JP2021111086A - Manufacturing schedule deciding device, manufacturing schedule deciding method and program - Google Patents

Abstract

To suppress an increase in manufacturing costs inherent to the change in the steel type while collecting casts with the change in the steel type being taken into consideration, and to decide a further appropriate manufacturing schedule.SOLUTION: Provided is a manufacturing schedule deciding device which is for a continuous casting process of manufacturing cast products, and which includes: a data input unit into which data is input, the data containing specification information on a cast product including a steel type, and information on a cast that is a unit of continuously manufacturing the cast product; a tentative schedule deciding unit that tentatively decides the manufacturing schedule for the cast product on the basis of the specification information on the cast product, the information on the cast, and a restriction condition on the process; and a schedule correcting unit that corrects the manufacturing schedule by changing a first cast product included in the tentatively decided manufacturing schedule to a second cast product which has a higher manufacturing priority, and which has another steel type that can be changed with the steel type of the first cast product.SELECTED DRAWING: Figure 3

Description

The present invention relates to a manufacturing schedule determining device, a manufacturing schedule determining method and a program.

In the steel manufacturing process, pig iron manufactured in a blast furnace is transported to a converter, and after the composition is adjusted in pot (charge) units in the converter, the molten steel poured into the tundish is continuously cooled and cut. Manufactures castings called, slabs, blooms, or billets. At this time, the process of continuously cooling and cutting is called a continuous casting process, and the unit for continuously manufacturing a cast product is called a cast, and casting is performed based on a predetermined size, quality, delivery date, etc. of the cast product. The work of determining the order (manufacturing schedule) is called casting.

Here, the target value of the composition of the molten steel when adjusting the composition of the molten steel in units of pots (charges) in the converter is determined according to the steel type specified for each cast product. The permissible component composition range differs depending on the steel type. For example, the permissible component composition range is narrow for the upper steel type, and the permissible component composition range is wide for the lower steel type. In addition to the steel grades that are in the upper / lower relationship, there are also steel grades that have similar composition ranges, so it is often possible to manufacture cast products that meet the order specifications of a certain final product with multiple steel grades. That is, in a cast product, there are often a plurality of castable steel grades capable of manufacturing the cast product, in addition to the "original steel grade" that is optimal in terms of manufacturing. In this regard, when considering cast knitting, it is sufficient if the cast can be knitted only with cast products of the same steel type, but there are hundreds of steel types specified for each cast product, and the total may exceed 1,000 types. , Not realistic. Therefore, a method called diversion or tying, in which a castable steel grade other than the "original steel grade" is used, is known. Since the order specifications for cast products do not specify the steel type itself, but the component composition range, the order specifications are satisfied even if the product is manufactured with a castable steel type other than the "original steel type". No problem occurs. Increasing the concentration of casts (increasing the lot size) with such higher standards and alternative castable steel grades may reduce the average manufacturing cost of individual products. Patent Document 1 describes a technique for more efficiently manufacturing a product by increasing the degree of aggregation of casts by such a method.

Japanese Unexamined Patent Publication No. 2018-14420

However, if the manufacturing schedule is determined so that the substitutable steel grades are simply combined into the same cast, the lower standard steel grades are incorporated into the cast of the higher standard steel grades, but the reverse does not occur. There is a possibility that only casts will increase. Higher standard steel grades have high manufacturing costs due to, for example, a narrow allowable composition range, so simply grouping substitutable steel grades into the same cast may consolidate the cast but increase the manufacturing cost. be.

Therefore, the present invention is a manufacturing schedule determination device and manufacturing capable of suppressing an increase in manufacturing cost due to replacement of steel grades and determining a more appropriate manufacturing schedule while consolidating casts in consideration of substitution between steel grades. It is intended to provide a scheduling method and program.

According to a certain aspect of the present invention, it is a manufacturing schedule determination device in a continuous casting process for manufacturing a cast product, and specification information of the cast product including a steel grade, and information on a cast which is a unit for continuously manufacturing a cast product. A data entry unit for inputting data including Schedule modification to modify the manufacturing schedule by replacing the first casting product included in the schedule with a second casting product of another steel grade that has a higher manufacturing priority and can replace the steel grade of the first casting product. A manufacturing schedule determination device including a unit is provided.

