JP5463743B2 - Slab hot rolling schedule determination method and slab hot rolling schedule determination device - Google Patents

Description

  The present invention relates to a technique for determining each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of a slab that is hot-rolled by a hot rolling facility.

  The hot rolling equipment for hot rolling a slab that is a thick plate material is generally rolled by a heating furnace that heats the slab, a reverse rolling mill that rolls the slab heated in the heating furnace, and a reverse rolling mill. A straightening machine that straightens the slab, a cooling bed that cools the slab straightened by the straightening machine, and a shearing machine that shears the slab cooled by the cooling bed into a plurality of rolled plates, and reverse A cooling facility is installed between the rolling mill and the straightening machine to adjust the slab temperature between rolling and rolling when the slab is reverse-rolled multiple times (repeated rolling) by the reverse-type rolling mill. Has been.

  When a plurality of types of rolled products are obtained by charging a plurality of slabs with different thicknesses or lengths into a heating furnace of such a hot rolling facility, the slabs charged in the heating furnace are extracted from the heating furnace. It is necessary to decide the order and time for each slab. However, since the order and time of extracting slabs from the heating furnace are conventionally determined by the operator's judgment, the slabs are extracted from the heating furnace when the number of slabs charged in the heating furnace reaches a large number. There is a problem that it takes a lot of time to determine the order and time. Therefore, based on the pass schedule information of each slab to be rolled, the slab extraction order determination problem is formulated as a mixed integer programming problem that minimizes the rolling completion time of all slabs while satisfying the rolling constraint conditions. There has been proposed a method for determining the order in which slabs are extracted from a heating furnace by obtaining a solution to the determined slab extraction order determination problem by a computer (see Patent Document 1).

JP 2003-305508 A

  According to the method disclosed in Patent Document 1, since the order in which slabs are extracted from the heating furnace is determined by the computer, the slabs are extracted from the heating furnace even when the number of slabs charged in the heating furnace reaches a large number. The order can be determined quickly. However, since the objective function of the optimization problem is to minimize the time to complete the rolling of all the slabs charged in the heating furnace, the shearing work of the slabs transported from the cooling bed to the shearing machine If time is required and the shear time of the slab greatly exceeds the rolling time, the slab carried from the reverse rolling mill to the cooling bed through the straightening machine will stay as a waiting slab to avoid this. There is a concern that the slab must be rolled at a reduced rolling speed.

  In addition, the method disclosed in Patent Document 1 is that the two slabs cannot be rolled simultaneously and overlapped, the temperature of the slab is controlled within a predetermined set time, the total length of the slabs during and during the rolling process Is the storage length in the waiting space and satisfying the constraints given by the preceding relationship between rolling are the constraints of the optimization problem, so additional slabs are required between the heating furnace and the reverse rolling mill. There is also a concern that it will not be possible if the equipment is installed.

Furthermore, since the extraction order decision problem including overtaking of slabs includes logical variable constraints, it is difficult to model in the framework of a mixed integer programming problem and obtain an executable solution at high speed.
The present invention has been made in view of the above-described problems, and heating, rolling, temperature control, correction, cooling, and shearing of the slab without inconvenience such as having to roll the slab at a reduced rolling speed. It is an object of the present invention to provide a slab hot rolling schedule determination method and a slab hot rolling schedule determination apparatus capable of quickly and optimally determining each process schedule.

  In order to solve the above-mentioned problems, the invention of claim 1 includes a heating furnace for heating a slab, a reverse rolling mill for rolling the slab heated in the heating furnace, and the heating furnace to the reverse rolling mill. A cooling device for adjusting the temperature of the supplied slab between rolling, a straightening machine that straightens the slab rolled by the reverse rolling mill, and a slab straightened by the straightening machine Identification information, dimensional information, and extraction of each slab that is hot-rolled in a hot rolling facility equipped with a cooling bed and a shearing machine that shears the slab cooled in the cooling bed and takes a plurality of rolled plates. Temperature information, material information, planing information, pass schedule information are stored in a database, and each process of heating, rolling, temperature control, straightening, cooling and shearing of the slab based on the information stored in the database Schedule In determining, the objective function is to minimize the time from the rolling start of the slab with the earliest extraction time to the shearing completion of the slab with the latest extraction time among the plurality of slabs charged in the heating furnace, and The solution of the optimization problem formulated as at least one of the constraint conditions that the number of slabs on the cooling bed when extracting the slab from the heating furnace does not exceed a predetermined slab number limit value is obtained by a computer. Each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of a slab is determined.

