A hot rolled coil purchasing and slitting method for improving material utilization

Abstract

A method for purchasing and slicing hot-rolled coils to improve material utilization includes the following steps: S1: establishing a valid data field database based on hot-rolled coil finished product warehouse data from upstream suppliers and local pending contract data; S2: determining a hot-rolled coil purchasing and slicing plan based on quantitative analysis based on the valid data field database. The method for purchasing and slicing hot-rolled coils to improve material utilization of the present invention first groups the hot-rolled coils and contracts and constructs matching rules, then establishes a mathematical model to quantitatively describe the problem, and finally uses a heuristic / relaxation approach and a traversal search method to obtain an optimized hot-rolled coil purchasing and slicing plan. It has greater adaptability and robustness to the dynamic and changing ordering demands in actual production, and is of great significance to steel companies in improving material utilization, reducing resource waste, and achieving green production.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical automation, and in particular relates to a hot-rolled coil purchasing and slitting method for improving material utilization. Background Art

[0002] Hot-rolled coils offer excellent properties such as high strength, good toughness, ease of fabrication, and excellent weldability, making them widely used in manufacturing industries such as cold-rolled substrates, ships, automobiles, bridges, construction, machinery, oil pipelines, and pressure vessels. The ironmaking, steelmaking, continuous casting, and hot rolling processes required to produce hot-rolled coils require large equipment, high startup and operating costs, and demanding high levels of processing technology and continuity. Some steel companies lack these high-cost upstream production processes and, based on the volume of cold-rolled contracts, must purchase these high-value-added products directly from suppliers' finished product warehouses for further processing.

[0003] Steel mills' demand for hot-rolled coil (HRC) products is becoming increasingly diversified and smaller in batches. This, coupled with the slittable nature of HRC, complicates the design of sourcing and slitting solutions. Currently, most steel companies rely on manual experience to procure HRC. However, manual decision-making is inefficient and unable to cope with increasingly complex product demands. This leads to irrational sourcing and slitting, further exacerbating issues such as low material utilization and contract delays. To alleviate the cost pressures associated with these issues, designing a rational sourcing and slitting approach to improve material utilization, reduce resource waste, and achieve green production has become a technical challenge plaguing steel companies.

[0004] The invention application with application number CN201510367888.7 discloses "an online energy distribution control method for improving the energy utilization rate of steel". First, the historical data of steel production is obtained, and a mathematical model is established to describe the distribution process of the energy medium input of each process. Secondly, the distribution plan of the energy medium input of each process in each time period is determined. Finally, the staff controls the PC end of the energy center to distribute the energy medium to each production process according to the time period to complete the production task; taking into account the real-time changes in production status caused by factors such as the addition of emergency orders, the operating status of equipment, and the differences in the operating levels of workers, as well as the characteristics of primary energy consumption and secondary energy generation in production, the real-time changes in the production environment are closely tracked to achieve efficient energy utilization, improve energy utilization, and reduce energy consumption.

[0005] The invention application with application number: CN201510824047.4 discloses "a steelmaking batching and scheduling method for full-process production". By characterizing the diverse specification attributes of products, the batch production attributes of equipment, and the adaptability between products and equipment, a model is established to quantitatively describe the batching decision-making problem of products in the steelmaking and continuous casting processes. From the perspective of production capacity balance between parallel equipment in the same process and logistics connection between upstream and downstream processes, the distribution and sorting of batches in the continuous casting equipment and time dimensions are modeled, and the batching plan and production scheduling plan are integrated and issued to each production and manufacturing unit in the steelmaking stage to achieve balanced and punctual distribution of steel material flow in the full-process process equipment and time dimensions; improve product quality, increase yield rate, resource utilization, and equipment operating efficiency, achieve load balancing on parallel equipment and smooth material connection between serial equipment, and reduce material flow traffic congestion, downstream equipment waiting time and inventory.

