noriki
  • KITAMURA, TAKUYA
  • ARAKAWA, TETSUYA
  • IKOMA, Yoshiki
  • YAMADA, TAKUMI

Dates

Publication Date
20260506
Application Date
20220201

Claims (9)

  1. A cold rolling mill rolling condition setting method, which is a method of setting a target rolling condition of a cold rolling mill (1) when a roll target material (S) is rolled by cold rolling using a prediction model that predicts a post-cold rolling state of the roll target material (S), the prediction model being generated with an explanatory variable and an objective variable, the 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 (1) into multi-dimensional data, wherein the multi-dimensional data is created by a training data acquisition section (214a) and comprises an array in which a column corresponds to a width direction of the roll material and a row corresponds to a collection pitch of measurement points continuously measured in the longitudinal direction of the roll material, and the objective variable being post-cold rolling data of the roll material on a delivery side of the cold rolling mill (1), the method comprising: a step of estimating a post-rolling shape of the roll target material (S) on the delivery side of the cold rolling mill (1) by inputting, to the prediction model, second multi-dimensional data generated from information including the pre-cold rolling data of the roll target material (S) on the entry side of the cold rolling mill (1) and a target rolling condition of the cold rolling mill; and a step of changing the target rolling condition of the cold rolling mill (1) such that the estimated post-rolling shape of the roll target material (S) 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 (S) and temperature information of the steel sheet (S), on the entry side of the cold rolling mill (1).
  3. The cold rolling mill rolling condition setting method according to claim 1 or 2, wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet (S) on the delivery side of the cold rolling mill (1).
  4. A cold rolling method comprising a step of performing a cold rolling of a roll target material using a target rolling condition of the cold rolling mill (1) changed using the cold rolling mill rolling condition setting method according to any one of claims 1 to 3.
  5. A steel sheet manufacturing method comprising a step of manufacturing a steel sheet (S) using the cold rolling method according to claim 4.
  6. A cold rolling mill rolling condition setting device, which is a device of setting a target rolling condition of a cold rolling mill (1) when a roll target material (S) 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 transforming past rolling performance data including pre-cold rolling data of a roll material (S) on an entry side of the cold rolling mill (1) into multi-dimensional data, wherein the multi-dimensional data is created by a training data acquisition section (214a) and comprises an array in which a column corresponds to a width direction of the roll material and a row corresponds to a collection pitch of measurement points continuously measured in the longitudinal direction of the roll material, and the objective variable being post-cold rolling data of the roll material on a delivery side of the cold rolling mill (1), the device comprising: a means of 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 (S) on the entry side of the cold rolling mill (1) and a target rolling condition of the cold rolling mill (1); and a means of changing the target rolling condition of the cold rolling mill (1) such that the estimated post-rolling shape of the roll target material (S) satisfies a predetermined condition.
  7. The cold rolling mill rolling condition setting device according to claim 6, wherein the pre-cold rolling data includes at least one of thickness information of the steel sheet (S) and temperature information of the steel sheet (S), on the entry side of the cold rolling mill (1).
  8. The cold rolling mill rolling condition setting device according to claim 6 or 7, wherein the post-cold rolling data includes shape parameters calculated from the shape of the steel sheet (S) on the delivery side of the cold rolling mill (1).
  9. A cold rolling mill comprising the cold rolling mill rolling condition setting device according to any one of claims 6 to 8.

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. JP 2021030280 A discloses a cold-rolling method for cold-rolling a rolling-object metal plate into a target shape. The cold-rolling method obtains a shape prediction model that predicts a shape upon input of at least: image information having a plurality of factors contributing to the shape of the metal plate after rolling; rolling condition results including and text information indicating a rolling operation state; and post-rolling shape results of the metal plate corresponding to the rolling condition results. The cold-rolling method predicts the shape of the rolling-object metal plate after rolling by inputting rolling conditions that are set into the shape prediction model. The cold-rolling method changes, on the basis of the predicted shape, the rolling conditions to be set. 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 co