JP2019022900A - Method for manufacturing thick steel plate - Google Patents

Abstract

To provide a method for manufacturing a thick steel plate by which both of assurance of a target temperature and improvement of a rolling efficiency can be achieved in the case that when manufacturing a thick steel plate, a passage cooling type cooling appliance is installed in close proximity to a reversible type rolling machine, a rolling/cooling path for cooling by the passage cooling type cooling appliance while rolling by the reversible rolling machine is assembled to a pass schedule (for example, in the case that a thick steel plate is manufactured by controlled rolling).SOLUTION: A method for manufacturing a thick steel plate is characterized in that an upper limit of a pass number of a rolling/cooling path is determined, cooling calculation is performed for all rolling/cooling patterns, a rolling/cooling pattern, in which a predetermined temperature is obtained when a rolled material becomes a predetermined plate thickness, is extracted from the rolling/cooling patterns for which cooling calculation has been performed, and a rolling/cooling pattern, in which a rolling time becomes minimum, is adopted from the extracted rolling/cooling patterns.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a thick steel plate.

  When producing a thick steel plate by controlled rolling, etc., until the rolled material reaches a predetermined plate thickness (for example, control rolling start plate thickness), until a predetermined target temperature (for example, controlled rolling start temperature) is reached. In order to shorten the waiting time for cooling, a cooling system (water cooling system) is installed close to the reversible rolling mill, and the pass schedule is cooled by the cooling system while passing through the reversible rolling mill. A method of incorporating a rolling / cooling pass is performed (for example, Patent Documents 1 to 3).

Japanese Patent Laying-Open No. 2015-91604 JP 2011-147862 A JP 2011-143462 A

  However, in the above-mentioned patent documents 1 to 3, rolling in which a predetermined target temperature (for example, controlled rolling start temperature) is obtained when the rolled material reaches a predetermined sheet thickness (for example, controlled rolling start sheet thickness).・ The main focus is on determining the cooling pattern (the number of rolling / cooling passes, the presence or absence of rolling with a reversible rolling mill in each rolling / cooling pass), and the rolling efficiency is not considered much. There was a problem.

  The present invention has been made in view of the circumstances as described above, and when producing a thick steel plate, a refrigerating rolling mill is installed in the vicinity of the reversible rolling mill and a reversible rolling mill is used in a pass schedule. In the case of incorporating a rolling / cooling pass that is cooled by a passing cooling type cooling facility while rolling at (for example, manufacturing a thick steel plate by controlled rolling), it is possible to achieve both ensuring of the target temperature and improvement of rolling efficiency. It aims at providing the manufacturing method of a thick steel plate.

  In order to solve the above problems, the present invention has the following features.

  [1] When manufacturing thick steel plates, rolling / cooling is performed by placing a passing cooling type cooling facility in the vicinity of the reversible rolling mill and cooling with a passing cooling type cooling facility while rolling with the reversible rolling mill in the pass schedule. In the case of incorporating a pass, an upper limit of the number of passes of the rolling / cooling pass is determined, cooling calculation is performed for all rolling / cooling patterns, and a rolling material is determined in advance from the rolling / cooling patterns subjected to the cooling calculation. A rolling / cooling pattern that obtains a predetermined target temperature when the plate thickness is reached is extracted, and a rolling / cooling pattern that minimizes the rolling time is adopted among the extracted rolling / cooling patterns. Manufacturing method of thick steel plate.

  [2] The method for producing a thick steel plate according to [1], wherein the thick steel plate is produced by controlled rolling.

  In the present invention, when manufacturing a thick steel plate, a rolling cooling system is installed in the vicinity of the reversible rolling mill, and the pass schedule is rolled by the cooling cooling system while being rolled by the reversible rolling mill. -When incorporating a cooling path (for example, when manufacturing a thick steel plate by controlled rolling), it is possible to achieve both ensuring of the target temperature and improvement of rolling efficiency.

It is a figure which shows the rolling process based on one Embodiment of this invention. It is a figure which shows the conventional rolling and cooling pattern determination logic. It is a figure which shows the rolling and cooling pattern determination logic in one Embodiment of this invention. In the Example of this invention, it is the figure which compared the pass schedule (delivery side thickness, temperature). In the Example of this invention, it is the figure which compared the rolling time.

  The manufacturing method of the thick steel plate in one Embodiment of this invention is demonstrated based on drawing. Here, a case where a thick steel plate is manufactured by controlled rolling will be described in mind.

  FIG. 1 is a diagram illustrating a rolling process based on an embodiment of the present invention.

  As shown in FIG. 1, in this rolling process, a heating furnace 1, a rolling mill (reversible rolling mill) 2, and a cooling facility (pass cooling type cooling facility) arranged close to the downstream side of the rolling mill 2. 3 is provided.

  In addition, this through-cooling type cooling facility 3 has a constant flow rate of the cooling water and controls the supply / stop (ON / OFF) of the cooling water. Moreover, the conveyance speed of the rolling material 10 can be adjusted in a predetermined range.