  The invention of claim 2 is the slab hot rolling schedule determination method according to claim 1, wherein the extraction time is the latest from the start of rolling of the slab with the earliest extraction time among the plurality of slabs charged in the heating furnace. The objective function is to minimize the time until slab shearing is completed, and the number of slabs on the cooling bed when the slab is extracted from the heating furnace does not exceed a predetermined limit on the number of slabs. The order of the processing schedule determined in the first step is not changed, two or more slabs are not simultaneously supplied to the reverse rolling mill, the cooling device, the straightening machine, the cooling bed and the shearing machine, Performing temperature control within a predetermined temperature control time limit, a slab waiting between the heating furnace and the reverse rolling mill, and a slab rolling with the reverse rolling mill The total length does not exceed a predetermined total limit length, and the total number of slabs waiting between the heating furnace and the reverse rolling mill and the slabs rolling in the reverse rolling mill is predetermined. The total limit is not exceeded, the temperature of the slab is controlled by either water cooling or air cooling, the slab is heated within a predetermined heating setting time, and the furnace is charged. Of the plurality of slabs, the slabs on the same conveyance path are extracted first from the side closer to the extraction end of the heating furnace, and the heating is performed except for the overtaking slabs of the plurality of slabs charged in the heating furnace. Slab rolling and temperature in the order extracted from the heating furnace, unless the overtaking equipment arranged between the furnace and the reverse rolling mill is not available, and the slab is not overtaken by the overtaking equipment. Adjustment, straightening, cooling, shearing Solution of the optimization problem formulated with the constraint that the starting time and each processing time of rolling, temperature control, straightening, cooling and shearing of the slab already extracted from the heating furnace are fixed values Is determined by a computer, and each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of the slab is determined.

  The invention of claim 3 is the method for determining the hot rolling schedule of slabs according to claim 1 or 2, wherein the number of slabs on the cooling floor when the slabs are extracted from the heating furnace is stored in the database as actual slab number information. In addition, a unit of carrying the difference between the number of slabs on the cooling bed when extracting the slab from the heating furnace and the actual number of slabs stored in the database to the cooling bed through the straightening machine from the reverse rolling mill Obtained as an estimation error between the number of slabs carried per hour and the number of slabs carried out per unit time to be carried out from the cooling bed to the shearing machine, It is prepared and each process schedule of heating, rolling, temperature control, cooling, and shearing of the slab is determined.

  Invention of Claim 4 rolls the temperature of the heating furnace which heats a slab, the reverse type rolling mill which rolls the slab heated by the heating furnace, and the slab supplied from the heating furnace to the reverse type rolling mill A cooling device for adjusting between the rolling and rolling, a straightening machine that straightens the slab rolled by the reverse rolling mill, a cooling bed that cools the slab straightened by the straightening machine, and the cooling bed Process schedules for heating, rolling, temperature control, shearing, cooling, and shearing of slabs that are hot-rolled in a hot-rolling facility equipped with a shearing machine that shears the cooled slab to plate a plurality of rolled plates A slab identification information, dimensional information, extraction temperature information, material information, planing information, and pass schedule information, and based on the information stored in the database. A schedule determining means for determining each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing, wherein the schedule determining means has the most extraction time among a plurality of slabs charged in the heating furnace. Formulating an optimization problem with the objective function of minimizing the time from the beginning of rolling of the early slab to the completion of shearing of the latest slab, and the number of slabs on the cooling bed when extracting the slab from the furnace Solves the optimization problem in the framework of constraint programming in which at least one of the constraint conditions is that the predetermined number of slabs does not exceed the predetermined slab number limit value, and the heating, rolling, temperature adjustment, correction, cooling, and shearing of the slab Each process schedule is determined.

