JP2008080395A - Heating furnace charging order determining method and apparatus for the determination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating furnace charging order determining method, which can reduce a wasteful residence time in a heating furnace and further can enhance the efficiency of rolling, when heating a plurality of types of slabs, while satisfying the requirement of a slab in-furnace time. <P>SOLUTION: This heating furnace charging order determining method comprises a step S1 of reading attribute data and rolling restriction data for object rolling slabs, grouping the slabs based on the attribute data, preparing small rolling groups based on the attribute data and the rolling restriction data, preparing rolling order data while taking into consideration the rolling restriction data, and preparing the order of charging of the slabs into the heating furnace, and a step S2 of successively carrying out slab transfer or replacement based on the rolling order data prepared by step S1, preparing the rolling order and heating furnace charging order, calculating a contemplated function, and repeating the improvement of the numerical values to determine a rolling order, which can realize a shorter total rolling time, and a heating furnace charging order which can realize a shorter waiting period for heating furnace extraction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heating furnace charging order determination method and a determination apparatus thereof for enabling high efficiency in rolling when rolling a plurality of types of slabs, particularly in a plurality of types of raw materials.

  In the hot rolling process for thick plates, the rolled material manufactured in the steel making process (hereinafter referred to as “slab”) is heated in a heating furnace and rolled in a rolling mill, so that a plurality of types can be obtained. Thick rolled products are produced. When manufacturing multiple types of rolled products, the order of charging each slab into the furnace and the planning of the rolling order of the heated slab rolling mill are important because they greatly affect production efficiency and production cost. Become. Here, with respect to heating and rolling, since there are many constraints depending on the material, width, thickness, etc. of each slab, the planning is extremely complicated.

  Generally, a rolling mill in a thick plate factory is configured such that a roll can be rotated forward and reversely, and a slab conveyed to the rolling mill is passed through a roll a plurality of times so as to be rolled. Reverse rolling is performed. By this reverse rolling, the material is built to a predetermined size. In addition, there are standby spaces on the front surface (upstream) and rear surface (downstream) of the rolling mill where a slab can be made to stand by, so that one slab during rolling is made to wait in the standby space and the next slab is rolled. The machine can be rolled. The slab rolled by the rolling mill in this way is cooled as necessary by a water cooling device located upstream and downstream of the rolling mill. In addition, there may be a facility that lifts the rolling line to a height that allows other slabs to pass and keeps it in a standby state, so-called passing rolling equipment. On the other hand, other slabs can be passed over and rolled during cooling.

  In such a thick plate factory, a slab is reverse-rolled by a rolling mill to produce a product having a predetermined size. In this way, various products are produced, but the number of passes in the rolling mill and the rolling time are different for each slab. Here, the rolling process can be divided into two processes, ie, a forming / bending process and a thicknessing process. Some slabs do not require a molding / de-widthing process.

  In addition, in the thickening process, temperature adjustment may be performed in order to build the product material. In this temperature adjustment, rolling is performed after the slab waits on the front and rear surfaces of the rolling mill or overtaking rolling equipment in the vicinity of the final pass, and is brought into a predetermined temperature range, and is also referred to as controlled rolling. Further, the temperature adjustment may be performed a plurality of times, and the number of temperature adjustments varies depending on the slab. The number of temperature adjustments is, for example, 0 to 4 times. The temperature adjustment may be performed by air cooling or by using a water cooling device.

  Processes such as rolling and temperature adjustment as described above are combined in accordance with the slab, and the material is created as a predetermined product. This is called a rolling schedule or a pass schedule. And since contents, such as rolling and temperature control, differ with slabs, a pass schedule also changes with kinds of slabs.

  In order to maximize the rolling efficiency, it is necessary to minimize the idle time of the rolling mill by making good use of the standby space on the front and rear of the rolling mill and the overtaking rolling equipment according to the slab pass schedule. It is done.

  On the other hand, the slab to be rolled is heated in a heating furnace before rolling. There are a plurality of types of slabs, and in order to heat to the target temperature at the time of extraction from the heating furnace, the time required for heating in the heating furnace (hereinafter referred to as “in-furnace time”) is determined. Since the slab cannot be extracted from the heating furnace until the residence time in the heating furnace satisfies the in-furnace time, idle time of the rolling mill is generated. In addition, if the slab stays in the heating furnace longer than the in-furnace time, energy is lost in the heating furnace.

  Thus, in order to perform an efficient operation in a thick plate factory, optimization from the viewpoints of both rolling in a rolling mill and heating in a heating furnace is required.

  Conventionally, various methods are known as a scheduling method considering a rolling mill and a heating furnace.

  For example, Patent Document 1 describes the following method. First, in heating group forming step 18, heating groups (a) to (e) that can be charged in the same heating furnace are formed, and based on this heating group, in rolling group forming step 20, simultaneously supplied to the rolling mill. Form possible rolling groups. Then, the rolling order and the heating furnace are assigned in units of this rolling group. According to the method of Patent Document 1, since the rolling order and the allocation of the heating furnace are selected based on the grouping in consideration of the heating conditions, for example, the same heating condition is set in the same heating furnace due to quality problems or the like. Even when it is required to charge and heat only the slab, the slab is charged into the heating furnace so that excellent rolling efficiency can be obtained while preferentially satisfying such heating conditions. The order and the rolling order by the rolling mill can be determined optimally.

  Patent Document 2 describes the following method. First, all the slabs to be scheduled are grouped, and the synchronization rule that gives a higher evaluation score as the difference between the heating speed and the rolling speed is smaller, and the higher the evaluation score is given as the difference in heating conditions between the front and rear groups is smaller The primary plan of the arrangement order of all groups is determined according to the context rule. Next, an evaluation of heating loss time and rolling loss time and an evaluation of total power cost are performed based on this primary plan, and the total power cost is minimized so long as the increase in rolling loss time does not exceed the allowable range. Calculate the order again to determine the order of all groups.