According to another aspect of the present invention, the manufacturing schedule determination method in the continuous casting process for manufacturing a cast product, the specification information of the cast product including the steel type, and the cast which is a unit for continuously manufacturing the cast product. A data entry step in which data containing information is entered, a tentative schedule determination step that tentatively determines the manufacturing schedule of the cast product based on cast product specification information, cast information, and process constraints, and tentatively determined. A schedule for modifying the production schedule by replacing the first cast product included in the production schedule with a second cast product of another steel type that has a higher production priority and can replace the steel type of the first cast product. A manufacturing schedule determination method including correction steps is provided.

According to yet another aspect of the present invention, it is a program for determining a production schedule in a continuous casting process for producing a cast product, and specifications information of the cast product including a steel grade and continuous production of the cast product. A data entry unit that inputs data including information about the cast, which is a unit, a tentative schedule determination unit that tentatively determines the manufacturing schedule of the casting product based on the specification information of the cast product, the information about the cast, and the constraint conditions in the process. And the first cast product included in the tentatively determined production schedule is manufactured by replacing the steel grade of the first cast product with a second cast product of another steel grade which has a higher production priority and can be replaced. A program for operating a computer is provided as a schedule correction unit for modifying a schedule.

According to the above configuration, by considering at the schedule revision stage after the manufacturing schedule is tentatively decided, the cast is aggregated in consideration of the substitution between the steel grades, and the increase in the manufacturing cost due to the substitution of the steel grade is suppressed. , A more appropriate manufacturing schedule can be determined.

It is a figure which conceptually shows the manufacturing schedule in a continuous casting process. It is a figure which conceptually shows the result of allocating a slab to a strand according to the manufacturing schedule shown in FIG. It is a figure which shows the schematic structure of the manufacturing schedule determination apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the schematic process of the manufacturing schedule determination method which concerns on one Embodiment of this invention. It is a figure which shows an example of the slab information file used in the example of FIG. It is a figure for demonstrating the alternative relationship between steel grades. It is a figure which shows the example of the situation which may occur by the substitution of a steel grade. It is a figure which shows an example of the same steel type cast information file used in the example of FIG. It is a flowchart which shows the example of the process which determines the shape of a cast in the example of FIG. It is a figure for conceptually explaining the candidate set extraction process in the example of FIG. It is a figure for conceptually explaining the candidate set extraction process in the example of FIG. It is a figure for conceptually explaining the network generation process and the optimum solution calculation process in the example of FIG. It is a figure for conceptually explaining the network generation process and the optimum solution calculation process in the example of FIG. It is a figure which shows the example of the process of the steel type substitution determination in the example of FIG. It is a figure for demonstrating the difference between sequential processing and batch processing in determining a manufacturing schedule. It is a figure for demonstrating the difference between sequential processing and batch processing in determining a manufacturing schedule.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

FIG. 1 is a diagram conceptually showing a production schedule in a continuous casting process. In the example shown in FIG. 1, the production schedule of the slab sets 1A, 1B, 1C, which are cast products produced from molten steel in the continuous casting process, is determined. Here, the molten steel is injected into a container called a ladle, undergoes a secondary refining process, and is then conveyed to a continuous casting process. The amount of molten steel for a full ladle is called a charge. In the illustrated example, the same steel type cast 11A is composed of two charges of the same component composition of charges 10A1 and 10A2, and similarly, the same steel type cast 11B has three charges of 10B1, 10B2, 10B3, and the same steel type cast 11C. Is composed of two charges of 10C1 and 10C2.

Here, the continuous casting step of the present embodiment is continuous casting of different steel types in which the component compositions of the casts 11A, 11B, and 11C of the same steel type are different from each other. That is, the composition of the components is different among the plurality of casts 11A, 11B, and 11C of the same steel type contained in all the casts 12 that are continuously cast from the tundish exchange to the next tundish exchange in the continuous casting machine. In the present embodiment, the production schedule of the slab sets 1A, 1B, 1C is determined in each of the casts 11A, 11B, and 11C of the same steel type having the same composition of the molten steel. In the present embodiment, the steel grade casts 11A, 11B, 11C constitute a unit for continuously producing slabs.

FIG. 2 is a diagram conceptually showing the result of allocating slabs to strands according to the production schedule shown in FIG. The continuous casting apparatus contains one or more strands for one tundish. The strands include a mold into which molten steel is poured from the tundish and a series of molding rolls that are molded while transporting the slabs drawn from the mold. In the illustrated example, the continuous casting apparatus is composed of strands A and B. Each charge 10 is supplied to both the two strands A and B as shown by the broken line, and the slab 1 is cast separately on the respective strands A and B. Therefore, in the illustrated example, the slab 1 is assigned to each of the same steel type casts 11 (same steel type casts 11A, 11B, ...) Treated separately for each of the strands A and B, and the production schedule is determined.