[0006] The invention application with application number CN201810735372.7 discloses "an optimization scheduling method for a steel smelting process". By determining the scheduling model and optimization target of steel smelting in the production process, and proposing an optimization scheduling method based on complete local search with front-end omission, the target is optimized; wherein, the scheduling model is established according to the number of processing operations that each product must undergo and the processing time of the corresponding operations, and the optimization target is determined to minimize the maximum completion time. Summary of the Invention

[0007] To solve the above problems, the present invention provides a method for purchasing and slitting hot-rolled coils to improve material utilization. The technical solution is as follows:

[0008] A method for purchasing and slitting hot-rolled coils for improving material utilization, characterized by comprising the following steps:

[0009] S1: Based on the hot-rolled coil finished product warehouse data from upstream suppliers and the local contract data to be completed, a valid data field database is established;

[0010] S2: Determine the hot rolled coil procurement and slitting plan based on quantitative analysis according to the valid data field database.

[0011] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that it specifically comprises the following steps:

[0012] SS1: Based on step S1, valid data fields are generated for grouping and matching hot-rolled coils with contracts, as well as valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues;

[0013] SS2: Grouping hot-rolled coils and contracts based on corresponding valid data fields. Matching hot-rolled coils and contracts within each group based on corresponding valid data fields and predefined matching rules is completed to form groups of contracts and their matching hot-rolled coils.

[0014] SS3: For each contract and its matching hot-rolled coils, a quantitative objective function is constructed to minimize the total excess material of the hot-rolled coils. Constraints are established based on the valid data fields used to quantitatively describe the hot-rolled coil procurement and slicing problem. Based on this, a mathematical model for this quantitative description is established.

[0015] SS4: Based on the mathematical model, determine the hot rolled coil purchasing and slitting plan described in step S2.

[0016] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0017] The “valid data fields for grouping and matching hot-rolled coils with contracts, and valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues” include:

[0018] Hot rolled coil number, hot rolled coil width, hot rolled coil thickness, hot rolled coil weight, hot rolled coil status, hot rolled coil storage location, hot rolled coil tapping mark, contract number, contract tapping mark, rated rolling thickness, hot rolled coil width upper limit, hot rolled coil width lower limit, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

[0019] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0020] The "valid data fields for quantitatively describing hot rolled coil procurement and slitting issues" include:

[0021] Hot rolled coil weight, contract target order quantity, contract order quantity upper limit, contract order quantity lower limit, hot rolled coil target unit weight, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

[0022] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0023] The "set matching rules" include:

[0024] Static fixed rules used to determine whether the basic attributes of hot-rolled coils match those of the contract.

[0025] as well as

[0026] Dynamic learning rules for determining whether the material properties of hot-rolled coils match the contract.

[0027] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0028] The aforementioned "establishing corresponding constraints based on valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues" specifically includes constraints on five dimensions: matching rules, hot-rolled coil weight, total contract purchase weight, order weight, and hot-rolled coil procurement.

[0029] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0030] The “determining the hot rolled coil purchasing and slitting plan described in step S2” is specifically:

[0031] First, determine the feasible options for contracts and their matching hot rolled coils,

[0032] Secondly, the feasible solutions are optimized so that the final solution is close to the optimal solution.

[0033] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0034] After the hot-rolled coils and contracts are grouped according to step SS2, the compatibility of the grouped contracts and hot-rolled coils is tested according to the established matching rules; step SS3 outputs a qualified output plan for each group of contracts and their matching hot-rolled coils.

[0035] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0036] The static fixed rules include: width matching, thickness matching and weight matching.

[0037] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0038] The dynamic learning rules are formed based on the summary of process requirements and accumulated management experience, through the combination of set logical judgment words and set material property keywords, and the establishment of flexible configuration.

[0039] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0040] The feasible solution is established by:

[0041] First, based on the number of contracts in the group and the number of hot-rolled coils that can be matched, an initial matching plan for contracts and hot-rolled coils is determined according to the set weight constraints.

[0042] Secondly, a feasible hot rolled coil matching and slitting scheme is obtained by adjusting the order weight.