  And it rolls with respect to the rolling material (thick steel plate) 10 extracted from the heating furnace 1 by the following pass schedules.

  First, between the points A and B is a pass (normal pass) in which normal rolling is performed by the reversible rolling mill 2.

  Next, between point B and point C is a pass (rolling / cooling pass) that is cooled by the passing cooling type cooling facility 3 while being rolled by the reversible rolling mill 2. At that time, at point C, when the rolled material 10 reaches a predetermined plate thickness (here, controlled rolling start plate thickness), a predetermined target temperature (here, controlled rolling start temperature) is set. To do. For the target temperature, an allowable range (for example, target temperature ± 3 ° C.) is provided.

  Finally, between point C and point D is a pass (normal pass: controlled rolling pass) in which the reversible rolling machine 2 performs normal rolling from the control rolling start plate thickness to the finishing plate thickness.

  Then, when a rolling / cooling pass that is cooled by the passing cooling type cooling equipment 3 while being rolled by the reversible rolling mill 2 is incorporated in the pass schedule as described above (here, when a thick steel plate is manufactured by controlled rolling) FIG. 2 shows a conventional procedure (determination logic) for determining a rolling / cooling pattern (number of rolling / cooling passes, presence / absence of rolling in the reversible rolling mill 2 in each rolling / cooling pass). FIG. 3 shows a procedure (decision logic) in one embodiment of the present invention.

  First, as shown in FIG. 2, conventionally, rolling and cooling patterns are arranged in order, calculation is started from the first rolling and cooling pattern, and control rolling is performed when the rolled material 10 reaches the control rolling start plate thickness. The calculation is terminated when a rolling / cooling pattern (rolling / cooling pattern with good cooling) at which a start temperature of ± 3 ° C. is obtained is obtained. A rolling / cooling pattern with good cooling was adopted.

  Therefore, conventionally, the employed rolling / cooling pattern is not necessarily the rolling / cooling pattern in which the rolling time is minimized.

  On the other hand, in one embodiment of the present invention, the rolling / cooling pattern is determined as shown in FIG.

  (S1) Cooling calculation is performed for all rolling / cooling patterns. Since the rolling time tends to be long if the number of rolling / cooling passes is large, an upper limit (for example, 8 passes) is provided for the number of rolling / cooling passes.

  (S2) Of all the rolling / cooling patterns subjected to the cooling calculation in (S1) above, the temperature of the controlled rolling start temperature ± 3 ° C. is obtained when the rolled material 10 reaches the controlled rolling start plate thickness. Extract rolling / cooling pattern (rolling / cooling pattern with good cooling).

  (S3) Next, each rolling time is calculated about the rolling-cooling pattern with favorable cooling extracted by said (S2).

  (S4) Then, based on the calculation result in (S3) above, a rolling / cooling pattern that minimizes the rolling time is adopted.

  Thus, in this embodiment, when manufacturing a thick steel plate, a cooling system for passing cooling is installed in the vicinity of the reversible rolling mill, and the passing cooling method is performed while rolling with the reversible rolling mill in the pass schedule. In the case of incorporating a rolling / cooling pass for cooling with a cooling facility (for example, when producing a thick steel plate by controlled rolling), it is possible to achieve both ensuring of the target temperature and improvement of rolling efficiency.

  As an example of the present invention, when a rolling / cooling pattern is determined by the conventional determination logic shown in FIG. 2 (conventional example) for the thick steel plate having the same dimensions and the same controlled rolling condition, the present invention shown in FIG. The case where the rolling / cooling pattern was determined by the determination logic in the embodiment of the invention (example of the present invention) was compared.

  FIG. 4 shows a comparison of pass schedules (outside thickness and temperature) between the conventional example and the present invention, and FIG. 5 shows a comparison of rolling times between the conventional example and the present invention.

  As shown in FIG. 4, the rolling / cooling pass is 6 passes in the conventional example, whereas the rolling / cooling pass is 4 passes in the example of the present invention.

  As shown in FIG. 5, the rolling time is 203 sec in the conventional example, while the rolling time is 190 sec and 13 sec shorter in the example of the present invention.

  This confirmed the effectiveness of the present invention.

1 Heating furnace 2 Rolling mill (reversible rolling mill)
3 Cooling equipment (pass cooling type cooling equipment)
10 Rolled material (thick steel plate)

Claims (2)

  When manufacturing thick steel plates, a cooling system is installed near the reversible rolling mill, and a rolling / cooling path that cools with the cooling system while passing through the reversible rolling mill is incorporated in the pass schedule. In this case, the upper limit of the number of passes of the rolling / cooling pass is set, the cooling calculation is performed for all the rolling / cooling patterns, and the rolling material is set to a predetermined thickness from the rolling / cooling patterns subjected to the cooling calculation. A rolling / cooling pattern that obtains a predetermined target temperature is extracted when it becomes, and among the extracted rolling / cooling patterns, a rolling / cooling pattern that minimizes rolling time is adopted. Production method.   It is a case where a thick steel plate is manufactured by controlled rolling, The manufacturing method of the thick steel plate of Claim 1 characterized by the above-mentioned.

Images