Here, in the example shown in FIG. 2, the width and length of the slab 1 are different from each other. The width of the slab 1 can be changed by adjusting the width of the mold in each of the strands A and B. In addition, in terms of equipment restrictions and quality, the slabs 1 are arranged in the same steel type cast 11 so that the width of the slabs 1 is gradually expanded or contracted. On the other hand, the length of the slab 1 can be changed by adjusting the position of cutting the slab after molding with the molding roll. In the present embodiment, the slabs located at the seams of different charges 10 in the same steel type cast 11 are referred to as the same steel type seam slab 1P, and the slabs located at the seams between the same steel type casts 11 are referred to as different steel type seam slabs 1Q. ..

FIG. 3 is a diagram showing a schematic configuration of a manufacturing schedule determination device according to an embodiment of the present invention. The production schedule determination device 100 may be implemented as application software in, for example, a dedicated computer system or a general-purpose computer system such as a personal computer. Alternatively, each component of the manufacturing schedule determination device 100 may be distributed and implemented in a plurality of computers connected via a network such as a LAN (Local Area Network) or the Internet. The manufacturing schedule determination device 100 includes a data input unit 110, a provisional schedule determination unit 120, and a schedule correction unit 130. The functions of each of these parts are realized by a processor that operates according to a program and an interface for inputting and outputting data to and from the processor.

The slab information file 101 and the steel grade cast information file 102 used by the manufacturing schedule determination device 100 for processing are read by an operation by an operator, an automatic intake instruction at a fixed time, or the like. The manufacturing schedule determination device 100 records the result of the processing executed based on the information recorded in these files in the cast organization result file 104. Further, the manufacturing schedule determination device 100 reads the organization condition file 105 in the processing executed by the provisional schedule determination unit 120 and the schedule correction unit 130. These files are recorded, for example, in a memory built into the computer or a removable recording medium that can be connected to the computer. Further, any or all of the above files are stored in an information processing device different from the manufacturing schedule determining device 100, and the manufacturing schedule determining device 100 is stored via communication using a telecommunication line such as LAN or the Internet. It may be read into or written by the manufacturing schedule determination device 100.

FIG. 4 is a flowchart showing a schematic process of a manufacturing schedule determination method according to an embodiment of the present invention. The process shown in FIG. 4 is performed, for example, before the steel mill receives the molten steel. In the illustrated example, first, in the data input step S110, the data input unit 110 continuously transfers the specification information (slab information file 101) of the slab which is the cast product in the present embodiment and the cast product in the present embodiment. Data including information about the cast, which is a unit to be manufactured (the same steel grade cast information file 102), is input. The slab information file 101 includes schedule information of the slab to be released from now on. Scheduled information includes (1) slab thickness, width, length, upper and lower limits of weight, manufacturing specifications such as steel grade, and (2) desired passing date and time of the next process, passing deadline date and time, urgent instruction information for urgent casting, etc. Includes process information. The same steel type cast information file 102 includes information regarding the charge for each same steel type cast. Specifically, this information includes the number and weight of charges in each cast of the same steel type, materials that can be manufactured, and the like.

FIG. 5 is a diagram showing an example of a slab information file used in the example of FIG. Although only some items are illustrated in FIG. 5 for the sake of simplicity, the slab information file 101 may include more items related to manufacturing specifications and process information in addition to the items shown. In the example shown in FIG. 5, one row represents one slab and is given a unique slab ID for identification. Among the illustrated items, "slab width" and "slab length" indicate the dimensions of the slab to be cast, and "slab weight" represents the weight of the slab to be cast. Further, the "steel grade" is information that defines an allowable range of the component composition of the slab and a casting method, and is represented by a code in the illustrated example. "Substitutable steel grade" is a code indicating another steel grade that satisfies the composition and casting method specified in the original steel grade, and the slab can be cast with a substitute steel grade instead of the original steel grade. Is.

Here, as shown in FIG. 6, for example, in terms of composition, the permissible range for each steel type overlaps with a plurality of steel types, and therefore one steel type (here, steel type A) is changed to another steel type (here, steel type A1). Can be replaced with. Further, when the specifications of the final product, for example, the tensile strength of the steel type A and the steel type B having similar composition, are satisfied, the steel type A can be replaced with the steel type B for production. However, since the manufacturing cost of a higher standard steel grade having a narrow allowable range of composition or a substitutable steel grade is generally high, it is not preferable that the slabs are concentrated in the substitutable steel grade as shown in FIG. 7, and the manufacturing cost. Therefore, it is desirable to manufacture with the original steel grade. The determination of the production schedule in consideration of such substitutable steel grades will be described later.