[0043] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0044] The initial matching solution is determined by relaxing the mathematical model described in step SS3.

[0045] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0046] The aforementioned "optimization of feasible solutions so that the final solution approaches the optimal solution" is accomplished by calling a contract exchange module, a contract filling module, and a hot-rolled coil replacement module based on traversal search.

[0047] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0048] The initial matching scheme is established through the following steps:

[0049] SA1: Initialize matching parameters and auxiliary process parameters;

[0050] SA2: Determine the set of contracts that meet the matching rules for each hot-rolled coil, calculate the sum of the weights of the contracts to be matched in the set, and sort the hot-rolled coils from largest to smallest based on the sum. This sorting generates access nodes for the hot-rolled coils in sequence.

[0051] SA3: For each contract set corresponding to the access node, sort all contracts in the contract set from largest to smallest according to the contract target order weight, and establish a match in descending priority based on the sorting;

[0052] SA4: Determine the segmentation plan for each access node under the hot-rolled coil termination constraint;

[0053] SA5: Repeat steps SA2-SA4 until the weight to be matched for all contracts is less than the target order weight, and obtain the initial matching solution and its corresponding parameter values.

[0054] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0055] The relaxation is accomplished by relaxing decision variables and relaxing constraints.

[0056] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0057] The aforementioned “obtaining a feasible hot-rolled coil matching and slitting solution by adjusting the order weight” is specifically:

[0058] First, traverse all contracts and find the contracts whose matched weight is less than the minimum order quantity requirement; based on this, form a set of contracts to be adjusted;

[0059] Secondly, based on meeting the lower limit of the contract order quantity, the contract matching weight in the contract set is updated; and the contracts are sorted from large to small according to the contract matching weight, and the contract matching access nodes are established accordingly;

[0060] Then, for the contract access node, a set of hot-rolled coils that can be matched with it and whose remaining matching weight is greater than zero is determined; the hot-rolled coils are sorted from small to large according to their remaining matching weight, and a matching priority order of the hot-rolled coils is formed based on this sorting;

[0061] Finally, the hot-rolled coil slitting weight plan is adjusted until the matched weight of all contracts meets the lower limit of the order quantity, and a feasible hot-rolled coil matching and slitting plan is obtained.

[0062] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0063] The aforementioned “accomplished by calling the contract exchange module, contract filling module and hot-rolled coil replacement module based on traversal search” is specifically:

[0064] First, traverse any two different hot-rolled coil combinations as access nodes and exchange the splitting schemes of the two hot-rolled coil contracts under the conditions that the hot-rolled coil weight constraints and matching rules are met;

[0065] Secondly, traverse any two different hot-rolled coil combinations as access nodes, and fill the splitting plan of a contract in one hot-rolled coil into the other hot-rolled coil under the conditions that the hot-rolled coil weight constraint and matching rules are met;

[0066] Finally, based on the supplier's hot-rolled coil finished product warehouse data, the current matched hot-rolled coil and unmatched hot-rolled coil combinations are traversed as access nodes. Under the conditions of meeting the hot-rolled coil weight constraints and matching rules, the unmatched hot-rolled coil is purchased to replace the original hot-rolled coil.

[0067] A method for purchasing and slitting hot-rolled coils to improve material utilization according to the present invention is characterized in that:

[0068] The "grouping of hot rolled coils and contracts based on corresponding valid data fields" in step SS2 is specifically as follows:

[0069] The grouping of hot rolled coils and contracts is done according to steel grade.

[0070] To address the problem of low material utilization caused by irrational hot-rolled coil procurement and slicing in steel companies, the present invention proposes a hot-rolled coil procurement and slicing method that improves material utilization. The method first groups hot-rolled coils and contracts and constructs matching rules. A mathematical model is then established to quantitatively describe the problem. Finally, an optimized hot-rolled coil procurement and slicing plan is obtained using a heuristic / relaxation approach and a traversal search method. This method provides a scientifically accurate procurement and slicing solution for the diverse, small-batch needs of hot-rolled coils in actual production. This method boasts high decision-making efficiency and stability, significantly improving material utilization and reducing procurement and production costs.