  The invention of claim 5 is the slab hot rolling schedule determination apparatus according to claim 4, wherein the schedule determination means starts rolling the slab with the earliest extraction time among the plurality of slabs charged in the heating furnace. Formulation of an optimization problem whose objective function is to minimize the time from the slab with the latest extraction time to the completion of shearing, and the number of slabs on the cooling bed when extracting the slab from the heating furnace The number limit value is not exceeded, the order of the processing schedule initially determined for each slab is not changed, two or more slabs are the reverse rolling mill, the cooling device, the straightening machine, the cooling bed, and Not being supplied to the shearing machine at the same time, performing temperature control of the slab within a predetermined temperature control time limit, waiting between the heating furnace and the reverse rolling mill The total length of the lab and the slab being rolled by the reverse rolling mill does not exceed a predetermined total limit length, and the slab waiting between the heating furnace and the reverse rolling mill and the reverse rolling The total number of slabs being rolled by a machine does not exceed a predetermined total limit number, the temperature control of the slab is performed by either water cooling or air cooling, and the heating of the slab is a predetermined heating setting Of the plurality of slabs charged in the heating furnace, the slabs on the same conveyance path are extracted first from the side closer to the extraction end of the heating furnace, and charged in the heating furnace. Other than the slabs that can be overtaken among a plurality of slabs, the overtaking equipment arranged between the heating furnace and the reverse rolling mill cannot be used, as long as the overtaking equipment does not overtake the slabs Extracted from the furnace In the beginning, rolling, temperature control, straightening, cooling, and shearing of the slab are performed, and each start processing time and processing time of rolling, temperature control, straightening, cooling, and shearing of the slab already extracted from the heating furnace are fixed. It is characterized in that the optimization problem is solved in the framework of a constraint programming in which a value is a constraint condition, and each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of the slab is determined. It is.

The invention of claim 6 is the slab hot rolling schedule determination device according to claim 4 or 5, wherein the number of slabs on the cooling bed when the slab is extracted from the heating furnace is stored in the database as actual slab number information. The schedule deciding means calculates the difference between the number of slabs on the cooling bed when extracting the slab from the heating furnace and the actual number of slabs stored in the database from the reverse rolling mill to the cooling bed through a straightening machine. Obtained as an estimation error between the number of slabs carried in per unit time and the number of slabs carried out per unit time carried out from the cooling bed to the shearing machine, and an exponential smoothing value of the estimation error is added to the slab number limit value A constraint equation is created to determine each process schedule of heating, rolling, temperature control, cooling, and shearing of the slab.

  According to the first, second, fourth, and fifth aspects of the present invention, even when the shear time of the slab greatly exceeds the rolling time, the slab carried into the cooling bed from the reverse rolling mill through the straightening machine stays as a shear waiting slab. There is no. Therefore, it is possible to quickly and optimally determine the process schedules for heating, rolling, temperature control, straightening, cooling, and shearing of the slab without causing inconvenience such as rolling the slab at a reduced rolling speed.

In addition, optimization with logical constraints is optimized by a constraint programming framework that can obtain a feasible solution at high speed, so that operations including overtaking rolling can also be handled.
According to the third and sixth aspects of the invention, the exponential smoothing value is a correction coefficient for the slab number limit value, and the number of slabs carried per unit time that is carried from the reverse rolling mill to the cooling bed through the straightening machine and shearing from the cooling bed. Since the number of slabs on the cooling bed when extracting slabs from the heating furnace does not exceed the limit number of slabs, even if there is a large difference between the number of slabs delivered per unit time that is carried out to the machine, Each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of the slab can be determined more optimally.

It is a figure which shows an example of the hot rolling equipment with which one Embodiment of this invention is applied. It is a figure which shows an example of the schedule determination apparatus used when determining each process schedule of heating of a slab, rolling, temperature control, correction | amendment, cooling, and shearing by one Embodiment of this invention. It is a figure which shows an example of the information stored in a database. It is a flowchart for demonstrating the hot rolling schedule determination method of the slab which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the hot rolling schedule determination method of the slab which concerns on one Embodiment of this invention. It is a figure which shows an example of the result of having determined the hot rolling schedule of slab by one Embodiment of this invention. It is a figure which compares and shows the case where the hot rolling schedule of a slab is determined based on an operator's experience and intuition, and the case where it determines by one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
An example of hot rolling equipment to which an embodiment of the present invention is applied is shown in FIG. The hot rolling facility shown in FIG. 1 includes heating furnaces 2 and 4, reverse type rolling mill 6, straightening machine 8, cooling bed 10, shearing machine 12, cooling equipment 14, and overtaking equipment 16. , 4 are loaded with a plurality of slabs S in parallel by a slab loading table (not shown).