With reference to FIG. 5 again, in the slab information file, "desired passage date and time", "passage deadline date and time", and "urgent instruction information" are exemplified as process information. The "desired passage date and time" is the passage (for example, start) date and time of the hot rolling process, which is the next process, and is determined based on, for example, the delivery date and the production plan. The "passing deadline date and time" is the latest date and time of processing in the hot rolling process, which is the next process. "Urgent instruction information" is information on the delivery date of the slab, for example, "A" for a slab that is very urgent to proceed to the next process, "B" for an urgent one, etc., depending on the urgency of casting. Code is set.

FIG. 8 is a diagram showing an example of the same steel type cast information file used in the example of FIG. Although only some items are illustrated in FIG. 8 for the sake of simplicity, the steel grade cast information file 102 may include other items in addition to the items shown. In the example shown in FIG. 8, one row represents one same steel type cast, and a unique same steel type cast ID is given for identification. Among the illustrated items, the "charge number" indicates the number of charges 10 included in each cast of the same steel type. The “steel grade” is a steel grade (component composition) in each cast of the same steel grade, and has the same code as the “steel grade” and the “substitutable steel grade” in the example of the slab information file 101 shown in FIG. The "lower limit of weight" and "upper limit of weight" will be described later.

Returning to the description of FIG. 4 again, in the following steps S120 to S140, the provisional schedule determination unit 120 performs slab specification information (slab information file 101), cast specification information (same steel grade cast information file 102), and continuous. The production schedule of the slab in the continuous casting process is tentatively determined based on the process constraint conditions (knitting condition file 105) in the casting process.

First, in the cast shape provisional determination step S120, the provisional schedule determination unit 120 calculates the manufacturing schedule, specifically, the optimum solution of the cast shape, using the method of searching for the shortest path in the network as described below. do. As described above with reference to FIG. 2, in the continuous casting apparatus, the width of the slab can be changed, but due to equipment restrictions and quality, the provisional schedule determination unit 120 is of the same steel type. Arrange the slabs so that the width of the slabs gradually increases or decreases in the cast. The shape of the slabs arranged in the same steel type cast in this way is also referred to as the cast shape below.

FIG. 9 is a flowchart showing an example of a process of determining the shape of the cast in the example of FIG. First, in the candidate set extraction step S121, the provisional schedule determination unit 120 extracts information on the slab that can be manufactured by casting the same steel grade from the slab information file 101. When extracting, a slab having the same steel grade as the preset steel grade of the same steel grade cast frame is extracted. The slab extracted here will be referred to as a candidate slab below. From these candidate slabs, a set of slabs is extracted so that the total weight is close to the weight of a predetermined cast of the same steel type (hereinafter referred to as "candidate set extraction process"). Here, the weight of the same steel type cast is specified, for example, by the "weight lower limit" and the "weight upper limit" of the same steel type cast information file 102 described with reference to FIG. 8 above. Since there are multiple combinations of slabs, a plurality of slab sets are extracted. Using this as a candidate set, extraction of the candidate set is repeated for all casts of the same steel grade (step S122: No).

10 and 11 are diagrams for conceptually explaining the candidate set extraction process in the example of FIG. 9. FIG. 10 shows a flow of determining a candidate set corresponding to one cast of the same steel type. Candidate slabs extracted as slabs that can be produced by the same steel type cast are slabs S1 to S5. Of these, the slabs S2 and S4 are subject to thin material regulation in the rolling process in which the coil thickness after rolling is the subsequent process. The thin material regulation is a restriction on the number of slabs in a hot-rolled lot for producing a thin coil. In this example, it is assumed that the upper limit of the number of rolls that can be rolled in one rolling lot is one in accordance with the thin material regulation. Further, it is assumed that the "lower limit of weight" and the "upper limit of weight" of the same steel type cast in the example shown in FIG. 8 are 58 tons.

In such an example, the provisional schedule determination unit 120 first lists all the candidate sets having a total slab weight of about 60 tons. As shown in the figure, there are 10 candidate sets in which the total slab weight is around 60t, but 6 patterns have a total slab weight in the range of 58t to 62t. ”). If 2 patterns that do not conform to the thin material regulation (including both slabs S2 and S4; indicated as "number NG") are excluded from this, a candidate set of 4 patterns is extracted.