[0071] In summary, the present invention provides a hot-rolled coil procurement and slicing method for improving material utilization. This method addresses the current hot-rolled coil procurement problem, characterized by complex product specifications and variable slicing schemes. By organically combining matching rules, mathematical modeling, heuristic methods / relaxation processing, and traversal search, it accurately and efficiently determines hot-rolled coil procurement and slicing schemes. This method makes the present invention more adaptable and robust to the dynamic and changing ordering demands in actual production, and is of great significance to steel companies in improving material utilization, reducing resource waste, and achieving green production. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a schematic diagram of the steps of the present invention;

[0073] Figure 2 for Figure 1 Schematic diagram of further detailed steps;

[0074] Figure 3 Schematic diagram of the steps for determining the initial matching solution in the present invention;

[0075] Figure 4 Schematic diagram of the purchasing and slicing method in an embodiment of the present invention;

[0076] Figure 5 Schematic diagram of the hot-rolled coil and contract matching grouping process in an embodiment of the present invention;

[0077] Figure 6 A schematic diagram of generating an initial matching solution in an embodiment of the present invention;

[0078] Figure 7 Schematic diagram of single adjustment based on the initial matching solution in an embodiment of the present invention;

[0079] Figure 8 Schematic diagram of a contract exchange module in an embodiment of the present invention;

[0080] Figure 9 Schematic diagram of a contract filling module in an embodiment of the present invention;

[0081] Figure 10 Schematic diagram of a hot rolled coil replacement module in an embodiment of the present invention. DETAILED DESCRIPTION

[0082] Hereinafter, a hot-rolled coil purchasing and slitting method for improving material utilization of the present invention will be further described in detail based on the accompanying drawings and specific embodiments.

[0083] A method for purchasing and slitting hot rolled coils to improve material utilization, such as Figure 1 As shown, the following steps are included:

[0084] S1: Based on the hot-rolled coil finished product warehouse data from upstream suppliers and the local contract data to be completed, a valid data field database is established;

[0085] S2: Determine the hot rolled coil procurement and slitting plan based on quantitative analysis according to the valid data field database.

[0086] like Figure 2 As shown, further detailed steps are as follows:

[0087] SS1: Based on step S1, valid data fields are generated for grouping and matching hot-rolled coils with contracts, as well as valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues;

[0088] SS2: Groups hot-rolled coils and contracts based on corresponding valid data fields. Matches hot-rolled coils and contracts within each group based on the corresponding valid data fields and the set matching rules, generating groups of contracts and their matching hot-rolled coils. Specifically, grouping hot-rolled coils and contracts is performed based on steel grade.

[0089] SS3: For each contract and its matching hot-rolled coils, a quantitative objective function is constructed to minimize the total excess material of the hot-rolled coils. Constraints are established based on the valid data fields used to quantitatively describe the hot-rolled coil procurement and slicing problem. Based on this, a mathematical model for this quantitative description is established.

[0090] SS4: Based on the mathematical model, determine the hot rolled coil purchasing and slitting plan described in step S2.

[0091] in,

[0092] The “valid data fields for grouping and matching hot-rolled coils with contracts, and valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues” include:

[0093] Hot rolled coil number, hot rolled coil width, hot rolled coil thickness, hot rolled coil weight, hot rolled coil status, hot rolled coil storage location, hot rolled coil tapping mark, contract number, contract tapping mark, rated rolling thickness, hot rolled coil width upper limit, hot rolled coil width lower limit, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

[0094] in,

[0095] The "valid data fields for quantitatively describing hot rolled coil procurement and slitting issues" include:

[0096] Hot rolled coil weight, contract target order quantity, contract order quantity upper limit, contract order quantity lower limit, hot rolled coil target unit weight, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

[0097] in,

[0098] The "set matching rules" include:

[0099] Static fixed rules for determining whether the basic attributes of the hot-rolled coil match the contract, and dynamic learning rules for determining whether the material characteristics of the hot-rolled coil match the contract;

[0100] The static fixed rules include: width matching, thickness matching and weight matching;

[0101] The dynamic learning rules are formed based on the summary of process requirements and accumulated management experience, through the combination of set logical judgment words and set material property keywords, and the establishment of flexible configuration.