  While the plurality of slabs S charged in the heating furnaces 2 and 4 are transported to the extraction end of each heating furnace by a plurality of rows of slab transport roller tables (not shown) arranged in the heating furnaces 2 and 4. The slabs S heated and heated to a predetermined temperature (for example, 1200 ° C.) in the heating furnaces 2 and 4 are supplied to the reverse rolling mill 6 one by one, and are reverse-rolled (repeatedly) until a predetermined plate thickness is obtained. Rolled). Then, the slab S rolled by the reverse type rolling mill 6 is corrected for warpage or the like by the straightening machine 8, and then supplied to the shearing machine 12 through the cooling bed 10 for cooling the slab S. Here, the slab S has a predetermined plate width. It is sheared and rolled up into a plurality of rolled plates.

The cooling facility 14 is for adjusting the temperature of the slab S between rolling and is arranged between the reverse rolling mill 6 and the straightening machine 8.
The overtaking equipment 16 has a temperature control time of a slab extracted first from the heating furnace 2 or the heating furnace 4 (hereinafter referred to as “preceding slab”), and a slab (hereinafter referred to as “rear”) extracted from the heating furnace 2 or the heating furnace 4 later. This is for reversing the relationship between the preceding slab and the succeeding slab when it is longer than the temperature control time of “line slab”), and is arranged between the heating furnaces 2 and 4 and the reverse rolling mill 6. ing.

Note that the slab S sheared into a plurality of rolled plates by the shearing machine 12 is maintained by a maintenance equipment 18 disposed downstream of the straightening machine 8.
FIG. 2 shows an example of a schedule determination device used for determining each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of a slab according to an embodiment of the present invention, and FIG. An example of the stored information is shown in FIG.

  The schedule determination device shown in FIG. 2 includes a database 20, an information collection device 22, an execution control device 24, a computer (schedule determination means) 30, and the like. The database 20 includes information shown in FIG. Identification information (slab No.), dimension information (thickness, length, width, etc.), extraction temperature information (extraction upper limit temperature, extraction lower limit temperature, etc.), material information (steel grade, etc.) ), Plate cutting information (shear width, number of plate cutting, etc.), pass schedule information (number of rolling, rolling time, rolling dimension, rolling temperature, temperature control temperature, temperature control timing, temperature control method, etc.) are stored.

  The database 20 includes various information collected from the hot rolling equipment by the information collecting device 22 (the current state of the slab extracted from the heating furnace, the number of slabs on the cooling bed when extracting the slab from the heating furnace, The number of slabs on the cooling floor when the slab is extracted from the heating furnace, the actual start time and the actual processing time when the slab is actually processed in each process, and the like are stored. Of the various information collected, the number of slabs on the cooling floor when slabs are extracted from the heating furnace is stored in the database 20 as actual slab number information.

The execution control device 24 displays the information stored in the database 20 on a display device 26 such as a monitor television, or corrects the content of the information stored in the database 20. A command for correcting the contents of the command is input to the execution control device 24 from an input device 28 such as a keyboard.
Based on the information stored in the database 20, the computer 30 schedules each process of heating, rolling, temperature control, correction, cooling, and shearing of the slab (heating start time, heating process time, extraction temperature, rolling start time, rolling process Time, temperature control start time, correction start time, correction processing time, cooling start time, cooling processing time, shearing start time, shearing processing time, shearing end time, etc.), which are determined by this computer 30. The process schedule is supplied as a process control signal to each device of the hot rolling facility from the process control device 32 via the shared communication path 34.

  The computer 30 also has a CPU (Central Processing Unit) 301, a RAM (Random Access Memory) 302, and a ROM (Read Only Memory) 303. The ROM 303 has a cooling bed on which a slab is extracted from a heating furnace. Slab number limit value that limits the number of slabs in the slab, temperature control time limit that limits the slab temperature adjustment processing time, slabs that are waiting between the heating furnace and the reverse type rolling mill and slabs that are being rolled by the reverse type rolling mill The total limit length for limiting the total length and the heating setting time for limiting the heating time of the slab are stored as constraint condition information.

4 and 5 are diagrams for explaining a method for determining a hot rolling schedule for a slab according to an embodiment of the present invention. The CPU 301 of the computer 30 shown in FIG. Each process schedule of heating, rolling, temperature control, straightening, cooling, and shearing is determined.
That is, the CPU 301 determines whether or not there are a plurality of slabs S in the heating furnace 2 or the heating furnace 4 based on the current state information stored in the database 20. When the slab S exists, the identification information, dimension information, extraction temperature information, material information, plate cutting information, and path scheduling information of each slab S existing in the heating furnace 2 or the heating furnace 4 are read from the database 20 ( (See steps S1 and S2 in FIG. 4).