Patent Document 3 describes the following method. First, in steps S1 to S3, information including the occupation time of the rolling mill when rolling is obtained based on the pass schedule of each material to be rolled. Next, in step S4, based on the obtained information, the target is a rolling completion time until the rolling of all materials rolled through the heating furnace is completed, and it cannot be performed simultaneously in the rolling mill. These constraints are formulated into an optimization problem. Next, in step S5, the formulated optimization problem is converted into a mixed integer programming problem, and the material extraction order from the heating furnace and the rolling in the rolling mill are performed so that the rolling completion time is minimized. Determine the order.
JP 2000-167610 A JP 2004-209495 A JP 2003-305508 A

  However, in the methods described in Patent Documents 1 and 2, the rolling order and the heating furnace charging order are optimized, but considering the rolling order based on a detailed pass schedule such as thick plate rolling. Not.

  In the method of Patent Document 3, a rolling schedule is created based on a rolling pass schedule, but the heating furnace is not considered.

  Therefore, the present invention reduces the residence time in a waste heating furnace while satisfying the slab in-furnace time for a plurality of types of slabs based on a detailed pass schedule in thick plate rolling. It is an object of the present invention to provide a heating furnace charging order determination method and an apparatus for determining the same that enable efficiency.

In order to solve the above problems, the present invention has the following features.
[1] slab size relating to a plurality of types of slabs to be rolled, roll chance classification classified according to the finished width and finished thickness of the slab, attribute data including a rolling type classified in correspondence with a rolling method of the slab, and Read the rolling constraint data describing the range of rolling positions of the slab set for each roll chance category,
Group slabs based on the read attribute data,
For the grouped slabs, create a small rolling group with slabs that can be combined based on the attribute data and rolling constraint data,
The created small rolling group is arranged in the rolling order in consideration of the rolling constraint data to create rolling order data,
Based on the created rolling order data, an initial charging order creation step for creating a charging order for each slab into the heating furnace;
From the rolling order data created in the initial charging order creation step, move the position of any slab or replace it with any other slab to create a rolling order and a heating furnace charging order, total rolling time and heating The objective function including the evaluation of the furnace extraction waiting time is calculated, and when the calculated objective function value is improved, the rolling order and heating performed by replacing the moving or any other slab Change to the furnace charging order, and further perform the same movement for other slabs or replace with other arbitrary slabs, repeat the improvement of the objective function, the rolling order and heating with a shorter total rolling time A heating furnace charging order determination method, comprising: a charging order improvement step for determining a heating furnace charging order with a shorter furnace extraction waiting time.
[2] The heating furnace charging order determination method according to [1], wherein the objective function in the charging order / rolling order improving step is calculated by the following equation (1).
Objective function = A x Total rolling time + B x Sum of slab extraction waiting time + C x Difference in end time between furnaces + Bonus function + Penalty function (1)
Here, A, B, and C represent weighting factors.
[3] slab size relating to a plurality of types of slabs to be rolled, roll chance classification classified according to the finished width and finished thickness of the slab, attribute data including a rolling type classified in association with a rolling method of the slab, and Read the rolling constraint data describing the range of rolling positions of the slab set for each roll chance category,
Group slabs based on the read attribute data,
For the grouped slabs, create a small rolling group with slabs that can be combined based on the attribute data and rolling constraint data,
The created small rolling group is arranged in the rolling order in consideration of the rolling constraint data to create rolling order data,
Based on the created rolling order data, initial charging order creating means for creating the charging order of each slab into the heating furnace,
From the rolling order data created by the initial charging order creation means, move the position of any slab or replace it with any other slab to create a rolling order and a heating furnace charging order, total rolling time and heating The objective function including the evaluation of the furnace extraction waiting time is calculated, and when the calculated objective function value is improved, the rolling order and heating performed by replacing the moving or any other slab Change to the furnace charging order, and further perform the same movement for other slabs or replace with other arbitrary slabs, repeat the improvement of the objective function, the rolling order and heating with a shorter total rolling time A heating furnace charging order determining device comprising charging order improving means for determining a heating furnace charging order with a shorter furnace extraction waiting time.
[4] The heating furnace charging order determination apparatus according to [3], wherein the objective function in the charging order improving means is calculated by the following equation (1).
Objective function = A x Total rolling time + B x Sum of slab extraction waiting time + C x Difference in end time between furnaces + Bonus function + Penalty function (1)
Here, A, B, and C represent weighting factors.
[5] A method for charging a steel plate into a heating furnace, wherein the steel plate is charged into the heating furnace based on the determined charging order using the heating furnace charging order determination method according to [1] or [2]. .
[6] A steel plate manufacturing method for manufacturing a steel plate using the method for charging into a heating furnace according to [5] above.

  According to the present invention, based on a detailed pass schedule in thick plate rolling, it is possible to reduce useless heating time while satisfying the heating time of a slab for a plurality of types of slabs, and further increase the efficiency of rolling. There are provided a heating furnace charging order determination method and a determination apparatus therefor.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  FIG. 1 shows an example of a distribution flow in a steelmaking factory and a plank factory to which a heating furnace charging order determination method and a heating furnace charging order determination apparatus according to the present invention are applied. In FIG. 1, a slab 2 cast by a continuous casting machine 1 in a steelmaking factory is conveyed by a trailer 3 to a slab yard 4 in a thick plate factory. Here, in the slab yard 4, the slab 2 that has been transported is piled up in units of roll chance sections (hereinafter also referred to as “RC sections”). The RC section is a section classified according to the finished width and finished thickness of the slab after hot rolling, for example, as shown in FIG. Note that the RC classification method can be set as appropriate according to equipment specifications, operation conditions, and the like, and is not limited to the case of FIG.