[0102] in,

[0103] The aforementioned "establishing corresponding constraints based on valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues" specifically includes constraints on five dimensions: matching rules, hot-rolled coil weight, total contract purchase weight, order weight, and hot-rolled coil procurement.

[0104] in,

[0105] After the hot-rolled coils and contracts are grouped according to step SS2, the compatibility of the grouped contracts and hot-rolled coils is tested according to the established matching rules; step SS3 outputs a qualified output plan for each group of contracts and their matching hot-rolled coils.

[0106] in,

[0107] The “determining the hot rolled coil purchasing and slitting plan described in step S2” is specifically:

[0108] First, determine the feasible options for contracts and their matching hot rolled coils,

[0109] Secondly, the feasible solutions are optimized so that the final solution is close to the optimal solution;

[0110] The feasible solution is established by:

[0111] First, based on the number of contracts in the group and the number of hot-rolled coils that can be matched, an initial matching plan for contracts and hot-rolled coils is determined according to the set weight constraints.

[0112] Secondly, a feasible hot rolled coil matching and slitting scheme is obtained by adjusting the order weight.

[0113] The initial matching scheme can be determined by relaxing the mathematical model described in step SS3 (wherein the relaxation is completed by relaxing the decision variables and the constraints); or it can be established by the following steps, referring to Figure 3 :

[0114] SA1: Initialize matching parameters and auxiliary process parameters;

[0115] SA2: Determine the set of contracts that meet the matching rules for each hot-rolled coil, calculate the sum of the weights of the contracts to be matched in the set, and sort the hot-rolled coils from largest to smallest based on the sum. This sorting generates access nodes for the hot-rolled coils in sequence.

[0116] SA3: For each contract set corresponding to the access node, sort all contracts in the contract set from largest to smallest according to the contract target order weight, and establish a match in descending priority based on the sorting;

[0117] SA4: Determine the segmentation plan for each access node under the hot-rolled coil termination constraint;

[0118] SA5: Repeat steps SA2-SA4 until the weight to be matched for all contracts is less than the target order weight, and obtain the initial matching solution and its corresponding parameter values;

[0119] in,

[0120] The aforementioned "optimization of feasible solutions so that the final solution approaches the optimal solution" is accomplished by calling a contract exchange module, a contract filling module, and a hot-rolled coil replacement module based on traversal search.

[0121] in,

[0122] The aforementioned “obtaining a feasible hot-rolled coil matching and slitting solution by adjusting the order weight” is specifically:

[0123] First, traverse all contracts and find the contracts whose matched weight is less than the minimum order quantity requirement; based on this, form a set of contracts to be adjusted;

[0124] Secondly, based on meeting the lower limit of the contract order quantity, the contract matching weight in the contract set is updated; and the contracts are sorted from large to small according to the contract matching weight, and the contract matching access nodes are established accordingly;

[0125] Then, for the contract access node, a set of hot-rolled coils that can be matched with it and whose remaining matching weight is greater than zero is determined; the hot-rolled coils are sorted from small to large according to their remaining matching weight, and a matching priority order of the hot-rolled coils is formed based on this sorting;

[0126] Finally, the hot-rolled coil slitting weight plan is adjusted until the matched weight of all contracts meets the lower limit of the order quantity, and a feasible hot-rolled coil matching and slitting plan is obtained.