If necessary information is acquired from the database 20 in step S2 of FIG. 4, the CPU 301 extracts the current number of slabs on the cooling bed when the slab S is extracted from the heating furnace 2 or the heating furnace 4 and the heating furnace 2 or the heating furnace 4. The number of past slabs on the cooling floor when the slab S is extracted from the database (actual slab number information) is acquired from the database 20, and the difference between the current number of slabs on the cooling floor and the number of past slabs is obtained by the reverse rolling mill 6 The following equation (1) is used as an estimation error α between the number of slabs carried per unit time that is carried into the cooling bed 10 through the straightening machine 8 and the number of slabs carried out per unit time that is carried out from the cooling bed 10 to the shearing machine 12. (See step S3 in FIG. 4). When the estimated error α is obtained from the equation (1), the CPU 301 obtains an exponential smoothed value α ^* obtained by exponentially smoothing the estimated error α from the following equation (2) (see step S4 in FIG. 4).

If the exponential smoothing value α ^* of the estimation error α is obtained from the equation (2) in step S4 of FIG. 4, the CPU 301 shows the exponential smoothing value α ^* as the correction coefficient for the slab number limit value in the following equation (3). A constraint equation is created, and the created constraint equation is stored in the RAM 302 (see step S5 in FIG. 4).

   If the constraint equation shown in equation (3) is created in step S5 of FIG. 4, the CPU 301 loads from the extraction end of the heating furnaces 2 and 4 out of all the slabs S present in the heating furnaces 2 and 4. The process schedules of heating, rolling, temperature control, correction, cooling, and shearing of each slab up to the X (X ≧ 1) row are determined based on the information acquired in step S2.

  Specifically, as shown in FIG. 5, for example, when the number of slabs from the extraction ends of the heating furnaces 2 and 4 to the third row is 12 in the 12th slab S, The optimization problem with the objective function of minimizing the time from the start of rolling of the slab with the earliest extraction time to the completion of shearing with the slab with the latest extraction time is formulated. The solution is solved in the framework of constraint programming with ˜12 as constraint conditions (see steps S6 and S7 in FIG. 4). Then, based on the solution of the optimization problem obtained in step S7, each process schedule of heating, rolling, temperature control, correction, cooling, and shearing of 12 slabs S is determined, and the determined schedule items are stored in the database 20. Store (see steps S8 and S9 in FIG. 4). In addition, as constraint programming, the Journal of Artificial Intelligence, vol. 6, no. 6, p47-59, 1991 can be used.

[Restrictions]
Condition 1: The order of the processing schedule decided first for each slab must not be changed.
Condition 2: Two or more slabs are not supplied to the reverse rolling mill, the cooling device, the straightening machine, the cooling bed and the shearing machine at the same time.
Condition 3: Slab temperature adjustment is performed within a predetermined temperature adjustment time limit.
Condition 4: The total length of the slab waiting between the heating furnace and the reverse type rolling mill and the slab being rolled by the reverse type rolling mill does not exceed a predetermined total limit length.
Condition 5: The total number of slabs waiting between the heating furnace and the reverse rolling mill and the slabs rolling by the reverse rolling mill does not exceed a predetermined total limit.

Condition 6: The temperature of the slab is controlled by either water cooling or air cooling.
Condition 7: The slab is heated within a predetermined heating setting time.
Condition 8: Among a plurality of slabs charged in the heating furnace, slabs on the same conveyance path should be extracted first from the side closer to the extraction end of the heating furnace.
Condition 9: The overtaking equipment arranged between the heating furnace and the reverse rolling mill cannot be used except for the slab that can be overtaken among the plurality of slabs charged in the heating furnace.
Condition 10: Unless the slab is overtaken by the overtaking equipment, the slab is rolled, temperature-controlled, straightened, cooled, and sheared in the order extracted from the heating furnace.
Condition 11: The number of slabs on the cooling bed when the slab is extracted from the heating furnace does not exceed the slab number limit value (the number of slabs on the cooling bed when the slab is extracted from the heating furnace is the constraint equation of formula (3) Meet).
Condition 12: Rolling, temperature control, straightening, cooling, and shearing start times and processing times of slabs already extracted from the heating furnace shall be fixed values.