  The slabs 2 stacked in the slab yard 4 are charged into the heating furnace 5. FIG. 1 shows a case where two heating furnaces are installed, but the present invention can be applied even when one or more than three heating furnaces are installed. The slab 2 charged in the heating furnace 5 is classified into a plurality of sizes depending on the thickness of the slab. FIG. 3 shows an example of classification into three types according to the size of the slab. Since it cannot be extracted from the heating furnace until the residence time in the furnace satisfies the in-furnace time, it cannot be transported to the rolling mill in the next process, resulting in a vacancy and lowering the rolling efficiency. If the residence time is too long, energy is lost in the heating furnace. Therefore, by setting the in-furnace time according to the thickness of the slab and the slab temperature at the time of charging in advance, it is possible to reduce wasteful residence time while satisfying the in-furnace time of the slab.

  The slab 2 extracted after completion of heating in the heating furnace 5 is rolled by a rolling mill 6. The upper limit of the number of slabs that can be rolled is determined for the rolling roll 61 used in the rolling mill 6 according to the type of the rolling roll 61, and the rolling roll 61 is replaced when the upper limit is reached. For the slab to be rolled, the standard of the position (order) at which rolling can be performed is determined for each RC section between the upper limit values of the number of slabs that can be rolled immediately after replacement of the rolling roll 61. FIG. 4 shows an example illustrating the possible rolling positions for each RC section. In FIG. 4, the vertical axis represents the RC section, the horizontal axis represents the rolling position (the number of slabs to be rolled after the roll change), and 0 on the horizontal axis represents the timing immediately after the roll change. In FIG. 4, for example, in the case of RC section 0, the rolling position is rolled in the range from the p3th to the p6th, and a maximum of n0 can be rolled during this time. Moreover, as shown in FIG. 4, you may mix the slab of a different RC division in the part which the range of the rolling position has wrapped.

  In FIG. 5, an example of the processing flow of the heating furnace charging order determination method which concerns on this invention is shown. FIG. 6 shows an example of a functional block diagram of the heating furnace charging order determination apparatus 10 according to the present invention.

  Here, a computer or the like can be used as the heating furnace charging order determination device 10, and the initial charging order creation step (S1) and the charging order improvement step (S2) in FIG. This is performed by the charging order creation means 11 and the charging order improvement means 12. Further, the initial charging sequence creation step (S1) in FIG. 5 includes the grouping step (S11), the small rolling group creation step (S12), the rolling sequence creation step (S13), and the charging sequence creation step (S14). These are performed by grouping means (111), small rolling group creation means (112), rolling order creation means (113), and charging order creation means (114) of initial charging order creation means 11 in FIG.

  The present invention provides a heating furnace charging that maximizes rolling efficiency by creating a charging sequence that achieves high efficiency from the viewpoints of both rolling (rolling mill) and heating (heating furnace). The order is to be created. Here, from the viewpoint of rolling (rolling mill), the total rolling time is the minimum, that is, double rolling (waiting the slab in standby spaces provided on the front and rear surfaces of the rolling mill and rolling another slab Etc.) and overtaking rolling, and slabs of the same type of RC are lined up. Also, from the viewpoint of heating (heating furnace), the waiting time for slab extraction should be minimal, the same size slab should be heated in the same furnace as much as possible, the extraction end timing between multiple heating furnaces should be almost the same, etc. .

  Hereinafter, each step will be described in detail.

[Initial charging order creation step (S1)]
In this step (S1), an initial charging order is created so that efficient improvement can be made in the charging order improving step (S2) (charging order improving means 12). As shown in FIG. 5, this step (S1) is grouped in a grouping step (S11) for grouping slabs based on attribute data read with respect to a plurality of types of slabs to be rolled, and a grouping step (S11). About a slab, a small rolling group creation step (S12) for creating a small rolling group of slabs that can be combined based on attribute data and rolling constraint data, and a small rolling group created by the small rolling group creation step (S12) are rolled. Considering the constraint data, a rolling order creation step (S13) for creating rolling order data by arranging them in the rolling order, and a heating furnace for each slab based on the rolling order data created by the rolling order creation step (S13) A charging order creation step (S14) for creating a charging order for To. The grouping step (S11) is the grouping means 111 in FIG. 6, the small rolling group creation step (S12) is the small rolling group creation means 112 in FIG. 6, and the rolling order creation step (S13) is in FIG. In the rolling order creation means 113, the charging order creation step (S14) is performed by the charging order creation means 114 in FIG.

[Grouping step (S11)]
In this S11, first, slab sizes relating to a plurality of types of slabs to be rolled, which are slab data that is the material data for planning from the upper computer 9 that performs production management by inputting / outputting operation performance data and production plan data, etc. , Roll chance classification classified according to the finish width and finish thickness of the slab, attribute data including the rolling type classified corresponding to the rolling method of the slab, and the rolling position of the slab set for each roll chance classification The rolling constraint data describing the range is read and stored in storage means such as a database.

  The slab data is attribute data for each slab and has, for example, the items and data shown in FIG. 7 and is read for the number of slabs to be planned. Hereinafter, the contents of each item shown in FIG. 7 will be described.

-Slab number A number for identifying individual slabs.

-Slab size Since the in-furnace time in the heating furnace depends on the slab thickness, this example treats the slab thickness as the slab size.

・ RC classification (roll chance classification)
These are classified according to the finished width and finished thickness of the slab after hot rolling, for example, as shown in FIG.

-Mountain number The mountain number of the slab piled up in the slab yard.

・ Rolling thickness Thickness at the end of slab rolling.

-Rolling width The plate width at the end of slab rolling.

・ Rolling type Slab that needs to be cooled during rolling (slab that waits for a long time), that is, during overtaking rolling, for example, the lifting slab is lifted to a height that allows the subsequent slab to pass through, and the subsequent slab Can be preceded by a slab (hereinafter referred to as “lift material”), or slab that does not require cooling during rolling and can overtake the preceding slab (hereinafter referred to as “passing material”). Or slabs that can be double-rolled by using standby spaces on the front and rear surfaces of the rolling mill. (Hereinafter referred to as “double rolled material”). In this example, as shown in FIG. 8, it is handled as a code corresponding to each rolling type. In FIG. 8, since the number of overtaking materials changes according to the length of the cooling time, the number of lift materials is three.