[0127] in,

[0128] The aforementioned “accomplished by calling the contract exchange module, contract filling module and hot-rolled coil replacement module based on traversal search” is specifically:

[0129] First, traverse any two different hot-rolled coil combinations as access nodes and exchange the splitting schemes of the two hot-rolled coil contracts under the conditions that the hot-rolled coil weight constraints and matching rules are met;

[0130] Secondly, traverse any two different hot-rolled coil combinations as access nodes, and fill the splitting plan of a contract in one hot-rolled coil into the other hot-rolled coil under the conditions that the hot-rolled coil weight constraint and matching rules are met;

[0131] Finally, based on the supplier's hot-rolled coil finished product warehouse data, the current matched hot-rolled coil and unmatched hot-rolled coil combinations are traversed as access nodes. Under the conditions of meeting the hot-rolled coil weight constraints and matching rules, the unmatched hot-rolled coil is purchased to replace the original hot-rolled coil.

[0132] Working process, principle and implementation example

[0133] The sorting principle and process are as follows:

[0134] The following steps are involved:

[0135] S1: Hot rolled coil and contract data processing, including the following three steps:

[0136] S1.1: Export the hot rolled coil finished product warehouse data provided by upstream suppliers;

[0137] S1.2: Export local pending contract data;

[0138] S1.3: Filter valid data fields and integrate them into a new data table, which is stored in the local system platform. This data table serves the subsequent hot-rolled coil procurement and slicing decisions;

[0139] S2: Grouping hot-rolled coils and contracts and building matching rules, including the following four steps:

[0140] S2.1: Contracts and HRCs are grouped by steel grade. There is no matching relationship between contracts and HRCs between groups.

[0141] S2.2: Construct matching rules for contracts and hot-rolled coils within the group, including static fixed rules and dynamic learning rules:

[0142] S2.2.1: Static fixed rules determine whether the basic attributes of the hot-rolled coil match the contract, including width, thickness, weight, etc.

[0143] S2.2.2: Dynamic learning rules determine whether the material properties of the hot-rolled coil match the contract. Material properties include specifications, surface, performance process, management, and composition.

[0144] S2.3: Based on the established matching rules, perform rule detection on the compatibility of contracts and hot-rolled coils within the group;

[0145] S2.4: Contracts that do not meet the matching rules will be eliminated and transferred to other suppliers for further procurement;

[0146] S3: For each contract and its matching hot-rolled coils, a mathematical model is established to quantitatively describe the hot-rolled coil procurement and slicing problem. This mainly includes the following three steps:

[0147] S3.1: Decision variables for purchasing and slicing, including which hot-rolled coils to purchase and how to slicing the hot-rolled coils to meet contract order quantity requirements;

[0148] S3.2: Quantitatively describe the matching objective, i.e., minimizing procurement costs: If the purchased hot-rolled coils significantly exceed the contract requirements, this will result in increased excess material and inventory, resulting in higher procurement costs. If the purchased hot-rolled coils just meet the contract requirements, the procurement plan is optimal. If the purchased hot-rolled coils do not meet the contract requirements, the contract will be delayed, making the procurement plan unacceptable. Therefore, the goal of minimizing procurement costs can be transformed into: minimizing the total excess hot-rolled coils while meeting the contract requirements.

[0149] S3.3: Quantitatively describe the matching and splitting constraints of hot rolled coils with contracts;

[0150] Matching rule constraints: Contracts and hot-rolled coils within a group are not completely matched. Therefore, when the contract and hot-rolled coil do not meet the matching rule, the cut weight value must be 0.

[0151] Hot rolled coil weight constraint: The total contract weight matching the hot rolled coil cannot exceed the weight of the hot rolled coil;

[0152] Contract purchase total weight constraint: The total weight of hot-rolled coils allocated to the contract must be within the upper and lower limits of the contract order quantity to avoid stockouts or surplus material.

[0153] Order weight constraint: The order weight should be between the lower and upper limits of hot-rolled coil weight.

[0154] Hot-rolled coil purchase constraint: If the contract weight matched to the hot-rolled coil is greater than zero, the hot-rolled coil is purchased; otherwise, it is not purchased.