In fact, when all the candidate sets are listed in the extraction of the candidate sets as described above, the number becomes enormous (for example, when all the candidate sets including 15 slabs are listed from 50 candidate slabs, ₅₀ C ₁₅ ≈ (2.3 x 10 ¹² patterns), so it is necessary to narrow down by some rule, that is, to list them conditionally. Specifically, for example, in the slab information file 101 shown in the example of FIG. 5, only the candidate set containing many slabs in which "A" or "B" is set in the "urgent instruction information" may be listed. At this time, the provisional schedule determination unit 120 preferentially allocates the slab having a short delivery date to the production schedule. FIG. 11 shows an example of enumerating a candidate set when “A” is set in the “urgent instruction information” of the slab S1. In this case, if the candidate set that does not include the urgent material (slab S1) is extracted, the evaluation index described later becomes low. Therefore, by listing only the candidate set that always includes the slab S1, 6 patterns of 10 patterns in the case of all enumeration Can be narrowed down to.

Returning to the description of FIG. 9 again, when the candidate sets are extracted for all the same steel type casts by repeating the candidate set extraction steps S121 and S122 (step S122: Yes), the provisional schedule determination unit 120 sets the network generation step. In S123, a network for determining one slab set from each candidate set of the same steel grade cast is generated (hereinafter, referred to as “network generation process”). Next, in the optimum solution calculation step S124, the provisional schedule determination unit 120 calculates the optimum solution (one slab set) of the candidate set in each cast of the same steel type by using the search for the shortest path in the network (hereinafter, “1 slab set”). Optimal solution calculation process ").

12 and 13 are diagrams for conceptually explaining the network generation process and the optimum solution calculation process in the example of FIG. In the network illustrated in FIG. 12, each of the nodes a1, a2, ..., AN (first node) is a candidate set extracted for the same steel type cast 11A (first same steel type cast), that is, the same. The combinations of slabs that can be assigned to the production schedule within the steel grade cast 11A are shown. Similarly, each of the nodes b1, b2, ... BM (second node) is a candidate set extracted for the same steel type cast 11B (second same steel type cast), that is, the production schedule in the same steel type cast 11B. Shows the slab combinations that can be assigned to. Each of the nodes c1, c2, ..., CL (third node) is assigned to the production schedule within the candidate set extracted for the same steel type cast 11C (third same steel type cast), that is, the same steel type cast 11C. The possible combinations of slabs are shown. The edge of the network connects each of the nodes a1, a2, ..., AN and each of the nodes b1, b2, ... bM, and each of the nodes b1, b2, ... bM and the node c1, Connect each of c2, ..., CL.

The distance d (edge length) between the nodes in the network as described above is, for example, as shown in FIG. 13, an urgent material in the candidate set corresponding to the nodes on both sides of the edge (as described above, for example, "urgent instruction". The ratio of slabs with "A" and "B" set in "Information" and the width difference, that is, the difference between the minimum and maximum values of the slab width in the candidate set corresponding to the nodes on both sides of the edge. And the surplus rate, that is, the ratio of the surplus weight contained in the candidate set corresponding to the nodes on both sides of the edge (the difference between the total charge of molten steel weight in the cast of the same steel type and the total slab weight contained in the candidate set). Determined based on the evaluation index. In the illustrated example, the weights w1 to w3 to be multiplied by these evaluation indexes are set so that the distance d becomes smaller, for example, when the ratio of the urgent material is high, the width difference is small, and the surplus rate is low. Will be done. Next, the shortest path is found in the generated network. As described with reference to FIG. 13, in the present embodiment, the distance d (edge length) between the nodes is determined based on the evaluation index. Therefore, finding the shortest path in the above network is different for each. It is equivalent to selecting the most appropriate candidate set from the same steel type cast.

With reference to FIG. 4 again, in the embedded unit improvement step S130, there is a possibility that the provisional schedule determination unit 120 has not sufficiently extracted the optimum candidate set because it did partial enumeration instead of full enumeration in the candidate set extraction process. Adjust the manufacturing schedule in consideration of. Specifically, the provisional schedule determination unit 120 was not incorporated into the candidate set of the candidate set slabs selected in the cast shape provisional determination step S120 and the candidate slabs (slabs S1 to S5 in the example of FIG. 10). The slabs are sequentially compared with each other, and when the evaluation index is improved, the slabs of the candidate set are replaced with the slabs that are not included in the candidate set. Since the slab of the candidate set has already been selected in the cast shape provisional determination step S120, the amount of calculation for the above adjustment is not larger than the amount of calculation for selecting the candidate set (for example, When a candidate set including 15 slabs is selected from 50 candidate slabs, the number of times to compare the evaluation index for replacement with the remaining 35 slabs is 15 × 35 = 525 times).