・ Slab temperature The temperature of the slab charged into the furnace is used to calculate the in-furnace time.

The following items are data related to the path schedule described in the background art. The rolling time and temperature adjustment time for each process corresponding to the slab are calculated by the host system. In the rolling process, there are forming / developing and thickening processes, but some of them do not require the forming / deforming process. In this example, the data items are rolling processes 1, 2, 3, temperature adjustment times 1, 2, and so on. did.
・ Rolling process time 1
・ Temperature adjustment time 1
・ Rolling process time 2
・ Temperature adjustment time 2
・ Rolling process time 3
The rolling constraint data is data describing the range of the rolling position of the slab set for each roll chance section shown in FIG. 4 described above, and has data and items as shown in FIG. 9, for example. This data is extracted by the host computer 9 and the information of the slabs after rolling in the heating furnace is extracted, created based on the RC classification, and read from the host system.

  The heating furnace charging plan to be created is created so that rolling can be performed within the rollable range for each RC section given by the rolling constraint data.

  The contents of each item shown in FIG. 9 will be described below.

-RC category Data indicating the roll chance category.

・ Start position Rollable start position of the corresponding roll chance category.

・ End position Rollable end position of the corresponding roll chance category.

  Next, the read slab data is grouped. By grouping slab data, it is possible to efficiently create an initial charging order. An example of grouping is shown in FIG. The example shown in FIG. 10 is a case where the slabs are first grouped into three types by slab size, and further grouped for each RC section, and further grouped by rolling type. As a result of the grouping, data shown in FIG. 11 is created. In the group classification code, a code corresponding to each group is written. In this example, as shown in FIG. 12, a code corresponding to the combination of the slab size, the RC classification, and the rolling type was created and used as a code corresponding to each group.

[Small Roll Group Creation Step (S12)]
In S12, a small rolling group is created by combining the slab data grouped in S11 (see FIG. 11). At this stage, since rolling efficiency can be considered to some extent, it is possible to create an initial charging order that can be improved efficiently in the charging order improvement step (S2) (charging order improving means 12).

The combination can be determined by the following logic, for example.
(1) Combine slabs of the same slab size.
(2) Combine slabs with the same RC section. If it is impossible to combine slabs of the same RC section, slabs of RC sections that can be mixed are combined.
(3) Each of the lift materials 1, 2 and 3 is combined with an overtaking material corresponding to the number of overtaking materials shown in FIG.
(4) Double rolled material combines double rolled materials.
(5) If there is no slab to be combined, each slab is regarded as a small rolling group.

  An example of creating a small rolling group based on the above logic is shown in FIG. In the squares showing the slabs in the figure, the dark portions indicate the rolling process, the white portions indicate the cooling process, and the horizontal lengths indicate the respective times (the same applies hereinafter).

  FIG. 13A shows a state in which grouping is completed for each rolling type with respect to a group of RC section 0 of slab size A.

  FIG. 13B shows a state in which one slab is taken out from the rolling type group a and five slabs are taken out from the rolling type group e based on the logic (3). Next, the rolling order of the slabs taken from (a) to (f) is created.

  FIG.13 (c) is the example which created the rolling order from slab (I) to (F) by making rolling start time of slab (I) 0. In this example, the rolling order in which the slabs (b) to (f) overtake the slab (b) during the cooling process is over, but as shown in FIG. 13 (d), the slabs (b) to (f) ) Slabs may be simply arranged. Assume that the rolling order set created as described above is a small rolling group as shown in FIG. The dotted line in the figure is the small rolling group.

  FIG. 14 (a) shows an example of a small rolled group of double rolled material, and FIG. 14 (b) shows an example of a small rolled group of overtaking material when there is no lift material.

  FIG. 15 illustrates a state in which the creation of the small rolling group is completed in the group of RC section 0 having the slab size A.

  FIG. 16 shows an example of data output after the creation of the small rolling group is completed. The following items are added to the slab data of FIG.

・ Small rolling group number This is the identification number of the small rolling group.

・ Small rolling group rolling start order The rolling start order within the small rolling group.

[Rolling order creation step (S13)]
In this S13, the small rolling groups are arranged in accordance with the rolling constraint data (see FIG. 9) that describes the range of positions that can be rolled for each RC section, read in S11, for the small rolling groups created in S12. Create a rolling order. FIG. 17 shows an example arranged in the rolling order. In FIG. 17, A shows the rollable range for each RC section, and B shows small rolling groups arranged based on the rollable range of A. Moreover, what was enclosed with the dotted line has shown each small rolling group, and the slab in a small rolling group is located in order of rolling start. FIG. 18 shows a data output example after completion of the rolling order creation. The following items are added to the slab data of FIG.

-Rolling start order This is the number of the rolling start order.

[Charging order creation step (S14)]
In this S14, the order of charging the slabs into the heating furnace is created based on the rolling order created in S13. Hereinafter, an example of a method for assigning slabs to each heating furnace will be described with reference to FIG. Each furnace is configured so that slabs can be charged in two rows.
(1) First, as shown to Fig.19 (a), a slab is arranged in rolling order based on the rolling order produced by said S13. In FIG. 10A, what is indicated by A is a slab, and the numbers in it indicate the rolling order.
(2) Next, for the slabs arranged in (1) above, one slab is selected from the beginning of the rolling order, the in-furnace time of the selected slab, and the slab whose rolling order is slower than the selected slab Compared with the in-furnace time, the slab with the shortest in-furnace time is extracted from the slabs with the slow rolling order and paired. Here, as the in-furnace time in the heating furnace, the time shown in the above-described FIG. 3 (heating time necessary to reach the target temperature during extraction) can be used. In FIG. 19B, A shows the created pairs, and B shows the order of the created pairs.
(3) Next, the pair of slabs created in (2) above is allocated to No. 1 heating furnace (hereinafter referred to as No. 1 furnace) and No. 2 heating furnace (hereinafter referred to as No. 2 furnace). FIG. 19C shows the state of each heating furnace immediately before allocating a pair of slabs. A in FIG. 19C indicates that the battery is already loaded and allocated, and B in FIG. 19C indicates a position at which slab allocation is determined this time.