[0155] S4: For each contract and its matching hot rolled coils, an initial matching solution is calculated using a heuristic method. The heuristic method includes the following five steps:

[0156] S4.1: Parameter initialization: The contract weight to be matched is the target order quantity of the contract, the remaining matching weight of the hot rolled coil is the hot rolled coil weight, and the matching weight of the hot rolled coil and the contract is set to zero;

[0157] S4.2: Hot rolled coil matching priority ranking: Sort the hot rolled coils by their corresponding matching contracts from largest to smallest total weight, with the hot rolled coil ranked first being prioritized for matching;

[0158] S4.3: Contract matching priority ranking: Sort by contract target weight from largest to smallest, with the hot rolled coil ranked first being given priority for matching;

[0159] S4.4: Design hot rolled coil slitting plan: For the selected hot rolled coil, match the contract with it in turn and design the slitting plan according to the target unit weight of the contract;

[0160] S4.5: Repeat steps S4.2-S4.4 until the weight to be matched for all contracts is less than the target order weight requirement, and an initial matching solution is obtained;

[0161] The above heuristic method is used to calculate the initial matching solution, which can also be replaced by relaxing the original mathematical model. Specifically, first, relax the decision variables and reset the target order quantity of contract i to a constant. The decision variables only retain the procurement decision variable and the number of order quantities. Secondly, relax the constraints, that is, remove the lower limit constraint of the contract order quantity.

[0162] S5: Neither the initial matching solution obtained by the heuristic method nor the relaxed matching solution can necessarily guarantee that all contracts meet the minimum order quantity requirement. The present invention obtains a feasible hot-rolled coil matching and slicing solution by adjusting the order weight, which includes the following six steps:

[0163] S5.1: Find all contracts that do not meet the minimum order quantity requirement and classify them as pending contracts;

[0164] S5.2: Update the contract weight to be matched based on meeting the lower limit of the contract order quantity;

[0165] S5.3: Sort the matching priorities by contract weight from largest to smallest;

[0166] S5.4: Prioritize the hot rolled coils from smallest to largest according to the remaining matching weight;

[0167] S5.5: Adjust the order weight and hot rolled coil slitting plan until the contract matching weight meets the minimum order quantity requirement;

[0168] S5.6: Repeat steps S5.3-S5.5 until the matched weights of all contracts meet the minimum order quantity requirement;

[0169] S6: Improve the procurement and segmentation plan based on traversal search, and finally formulate the hot rolled coil procurement plan, which includes the following four modules:

[0170] S6.1: Contract exchange module: Exchanges the splitting schemes of contracts between two different hot rolled coils, subject to the hot rolled coil weight constraints and matching rules;

[0171] S6.2: Contract filling module: fills the contract slicing plan of one hot rolled coil into another hot rolled coil under the conditions of satisfying the hot rolled coil weight constraint and matching rules;

[0172] S6.3: Hot rolled coil replacement module: Purchase new hot rolled coils to replace the original hot rolled coils under the conditions that the hot rolled coil weight constraints and matching rules are met;

[0173] S6.4: Plan distribution module: Distribute the hot-rolled coil procurement and slitting plan to the procurement department to complete accurate hot-rolled coil procurement decisions.

[0174] Example

[0175] This implementation requires the following hardware: at least one PC; at least one optical or electrical cable interface; and at least one router. These devices form a small local area network (LAN) connected to the company's ERP system (ERP refers to an enterprise resource planning system that provides functions such as accounting, financial management, production control, logistics management, procurement management, distribution management, inventory control, and human resources management). Install the Microsoft SQL Server database system on the PC and set the server address, server port, database name, username, and password for the hardware system.