  The constraint conditions 1 to 8, 11, and 12 can be handled by an intuitive description method, but the constraint conditions 9 and 10 cannot be described intuitively because they include a logical constraint (if-then) for the decision variable. . A method of responding by checking the solution sequentially in the iterative calculation in the algorithm can be mentioned, but it is not realistic because there is a concern about deterioration of the solution due to an increase in calculation load. Therefore, the model for the constraint conditions 9 and 10 is a description in which assumed rolling candidate patterns are listed and one of the listed candidates is selected.

For example, when the processing in a rolling mill of a certain slab is “rolling process 1, cooling process 2, rolling process 3”, it is assumed that cooling process 2 can be replaced by overtaking. then,
(A) Rolling process 1, cooling process, rolling process 2
(B) Rolling process 1, overtaking cooling, rolling process 2
These patterns are enumerated, and this pattern is selected as a decision variable. By using this decision variable, the condition 10 is constrained.

FIG. 6 is a diagram showing an example of a result of determining a slab hot rolling schedule according to an embodiment of the present invention. In this figure, process schedules of four slabs extracted from a heating furnace are shown.
FIG. 7 is a diagram showing a comparison between the case where the hot rolling schedule of the slab is determined based on the experience and intuition of the operator (conventional) and the case where it is determined according to one embodiment of the present invention. As described above, the hot rolling schedule of the slab was determined based on the experience and intuition of the operator, and the time required to complete the shearing of the seven slabs extracted sequentially from the heating furnace was about 102 minutes. did.

  On the other hand, the hot rolling schedule of the slab was determined according to one embodiment of the present invention, and the time until the shearing of the seven slabs extracted sequentially from the heating furnace was measured is shown in FIG. As such, it ended in about 90 minutes. Therefore, by determining the hot rolling schedule of the slab with a computer, it is possible to determine the hot rolling schedule of the slab in a short time compared with the case where it is determined by the operator's judgment.

  As described above, the dimension information, extraction temperature information, material information, plate cutting information, and path scheduling information of each slab that is hot-rolled by the hot rolling equipment are stored in the database 20 and stored in the database 20. When slab heating, rolling, temperature control, straightening, cooling, and shearing process schedules are determined based on information, from the start of rolling the slab with the earliest extraction time among multiple slabs charged in the heating furnace Heating the slab by using the computer 30 to find a solution to the optimization problem formulated with the objective function to minimize the time until the shearing of the slab with the latest extraction time is completed and with the above conditions 1 to 12 as constraints When the rolling, temperature control, straightening, cooling, and shearing process schedules are determined, even if the slab shear time greatly exceeds the rolling time, the reverse rolling mill 6 Never slabs carried into the cooling bed 10 through Masaki 8 stays as shear waiting slabs. Therefore, it is possible to quickly and optimally determine the process schedules for heating, rolling, temperature control, straightening, cooling, and shearing of the slab without causing inconvenience such as rolling the slab at a reduced rolling speed.

In addition, as described above, the number of slabs on the cooling bed when the slab is extracted from the heating furnace is stored in the database 20 as actual slab number information, and the number of slabs on the cooling bed when the slab is extracted from the heating furnace The difference between the actual slab number information stored in the database 20 and the number of slabs per unit time that is transferred from the reverse rolling mill to the cooling floor through the straightening machine and the unit time that is transferred from the cooling floor to the shearing machine. Estimated error α with the number of slabs carried out, and create a constraint equation with exponential smoothing value α ^* of estimated error α added to the slab number limit value to schedule each process of heating, rolling, temperature control, cooling, and shearing of the slab Is determined, the exponential smoothing value α ^* becomes the correction coefficient for the slab number limit value, and the number of slabs carried per unit time and the cooling bed that are transferred from the reverse rolling mill to the cooling bed through the straightening machine The number of slabs on the cooling bed when extracting slabs from the heating furnace may exceed the limit number of slabs even when there is a difference in the size between the number of slabs delivered per unit time and the number of slabs delivered to the shearing machine. Therefore, the process schedules for heating, rolling, temperature control, straightening, cooling and shearing of the slab can be determined more optimally.

In the above-described embodiment of the present invention, the case where the number of heating furnaces is applied to a hot rolling facility having two heating furnaces is illustrated, but the number of heating furnaces may be one or three or more.
Moreover, although the case where it applied to the hot rolling facility by which the overtaking equipment was arrange | positioned between a heating furnace and a reverse type rolling mill was illustrated, it does not have an overtaking equipment between a heating furnace and a reverse type rolling mill The present invention can also be applied to hot rolling equipment.