  Allocation to the No. 1 and No. 2 reactors is performed from the top in the order of creation for the slab pairs created in (2) above. For the first and second furnaces, the total of the slab in-furnace times in the portion A of FIG. 19 (c) is calculated and assigned to the smaller total value. If the total value is the same, if the sum is the same, it will be assigned to Unit 1.

  A slab is allocated to each heating furnace by the above (1) to (3). When there is only one heating furnace, the pairs created in (2) above may be allocated to the heating furnace in that order. When there are three or more heating furnaces, The sum of in-furnace times for heating furnaces may be compared and assigned in the same manner. FIG. 20 shows an example of the created initial charging order data. The initial charging order data is obtained by adding the following items to the rolling order data in FIG.

-Heating furnace number It is the number of the heating furnace in which the slab is charged.

-Heating furnace charging sequence This is the sequence number in which the slab is charged into the heating furnace.

  The following steps are performed with the rolling order created in the initial charging order creation step (S1) and the charging order in the heating furnace as the initial solution (initial charging order).

[Charging Order Improvement Step (S2)]
In this step (S2), with respect to the rolling order data created in the initial charging order creation step (S1), the position of an arbitrary slab is moved or replaced with another arbitrary slab, and the rolling order and heating furnace equipment are changed. If an objective function including the evaluation of total rolling time and heating furnace extraction waiting time (heating furnace residence time) is calculated and the numerical value of the calculated objective function is improved , Change the order of rolling and heating furnace charging in which the movement or other arbitrary slab was replaced, and perform the same movement or other arbitrary slab for other slabs, By repeating the improvement of the function, a rolling order with a shorter total rolling time and a heating furnace charging order with a shorter heating furnace extraction waiting time (heating furnace residence time) are determined.

Here, in this step (S2), the objective function can be calculated by the following equation (1).
Objective function = A x Total rolling time + B x Sum of slab extraction waiting time + C x Difference in end time between furnaces + Bonus function + Penalty function (1)
As shown in Equation (1), this objective function is configured to aim at minimizing the sum of the total rolling time, the slab extraction waiting time, and the end time difference between heating furnaces. In addition, the bonus function is a weight function that, for example, achieves overtaking rolling and collects slabs of the same type of RC section to improve the objective function, and the penalty function quantitatively evaluates satisfaction of the constraint condition. It is added to the objective function. Eventually, a solution with a penalty function of zero is adopted.

  Here, A, B, and C represent weighting factors. In addition, what is necessary is just to set suitably how many the numerical values of A, B, and C are set according to which item is evaluated preferentially. In general, it is preferable to evaluate the total rolling time with priority, and examples of the weighting factors of A, B, and C include A = 0.7, B = 0.2, and C = 0.1. It is preferable to do.

  The total rolling time of Formula (1) is a value represented by the sum of the rolling times for each of the small rolling groups, and specifically, the rolling order creation step (S1) in the initial charging order creation step (S1). In the rolling order created in S13), it refers to the time required from the time when the first small rolling group starts rolling until the last small rolling group finishes rolling.

  The slab extraction waiting time sum in Expression (1) is a value represented by the sum of the extraction waiting times in the same furnace unit.

When there are two heating furnaces, the difference in end time between the heating furnaces of the formula (1) is a value represented by the following formula (2).
End time difference between heating furnaces = | Furnace 1 extraction end time-Furnace extraction end time | (2)
In addition, when there are three heating furnaces, the value is represented by the following formula (2-1).
Δ1 = | Unit 1 extraction end time-Unit 2 extraction end time |
Δ2 = | Unit 1 extraction end time-Unit 3 extraction end time |
Δ3 = | No. 2 furnace extraction end time − No. 3 furnace extraction end time |
End time difference between heating furnaces = Δ1 + Δ2 + Δ3 (2-1)
In addition, in the case of four or more units, it can be similarly performed by taking the sum of the differences for all combinations of heating furnaces.

Moreover, the bonus function of Formula (1) can be expressed by the following Formula (3).
Bonus function = -a x Overtaking rolling realization bonus + b x RC section consolidation bonus + c x Slab size consolidation bonus + d x Rolling width leveling bonus + f x In-furnace time leveling bonus + g x Same mountain consolidation bonus + h × Heating furnace charging time compliance bonus (3)
Here, a, b, c, d, e, f, g, and h represent weighting coefficients.

  The overtaking rolling realization bonus of equation (3) is added according to the number of overtakings if overtaking rolling can be executed in the small rolling group. The higher the bonus, the better the evaluation.

  FIG. 21 shows a calculation example of the RC category aggregation bonus of the equation (3). FIG. 21 shows a state in which slabs are arranged in the rolling order. In the figure, A represents a slab, B represents an RC section of the slab, and C represents a rolling order. For the RC category aggregate bonus value, the adjacent slabs are compared with the RC category, and in the case of different RC categories, an evaluation value is calculated according to different conditions. Since the slab of number 1 is RC section 0 and the RC section of the slab of number 2 adjacent to number 1 is 2, the value is 20 from the example of the bonus value shown in FIG. Thereafter, the same calculation is performed, and a value obtained by adding the respective values is set as the value of the RC classification aggregation bonus in the equation (3). The RC category aggregation bonus is better evaluated as the value is smaller.