In the next constraint violation resolution step S140, the provisional schedule determination unit 120 further adjusts the manufacturing schedule based on the process constraints in the continuous casting process. In the cast shape tentative determination step S120, not all the constraints in continuous casting are necessarily reflected. For example, in the candidate set extraction process and the optimum solution calculation process, selection is performed based on the evaluation index, and the conditions of the slabs arranged at the beginning and end of all casts 12 shown in FIG. 1 and the conditions of the slabs arranged in FIG. 2 are shown in FIG. No restrictions are imposed so that those that meet the conditions of the same steel type seam slab 1P and the different steel type seam slab 1Q shown are included. The constraint condition (whether or not the width of the mold can be smoothly changed) for the gap of the width of the continuous slab in the determined cast shape is also selected by the evaluation index so as to be small. Under these conditions, it is generally unlikely that the constraints will be met. Therefore, in the constraint violation resolution step S140, the provisional schedule determination unit 120 calculates the length and weight between the respective slabs arranged from the beginning to the end of all casts 12 and the continuous slabs, and as described above. It is determined whether or not the constraint conditions are satisfied. If the constraint condition is violated, an attempt is made to replace the slab with a slab that has not been incorporated into the selected candidate set, as in the embedded unit improvement step S130. If there are no replaceable slabs, insert an appropriate surplus slab into the cast to ensure that the constraints are met (eg, if the width gap between successive slabs is too large, the middle of the previous and next slabs. Insert a slab of the width of).

By the processing of the provisional schedule determination unit 120 up to step S140, it is possible to reflect the specification information of the slab and the information on casting, further satisfy the process constraints in the continuous casting process, and actually perform the casting. The production schedule is tentatively decided. In the following steps S150 and S160, the schedule correction unit 130 further optimizes the manufacturing schedule from the viewpoint of delivery date and cost, for example, by trying to correct the tentatively determined manufacturing schedule. Since it is possible to actually execute the casting according to the manufacturing schedule tentatively determined as described above, the schedule correction unit 130 may execute step S160 by omitting step S150, for example. Further, the schedule correction unit 130 may execute step S150 for the surplus slab after executing step S160 first.

In the surplus slab minimization step S150, the schedule correction unit 130 attempts to modify the manufacturing schedule from the viewpoint of minimizing the weight of the surplus slab. Since the surplus slab inserted into the cast in the above constraint violation solving step S140 is originally an unnecessary slab, it is preferable that the weight is small. Therefore, the connectivity with the slabs before and after the surplus slab is verified, and an attempt is made to reduce the weight of the surplus slab within a range that does not conflict with the constraint conditions considered in the constraint violation solving step S140 again.

On the other hand, in the steel grade substitution determination step S160, the schedule correction unit 130 attempts to correct the manufacturing schedule in consideration of the possibility of substitution between the steel grades of the slab. Specifically, as shown in FIG. 14, the schedule correction unit 130 has another slab 1X included in the tentatively determined production schedule, which has a higher production priority and can replace the steel grade of the slab 1X. Attempt to replace with steel grade slab 1Y. In addition, even in the steel type substitution determination step S160, when replacing the slab, it is a condition that the constraint condition in the process such as the width difference considered up to the constraint violation elimination step S140 is satisfied.

The production priority may be determined based on, for example, the expiration date of the next step of the slab, or the urgency of the slab. In the case of the present embodiment, the passing deadline of the next step is indicated by, for example, the "desired passing date and time" and the "passing deadline date and time" among the items of the slab information file 101 shown in the example of FIG. The schedule correction unit 130 may determine the manufacturing priority based on, for example, the context of the passing deadline. Further, the degree of urgency is indicated by "urgent instruction information" in the example of FIG. The schedule correction unit 130 may determine the manufacturing priority based on, for example, the magnitude relationship of the urgency indicated by the code of the "urgent instruction information". Further, the steel grades capable of substituting the steel grade of the slab 1X are indicated by "substitutable steel grades" in the example of FIG.

Since the surplus slab inserted into the cast in the constraint violation resolution step S140 is a slab that does not originally need to be manufactured, it does not exist in the slab information file 101, for example, and the passage deadline and urgency of the next process are set. do not have. In such a case, the schedule correction unit 130 may determine that the production priority of the slab is the lowest. Alternatively, the schedule correction unit 130 may attempt to preferentially replace the surplus slab with another slab of another steel grade that can be replaced.