  Further, in the example shown in FIG. 5, the schedule determination target slab is the slab up to the third row from the extraction end of the heating furnaces 2 and 4 toward the charging side, but is not limited to this. For example, the heating furnace The slab from the extraction end to the first or second row from the extraction end may be set as the schedule determination target slab.

  DESCRIPTION OF SYMBOLS 2,4 ... Heating furnace, 6 ... Reverse type rolling mill, 8 ... Straightening machine, 10 ... Cooling bed, 12 ... Shearing machine, 14 ... Cooling equipment, 16 ... Overtaking equipment, 18 ... Care equipment, 20 ... Database, 22 DESCRIPTION OF SYMBOLS ... Information collection device 24 ... Execution control device 26 ... Display device 28 ... Input device 30 ... Computer (schedule determining means) 301 ... CPU 302 ... RAM 303 ... ROM

Claims (6)

A heating furnace that heats the slab, a reverse rolling mill that rolls the slab heated in the heating furnace, and a temperature of the slab supplied from the heating furnace to the reverse rolling mill is adjusted between rolling and rolling. A cooling device for correcting the slab rolled by the reverse rolling mill, a cooling bed for cooling the slab straightened by the straightening machine, and shearing the slab cooled by the cooling bed. A database of identification information, dimension information, extraction temperature information, material information, plate cutting information, and pass schedule information for each slab that is hot rolled in a hot rolling facility equipped with a shearing machine that strips a plurality of rolled plates In determining the process schedule of heating, rolling, temperature control, straightening, cooling, and shearing of the slab based on the information stored in the database,
The objective function is to minimize the time from the rolling start of the slab with the earliest extraction time to the shearing completion of the slab with the latest extraction time among the plurality of slabs charged in the heating furnace, and from the heating furnace Heating the slab by obtaining a solution of an optimization problem formulated as at least one of the constraint conditions that the number of slabs on the cooling floor when extracting the slab does not exceed a predetermined slab number limit value, A method for determining a hot rolling schedule for a slab, comprising determining each process schedule of rolling, temperature control, straightening, cooling, and shearing.   The objective function is to minimize the time from the rolling start of the slab with the earliest extraction time to the shearing completion of the slab with the latest extraction time among the plurality of slabs charged in the heating furnace, and from the heating furnace The number of slabs on the cooling floor when extracting slabs does not exceed a predetermined limit on the number of slabs, the order of the processing schedule initially determined for each slab is not changed, and two or more slabs are reverse A simultaneous rolling mill, the cooling device, the straightening machine, the cooling bed and the shearing machine, the temperature adjustment of the slab within a predetermined temperature control time limit, the heating furnace and the reverse type The total length of the slab waiting between the rolling mill and the slab being rolled by the reverse rolling mill does not exceed a predetermined total limit length, the heating furnace and the reverse rolling mill The total number of slabs waiting in between and the slabs being rolled by the reverse rolling mill does not exceed a predetermined total limit number, and the temperature of the slab is controlled by either water cooling or air cooling That the heating of the slab is performed within a predetermined heating setting time, and the slabs on the same conveyance path among the plurality of slabs charged in the heating furnace are extracted first from the one near the extraction end of the heating furnace. The overheating equipment disposed between the heating furnace and the reverse rolling mill can be used only for the overtaking slabs out of the plurality of slabs charged in the heating furnace, Rolling of slabs, temperature control, correction, cooling, and shearing are performed in the order extracted from the heating furnace, unless the slabs are overtaken by the overhead equipment, rolling of the slabs already extracted from the heating furnace, Temperature control, straightening, cooling, shearing Each process schedule of heating, rolling, temperature control, correction, cooling, and shearing of the slab is determined by a computer by finding a solution to the optimization problem formulated with the start processing time and each processing time as fixed values. The slab hot rolling schedule determination method according to claim 1, wherein the slab hot rolling schedule is determined.   