  FIG. 23 shows a calculation example of the slab size aggregation bonus of Expression (3). FIG. 23 shows a state in which pairs of slabs at the time of charging are arranged in the order of extraction from the heating furnace. In the figure, a indicates a pair of slabs, b indicates the slab size of each slab, and c is a number indicating the order of extraction. As the slab size aggregate bonus value, the slab sizes of the pairs are compared, and in the case of different slab sizes, the bonus value is calculated according to different conditions. Since the slabs of the pair of extraction order 1 have slab sizes A and C, the value is 20 from the example of the bonus value shown in FIG. Thereafter, the same calculation is performed, and the sum of each is used as the value of the slab size aggregation bonus in Equation (3). The slab size aggregation bonus is better evaluated as the value is smaller.

  An example of calculation of the rolling width leveling bonus of Equation (3) is shown in FIG. FIG. 25 shows a state in which slabs are arranged in the rolling order. In the figure, A represents a slab, B represents a rolling width of the slab, and C represents a number indicating a rolling order. As the rolling width leveling bonus value, an absolute value of a difference in rolling width between adjacent slabs is calculated, and an evaluation value corresponding to the calculated value is calculated. Since the slab of rolling order 1 has a rolling width of 3000 and the rolling width of the slab of rolling order 2 adjacent to the slab of rolling order 1 is 2000, the absolute value of the difference is 1000. From the example of the bonus value shown in FIG. 26, the rolling width leveling bonus value is 100. Thereafter, the same calculation is performed, and the sum of the values is set as the rolling width leveling bonus value in equation (3). A smaller value for this rolling width leveling bonus is a better evaluation.

  FIG. 27 shows a calculation example of the in-furnace time leveling bonus of Expression (3). FIG. 27 shows a state in which slab pairs at the time of charging are arranged in the order of extraction from the heating furnace. In the figure, A indicates a pair of slabs, B indicates the in-furnace time of each slab (for example, unit is minutes), C indicates the total in-furnace time of the pair of slabs, and D indicates the extraction order. Number. As the in-furnace time leveling bonus value, the absolute value of the difference in the in-furnace time of the pair of slabs before and after is calculated, and the bonus value is calculated according to the calculated value. The total in-furnace time of the pair in the extraction order 1 is 200, and the total in-furnace time of the pair in the extraction order 2 is 250, so the absolute value of the difference is 50. From the example of the bonus value shown in FIG. 28, the in-furnace time leveling bonus value is 10. Thereafter, the same calculation is performed, and the sum of each is used as the in-reactor time leveling bonus value in Equation (3). The smaller the value of the in-furnace time leveling bonus, the better the evaluation.

  FIG. 29 shows an example of calculation of the mountain consolidation bonus of equation (3). FIG. 29 shows a state in which slabs are arranged in the order of charging into the heating furnace. In the figure, A represents a slab, B represents a peak number on which each slab is stacked, and C represents a number indicating the order of charging into the heating furnace. The mountain numbers at the slab yards of adjacent slabs are compared, and if the mountain numbers are different, an evaluation value, for example, 10 is added. Since the mountain number in the charging order 1 is C11 and the mountain number in the charging order 2 is C12, the mountain consolidation bonus value is 10. Thereafter, the same calculation is performed, and the sum of each is used as the same mountain consolidation bonus value in Equation (3). The smaller this mountain consolidation bonus, the better the evaluation.

  The heating furnace charging time compliance bonus in equation (3) calculates the difference between the heating furnace charging scheduled time and the actual heating furnace charging time for each slab, and uses the sum as an evaluation value. This bonus is better evaluated as the value is smaller.

  Note that the above bonus function may be evaluated by a method in which the points to be deducted are reduced when the evaluation is high, or may be evaluated by a method in which the points to be added are increased when the evaluation is high.

In addition, the penalty function of Expression (1) is performed by adding a penalty according to the degree when the built-in reference position of the RC section is exceeded as shown in FIG. In the case of FIG. 30, when the incorporation range of the RC section is P _{1 to} P ₂ , when the position is shifted to a position P ₀ (where P ₀ <P ₁ ) outside the range, the following expression (4) The value given in is added as a penalty value.
Penalty value = D × (P ₁ −P ₀ ) ² (4)
In this step (S2), the improvement of rolling efficiency is evaluated by the objective function expressed by the above equation (1).

  First, in this step (S2), with respect to the rolling order data created in the initial charging order creation step (S1), the position of any slab is moved or replaced with any other slab, The heating furnace charging order is created, and the objective function (Equation (1)) including the evaluation of the total rolling time and the heating furnace extraction waiting time is calculated.

  Hereinafter, an example of the method for replacing the slab will be described with reference to the flowchart of FIG. 31 and FIGS. 32 and 33. Here, the replacement method is not limited to the procedure described below, and a method known as an iterative local search method (generally a method of repeating a neighborhood search) can be used.

[S201]
First, in S201 shown in the flowchart of FIG. 31, a random combination of a small rolling group and a slab is created. Here, as shown in FIG. 32, for all slabs, combinations with all small rolling groups to which the slab does not belong are created, and the combinations are arranged in a random order.

[S202]
Next, in S202, recalculation of slab movement, rolling order, and heating furnace charging order is performed. Here, as shown in FIG. 33, based on the combination order created in S201, the corresponding slab is moved to the combined small rolling group. Then, with the change of the rolling order of the small rolling group at the moving destination and the small rolling group at the moving source, the rolling order in the small rolling group and the entire heating furnace charging order are recalculated.

[S203]
Next, in S203, it is determined whether or not the movement in S202 satisfies the above-described constraint conditions. Here, if the above restriction condition is not satisfied due to the movement (No), the process proceeds to S204, the moved slab is returned to the original, the process returns to S202, and the same movement operation is performed with the next combination. Try. If it is determined that the movement of the slab satisfies the above-described constraint condition (Yes), the process proceeds to S205.