Here, in the steel grade substitution determination step S160, the schedule correction unit 130 replaces the slabs in consideration of the alternative steel grade by determining the number or weight of the slabs (slab 1Y shown in FIG. 14) replaced in the cast. It may be executed until the upper limit is reached. A predetermined upper limit may be set, for example, for the number or weight of replaced slabs in the cast, or the ratio of the number or weight of replaced slabs to all slabs in the cast. Since the original steel grade of the slab is usually determined to have the lowest manufacturing cost within the range that meets the order specifications, the manufacturing cost as a whole can be obtained by casting with an alternative steel grade without any limitation even if the manufacturing priority is high. May rise. Therefore, setting the upper limit as described above controls the trade-off between the decrease in manufacturing cost due to the increased cast intensity and the increase in manufacturing cost due to the production with alternative steel grades, and the overall manufacturing cost is reduced. It is useful for suppressing the rise. Even if the upper limit is not reached, if there are no more replaceable slabs, the schedule modification will end.

Further, the schedule correction unit 130 may execute the replacement only when the amount of increase in the manufacturing cost of the slab 1Y due to the replacement of the slab 1X with the slab 1Y is less than the threshold value. As a result, for example, even if it is substitutable, it is not easily manufactured by the same steel type cast of the higher standard with a narrow permissible range of component composition and high manufacturing cost, but the increase in manufacturing cost is as low as possible in the substitutable category. It is possible to incorporate the decision to preferentially replace standard slabs for casting. The schedule correction unit 130 replaces the slab by scoring the above-mentioned manufacturing priority and comparing the total score calculated as the weighted linear sum of the manufacturing priority score and the increase amount of the manufacturing cost with the threshold value. It may be determined whether or not the slabs are to be replaced, and the priority of the slabs to be replaced may be determined according to the magnitude relationship of the overall score.

By determining the slab production schedule in the continuous casting process in the above steps, the slab specification information, cast specification information, constraints on the production schedule in the continuous casting process, and alternative relationships between steel grades are taken into consideration. NS. Therefore, it is possible to determine a manufacturing schedule that fully reflects the required specifications and constraints in the continuous casting process. In addition, regarding the substitution relationship between steel grades, the cast is aggregated in consideration of the substitution between steel grades by considering the production schedule that can actually perform casting at the schedule revision stage after the production schedule is tentatively determined. At the same time, it is possible to suppress an increase in manufacturing cost due to substitution of steel grade and determine a more appropriate manufacturing schedule.

15 and 16 are diagrams for explaining the difference between the sequential processing and the batch processing in determining the manufacturing schedule. FIG. 15 shows an example in which the cast shape is sequentially determined for each cast (cast of the same steel type in the above embodiment) as described in, for example, Japanese Patent No. 5928521. In this case, first, a process of determining the cast shape of the steel type A is executed, and the cast shape is selected based on the number of width transitions when, for example, slabs are assigned to each of the two strands. In the illustrated example, a cast shape having four width shifts and a cast shape having two width shifts are extracted as candidates, and two cast shapes with a smaller width shift are selected. Next, a process of determining the cast shape of the steel type B is executed. However, as shown in the figure, since the slab cast by the steel type B is only a narrow slab, the slab cast by the steel type A has a wide slab. Can not be connected to the strand A in which the above is aggregated due to the limitation of the width shift amount, and in the casting of the steel type B, there occurs a situation in which there is no slab assigned to the strand A.

On the other hand, FIG. 16 shows an example in which a schedule for continuously casting a cast corresponding to a steel type A and a cast corresponding to a steel type B is collectively determined as in the above-described embodiment of the present invention. Has been done. In this case, the cast shape of the steel type A and the cast shape of the steel type B are determined at the same time. In the illustrated example, the cast shape has four width shifts in the cast of steel type A and four width shifts in the cast of steel type B, and two width shifts in the cast of steel type A and the cast of steel type B. Cast shapes with two width shifts in the above are extracted as candidates. The latter cast shape is selected based on the number of width shifts, but in the latter case, it is selected because the cast of steel type A and the cast of steel type B cannot be connected due to the limitation of the width shift amount in the strand B. It is the former cast shape in which the cast connection is established in both strands even if the number of width transitions is large. In the example shown in FIG. 16, when determining the cast shape of the steel type A, the cast shape of the steel type B to be continuously cast and the connectability between the casts are also taken into consideration. Unlike the slabs assigned to both strands, it is possible to determine the production schedule in which the casting can actually be carried out.