It is a hot rolling schedule determination method of the slab of Claim 1 or 2, Comprising: The slab number on the cooling floor when extracting the slab from the said heating furnace is stored in the said database as performance slab number information, The said heating The difference between the number of slabs on the cooling floor when extracting the slab from the furnace and the actual number of slabs stored in the database is transferred from the reverse rolling mill to the cooling floor through the straightening machine, and the slab is loaded per unit time. And calculating a constraint equation in which an exponential smooth value of the estimation error is added to the slab number limit value to obtain an estimation error between the number of slabs discharged from the cooling bed to the shearing machine per unit time. A method for determining a hot rolling schedule of a slab, comprising determining each process schedule of heating, rolling, temperature control, cooling, and shearing. A heating furnace for heating the slab, a reverse rolling mill for rolling the slab heated in the heating furnace, a cooling device for adjusting the temperature of the slab supplied from the heating furnace to the reverse rolling mill, A straightening machine that straightens the slab rolled by the reverse rolling mill, a cooling bed that cools the slab straightened by the straightening machine, and a slab that is cooled by the cooling bed is sheared to form a plurality of rolled plates. An apparatus for determining each process schedule of heating, rolling, temperature control, shearing, cooling, and shearing of a slab that is hot-rolled in a hot-rolling facility equipped with a shearing machine,
A database for storing identification information of the slab, dimension information, extraction temperature information, material information, planing information, and pass schedule information;
Schedule determination means for determining each process schedule of heating, rolling, temperature control, correction, cooling, and shearing of the slab based on the information stored in the database;
The schedule determining means minimizes the time from the start of rolling of the slab with the earliest extraction time to the shearing completion of the slab with the latest extraction time among the plurality of slabs charged into the furnace. In the constraint programming framework, the optimization problem is formulated, and the number of slabs on the cooling bed when the slab is extracted from the heating furnace does not exceed a predetermined slab number limit value. An apparatus for determining a hot rolling schedule of a slab, which solves an optimization problem and determines each process schedule of heating, rolling, temperature control, straightening, cooling and shearing of the slab.   5. The slab hot rolling schedule determination device according to claim 4, wherein the schedule determination means includes a slab having a latest extraction time from a rolling start of a slab having the earliest extraction time among a plurality of slabs charged in the heating furnace. Formulate an optimization problem with the objective function of minimizing the time until the completion of shearing, and the number of slabs on the cooling bed when extracting slabs from the heating furnace does not exceed a predetermined slab number limit The order of the processing schedule initially determined for each slab is not changed, and two or more slabs are not supplied simultaneously to the reverse rolling mill, the cooling device, the straightening machine, the cooling bed and the shearing machine. The temperature adjustment of the slab within a predetermined temperature control time limit, and the slab and the river on standby between the heating furnace and the reverse rolling mill The total length of the slab being rolled by the rolling mill does not exceed a predetermined total limit length, the slab waiting between the heating furnace and the reverse rolling mill, and being rolled by the reverse rolling mill The total number of the slabs does not exceed a predetermined total limit number, the temperature of the slab is controlled by either water cooling or air cooling, and the heating of the slab is performed within a predetermined heating setting time. Among the plurality of slabs charged in the heating furnace, the slabs on the same conveyance path are extracted first from the side closer to the extraction end of the heating furnace, the plurality of slabs charged in the heating furnace Of the slabs other than the slab that can be overtaken, the overtaking equipment arranged between the heating furnace and the reverse rolling mill cannot be used, unless the slab is overtaken by the overtaking equipment. Rolling slabs in the extracted order Restriction that temperature control, correction, cooling, and shearing are performed, and that the start processing time and processing time of rolling, temperature control, correction, cooling, and shearing of slabs already extracted from the heating furnace are fixed values. Determination of a hot rolling schedule for a slab characterized by solving the optimization problem in a constraint programming framework as a condition and determining each process schedule of heating, rolling, temperature control, correction, cooling, and shearing of the slab apparatus. The slab hot rolling schedule determination device according to claim 4 or 5, wherein the number of slabs on the cooling floor when the slab is extracted from the heating furnace is stored as actual slab number information in the database, and the schedule determination means The difference between the number of slabs on the cooling floor when extracting the slab from the heating furnace and the actual slab number information stored in the database per unit time carried into the cooling bed from the reverse rolling mill through the straightening machine Obtained as an estimation error between the number of slabs carried in and the number of slabs carried out per unit time carried out from the cooling bed to the shearing machine, and created a constraint equation in which the exponential smoothing value of the estimation error was added to the slab number limit value A slab hot rolling schedule determination device characterized by determining each process schedule of heating, rolling, temperature control, cooling, and shearing of the slab .

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