[S205]
If it is determined in S203 that the movement of the slab satisfies the above-described constraints, the objective function is calculated in S205. Here, the value of the objective function expressed by the above equation (1) is calculated before and after the slab is moved.

[S206]
Next, in S206, it is determined whether or not the objective function is improved after the movement from the values of the objective function before and after the movement of the slab calculated in S205. If the value of the objective function is improved after the movement, that is, if a better value solution is obtained by the movement (Yes), it is determined that the movement is successful, and the process proceeds to the next S207. If the objective function is not improved after the movement (No), the process proceeds to S208.

[S207]
In this S207, the improved solution is left as the best solution for the movement determined to have obtained a better value solution by the movement in S206, and the process returns to S202, and the following combination is performed. Try a similar move operation.

[S208]
In this S208, it is determined whether or not the process of moving a slab other than the moved slab has been performed twice for the movement in which the objective function is determined not to be improved after the movement in S206. If it has not been performed twice yet (No), the process proceeds to S209 below. If it has already been performed twice (Yes), the process proceeds to S210.

[S209]
In S209, the slab other than the moved slab is moved to the one determined in S208 that the slab other than the moved slab has not been moved twice. As shown in FIG. 34, the movement here is performed by randomly selecting slabs other than the slabs that have moved in the movement destination small rolling group and moving them one by one to the movement source small rolling group. As for the rolling order after this movement, the process returns to S205 and the subsequent steps are repeated.

[S210]
In this S210, it is determined whether or not all the combinations have been improved with respect to what has been determined that the movement of the slab other than the moved slab has already been performed twice in S208. If all the combinations have not been evaluated yet (No), the process proceeds to S204, the moved slab is returned to the original state, the process returns to S202, and the same moving operation is tried with the next combination. If all combinations have been evaluated (Yes), the process proceeds to S211.

“S211]
In S211, when it is determined in S210 that all combinations have been evaluated, the best solution, that is, the output in the optimum heating furnace charging order is performed. Here, the optimum heating furnace charging order is the one having the best evaluation with a penalty value of zero in the objective function expressed by the above equation (1).

  In addition, when all the movement processes are unsuccessful in all “random orders”, there is no solution that can further improve the initial solution created by the initial charging order creation step (S1). The output is performed on the assumption that the heating furnace is in the optimal charging order. An example of the output result is shown in FIG. A heating furnace charging scheduled time and a heating furnace extraction scheduled time are added to the output example of the initial charging order (see FIG. 20).

  The output of the optimum heating furnace charging order may be displayed on the display means or the like of the heating furnace charging order determining device according to the present invention, or may be output to a host computer that performs production management. .

  In the processes of S201 to S211, it is necessary to recalculate the rolling order in the small rolling group every time the slab moves. In the present invention, since the recalculation of the rolling order within the small rolling group occurs frequently, the speed of the rolling order recalculation can be increased by the following method.

  An example of a method for speeding up the rolling order recalculation will be described with reference to FIG. Here, consider the case where the slab A has been moved to the small rolling group (n) as shown in FIG.

  First, as shown in FIG. 36 (b), the insertion position of the slab A within the small rolling group (n) is determined. In this determination, a random number corresponding to the number of slabs in the small rolling group is generated, and slab A is inserted after the rolling of the slab corresponding to the generated number is started.

  Next, as shown in FIG. 36C, the rolling position in the small rolling group (n) is recalculated based on the determined charging position.

  As described above, it is possible to speed up the recalculation of the rolling order.

  As described above, in the present invention, by optimizing the rolling order and the charging order of the heating furnace, based on the detailed pass schedule in thick plate rolling, the slab in-furnace time for multiple types of slabs It is possible to reduce useless residence time while satisfying the above, and to improve the efficiency of rolling.

Using the heating furnace charging order determination method according to the present invention, simulation was performed by applying to the actual data in actual operation. This simulation was performed under the following premise.
(A) In the heating furnace, data for the furnace length already exists in the furnace, and the charging order from the continuation is created.
(B) Since the actual temperature adjustment time has an operator's manual intervention factor (selection of water cooling or air cooling), the air cooling temperature adjustment time calculated using the temperature adjustment time calculation program was used.
(C) The batch furnace material was excluded from the simulation data, and only the data charged in the continuous furnace was used.

  Table 1 shows the results of the simulation for two cases, Case 1 and Case 2. In Table 1, the actual value is 100%, and the value of what percentage is obtained by the simulation is shown.

  As shown in Table 1, it was confirmed that the rolling time can be shortened by using the present invention, and the efficiency of rolling can be improved.