In one embodiment of the present invention, the tentative schedule determination unit 120 tentatively collectively determines a production schedule for continuously casting a plurality of casts of the same steel type corresponding to a plurality of steel types as in the example of FIG. After that, the schedule correction unit 130 corrects the production schedule in consideration of the alternative relationship between the steel grades. Here, when the substitution relationship between the steel grades is considered in the process of sequentially determining the production schedule of the cast corresponding to each steel grade, the steel grade B can be replaced by the steel grade A in the examples shown in FIGS. 15 and 16, for example. In some cases, it is not preferable to cast the slab by the casting of the next steel type B because there is a possibility that the slab which is originally appropriate in terms of manufacturing cost is cast by the casting of the steel type A. For example, when the next cast of steel type B exists, the above situation can be avoided by setting constraint conditions such as excluding the slab of steel type B from the casting target of the alternative steel type in the cast of steel type A. However, in the present embodiment, such a constraint condition is not set by tentatively determining a manufacturing schedule for continuously casting a plurality of casts corresponding to a plurality of steel grades. Can also avoid the above situation.

In the embodiment described above, an example of determining the production schedule of the slab has been described as an example of the cast product, but it is possible to determine the production schedule of other cast products such as bloom and billet in the same manner. Is.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 ... Slab, 10 ... Charge, 11 ... Same steel type cast, 12 ... All casts, 100 ... Manufacturing schedule determination device, 101 ... Slab information file, 102 ... Same steel type cast information file, 104 ... Cast knitting result file, 105 ... Knitting Condition file, 110 ... Data input unit, 120 ... Temporary schedule determination unit, 130 ... Schedule correction unit.

Claims (9)

It is a manufacturing schedule determination device in the continuous casting process that manufactures cast products.
A data input unit in which data including specification information of the cast product including a steel type and information including information about a cast, which is a unit for continuously manufacturing the cast product, is input.
A tentative schedule determination unit that tentatively determines the production schedule of the cast product based on the specification information of the cast product, the information on the cast, and the constraint conditions in the process.
By replacing the first cast product included in the tentatively determined production schedule with a second cast product of another steel type which has a higher production priority and can substitute the steel type of the first cast product. A manufacturing schedule determination device including a schedule correction unit that corrects the manufacturing schedule. The production schedule determination device according to claim 1, wherein the steel type is information that defines at least an allowable range of the component composition of the cast product. The production schedule according to claim 1 or 2, wherein the schedule correction unit executes replacement of the cast products until the number or weight of the second cast products in the cast reaches a predetermined upper limit value. Decision device. The predetermined upper limit is set for the number or weight of the second cast product in the cast, or the ratio of the number or weight of the second cast product to all the cast products in the cast. The manufacturing schedule determination device according to 3. The claim that the schedule correction unit executes the replacement only when the amount of increase in the manufacturing cost of the second casting product due to the replacement of the first casting product with the second casting product is less than the threshold value. The schedule determination device according to any one of claims 1 to 4. The specification information of the cast product includes the expiration date of the next process of the cast product or the urgency of the cast product.
The schedule determination device according to any one of claims 1 to 5, wherein the manufacturing priority is determined based on the context of the passing deadline or the magnitude relationship of the urgency. The cast includes a first cast corresponding to the first steel grade and a second cast corresponding to a second steel grade different from the first steel grade.
The provisional schedule determination unit tentatively collectively determines the production schedule for continuously casting the first cast and the second cast, according to any one of claims 1 to 6. The described scheduling device. It is a manufacturing schedule determination method in the continuous casting process for manufacturing cast products.
A data entry step in which data including specification information of the cast product including the steel grade and information on the cast, which is a unit for continuously manufacturing the cast product, is input.
A tentative schedule determination step for tentatively determining a production schedule of the cast product based on the specification information of the cast product, information on the cast, and process constraints.
By replacing the first cast product included in the tentatively determined production schedule with a second cast product of another steel type which has a higher production priority and can substitute the steel type of the first cast product. A manufacturing schedule determination method including a schedule modification step for modifying the production schedule. A program for determining the manufacturing schedule in the continuous casting process for manufacturing cast products.
A data input unit in which data including specification information of the cast product including a steel type and information including information about a cast, which is a unit for continuously manufacturing the cast product, is input.
A tentative schedule determination unit that tentatively determines the production schedule of the cast product based on the specification information of the cast product, the information on the cast, and the constraint conditions in the process.
By replacing the first cast product included in the tentatively determined production schedule with a second cast product of another steel type which has a higher production priority and can substitute the steel type of the first cast product. A program for operating a computer as a schedule correction unit that corrects the manufacturing schedule.

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