It is a figure which shows an example of the physical distribution flow in the steelmaking factory and thick board factory to which the heating furnace charging order determination method and heating furnace charging order determination apparatus which concern on this invention are applied. It is a figure which shows an example of the classification | category of the roll chance classification based on this invention. It is a figure which shows the relationship between the slab temperature at the time of charging to a heating furnace at the time of classifying into three types according to the size of the slab concerning the present invention, and the heating time until it becomes the extraction target temperature. It is a figure which shows an example of the rollable position for every roll chance division which concerns on this invention. It is a figure which shows an example of the processing flow of the heating furnace charging order determination method which concerns on this invention. It is a figure which shows an example of the functional block diagram of the heating furnace charging order determination apparatus which concerns on this invention. It is a figure which shows an example of the item of attribute data for every slab of this invention, and data. It is a figure which shows an example of the data structure of the rolling classification based on this invention. It is a figure which shows an example of the data which described the range of the rolling position of the slab set for every roll chance division based on this invention. It is a figure which shows an example of the grouping in the initial charging order creation step which concerns on this invention. It is a figure which shows an example of the data produced by the grouping in the initial charging order creation step which concerns on this invention. It is the figure which showed the response | compatibility of the group division code according to the combination of the slab size, RC division, and rolling classification which concerns on this invention. It is a figure which shows an example of the small rolling group preparation in the initial charging order preparation step which concerns on this invention. It is a figure which shows another example of small rolling group creation in the initial charging order creation step which concerns on this invention. It is a figure which shows another example of small rolling group creation in the initial charging order creation step which concerns on this invention. It is a figure which shows an example of the data output after the creation of the small rolling group which concerns on this invention is completed. It is a figure which shows an example in the case of producing a rolling order based on rolling restriction data for the small rolling group created in the small rolling group creation step according to the present invention. It is a figure which shows an example of the data output after completion of rolling order preparation which concerns on this invention. It is explanatory drawing for demonstrating an example of the allocation method of the slab to each heating furnace about the case where the heating furnace which concerns on this invention is 2 units | sets of No. 1 furnace and No. 2 furnace. It is a figure which shows an example of the initial charging order data produced | generated by the charging order creation step which concerns on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the roll chance division | segmentation aggregation bonus which concerns on this invention. It is a figure which shows an example of the bonus value of the roll chance division | segmentation bonus based on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the slab size aggregation bonus based on this invention. It is a figure which shows an example of the bonus value of the slab size aggregation bonus which concerns on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the rolling width leveling bonus which concerns on this invention. It is a figure which shows an example of the bonus value of the rolling width leveling bonus which concerns on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the in-furnace time equalization bonus based on this invention. It is a figure which shows an example of the bonus value of the in-furnace time leveling bonus which concerns on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the same mountain aggregation bonus which concerns on this invention. It is explanatory drawing for demonstrating an example of the calculation method of the penalty function which concerns on this invention. It is a flowchart for demonstrating an example of the replacement | exchange method of the slab in the charging order improvement step which concerns on this invention. It is explanatory drawing for demonstrating an example of the replacement | exchange method of the slab in the insertion order improvement step which concerns on this invention. It is explanatory drawing for demonstrating an example of the replacement | exchange method of the slab in the insertion order improvement step which concerns on this invention. It is explanatory drawing for demonstrating an example of the replacement | exchange method of the slab when the value of the objective function after the movement in the insertion order improvement step which concerns on this invention is not improved compared with before the movement. It is a figure which shows an example of the optimal heating furnace charging order output result produced at the charging order improvement step which concerns on this invention. It is explanatory drawing for demonstrating an example of the speed-up method of the rolling order recalculation which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Continuous casting machine 2 Slab 3 Trailer 4 Slab yard 5 Heating furnace 6 Rolling machine 61 Rolling roll 9 Host computer 10 Heating furnace charging order determination apparatus 11 Initial charging order creation means 12 Loading order improvement means

Claims (6)

Slab size for multiple types of slabs to be rolled, roll chance categories classified according to slab finish width and finish thickness, attribute data including rolling types classified according to slab rolling methods, and roll chances Load rolling constraint data describing the range of slab rolling positions set for each category,
Group slabs based on the read attribute data,
For the grouped slabs, create a small rolling group with slabs that can be combined based on the attribute data and rolling constraint data,
The created small rolling group is arranged in the rolling order in consideration of the rolling constraint data to create rolling order data,
Based on the created rolling order data, an initial charging order creation step for creating a charging order for each slab into the heating furnace;
From the rolling order data created in the initial charging order creation step, move the position of any slab or replace it with any other slab to create a rolling order and a heating furnace charging order, total rolling time and heating The objective function including the evaluation of the furnace extraction waiting time is calculated, and when the calculated objective function value is improved, the rolling order and heating performed by replacing the moving or any other slab Change to the furnace charging order, and further perform the same movement for other slabs or replace with other arbitrary slabs, repeat the improvement of the objective function, the rolling order and heating with a shorter total rolling time A heating furnace charging order determination method, comprising: a charging order improvement step for determining a heating furnace charging order with a shorter furnace extraction waiting time. The heating furnace charging order determination method according to claim 1, wherein the objective function in the charging order / rolling order improving step is calculated by the following equation (1).
Objective function = A x Total rolling time + B x Sum of slab extraction waiting time + C x Difference in end time between furnaces + Bonus function + Penalty function (1)
Here, A, B, and C represent weighting factors. Slab size for multiple types of slabs to be rolled, roll chance categories classified according to slab finish width and finish thickness, attribute data including rolling types classified according to slab rolling methods, and roll chances Load rolling constraint data describing the range of slab rolling positions set for each category,
Group slabs based on the read attribute data,
For the grouped slabs, create a small rolling group with slabs that can be combined based on the attribute data and rolling constraint data,
The created small rolling group is arranged in the rolling order in consideration of the rolling constraint data to create rolling order data,
Based on the created rolling order data, initial charging order creating means for creating the charging order of each slab into the heating furnace,
From the rolling order data created by the initial charging order creation means, move the position of any slab or replace it with any other slab to create a rolling order and a heating furnace charging order, total rolling time and heating The objective function including the evaluation of the furnace extraction waiting time is calculated, and when the calculated objective function value is improved, the rolling order and heating performed by replacing the moving or any other slab Change to the furnace charging order, and further perform the same movement for other slabs or replace with other arbitrary slabs, repeat the improvement of the objective function, the rolling order and heating with a shorter total rolling time A heating furnace charging order determining device comprising charging order improving means for determining a heating furnace charging order with a shorter furnace extraction waiting time. The heating furnace charging order determining apparatus according to claim 3, wherein the objective function in the charging order improving means is calculated by the following equation (1).
Objective function = A x Total rolling time + B x Sum of slab extraction waiting time + C x Difference in end time between furnaces + Bonus function + Penalty function (1)
Here, A, B, and C represent weighting factors.   The charging method of the steel plate to the heating furnace which charges a steel plate into a heating furnace based on the determined charging order using the heating furnace charging order determination method of Claim 1 or 2.   The steel plate manufacturing method which manufactures a steel plate using the charging method to the heating furnace of Claim 5.

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