[0176] A method for purchasing and slitting hot rolled coils to improve material utilization, such as Figure 4 As shown, the following steps are included:

[0177] S1: Hot rolled coil and contract data processing

[0178] S1.1 Export the hot rolled coil finished product warehouse data provided by the upstream supplier to the local computer;

[0179] The hot rolled coil information fields include: hot rolled coil number, cutting time, hot rolled coil width, hot rolled coil thickness, hot rolled coil weight, hot rolled coil status, hot rolled coil storage location, material group, and tapping mark;

[0180] S1.2 Export local pending contract data;

[0181] Contract information fields include: contract number, backlog (unfinished process) number, tapping mark, contract status, contract nature, contract target order quantity, contract order quantity upper limit, contract order quantity lower limit, finished product weight upper limit, finished product weight lower limit, factory delivery period, user contract period, rated rolling thickness, applied under-quantity, rolled under-quantity, hot-rolled coil width upper limit, hot-rolled coil width lower limit, hot-rolled coil target unit weight, hot-rolled coil unit weight lower limit, hot-rolled coil unit weight upper limit, finished plate / coil width, contract composition table, and purchased-out mark.

[0182] S1.3 Filter valid data fields and integrate them into a new data table, which is then stored in the local system platform;

[0183] The valid data field information for filtering is as follows:

[0184] 1) The data fields used by S2 to group hot-rolled coils and contracts and establish matching relationships include: hot-rolled coil number, hot-rolled coil width, hot-rolled coil thickness, hot-rolled coil weight, hot-rolled coil status, hot-rolled coil storage location, hot-rolled coil tapping mark, contract number, contract tapping mark, rated rolling thickness, hot-rolled coil width upper limit, hot-rolled coil width lower limit, hot-rolled coil unit weight lower limit, and hot-rolled coil unit weight upper limit;

[0185] 2) The data fields used in S3 to quantitatively describe the hot-rolled coil procurement and slicing issues include: hot-rolled coil weight, contract target order quantity, contract order quantity upper limit, contract order quantity lower limit, hot-rolled coil target unit weight, hot-rolled coil unit weight lower limit, and hot-rolled coil unit weight upper limit.

[0186] S2: Grouping hot-rolled coils and contracts and building matching rules

[0187] S2.1 Group contracts and hot-rolled coils by steel grade. Based on production process knowledge, there's no matching relationship between contracts and hot-rolled coils of different steel grades. Therefore, to reduce the scale of procurement issues, contracts and hot-rolled coils are first grouped by steel grade. Specifically, hot-rolled coils with the same tapping mark as the contract or with a preferred steel grade are grouped together. If there's no matching relationship between contracts and hot-rolled coils within a group, subsequent procurement and segmentation issues will be handled by group.

[0188] S2.2 Establish matching rules for contracts and hot-rolled coils within the group. Due to differences in rolling requirements, material properties, etc., contracts and hot-rolled coils within the group are not completely matched. Therefore, matching rules need to be established for contracts and hot-rolled coils within the group.

[0189] The matching rules proposed in this invention include static fixed rules and dynamic learning rules:

[0190] S2.2.1 Static fixed rules are basic matching criteria. These rules must be met and cannot be changed. They include basic attributes such as width, thickness, and weight. They are as follows:

[0191] 1) When the width of the hot rolled coil is between the upper and lower limits of the hot rolled coil width specified in the contract, the hot rolled coil is said to match the contract width;

[0192] 2) When the thickness of the hot rolled coil meets the rated rolling thickness specified in the contract, the hot rolled coil is said to match the contract thickness;

[0193] 3) When the weight of the hot-rolled coil is not less than the lower limit of the unit weight of the hot-rolled coil specified in the contract, the hot-rolled coil is said to match the contract weight. Since the hot-rolled coil can be cut, this criterion does not require the weight of the hot-rolled coil to be between the lower limit and the upper limit of the order quantity specified in the contract.

[0194] S2.2.2 Dynamic learning rules are a type of reinforcement rule. These rules are managed by an independent module. Business personnel dynamically generate, maintain, modify, or delete matching rules based on production needs and management experience. The granularity of the reinforcement rules must be reasonably set to avoid useless rule constraints caused by being too coarse or zero matching hot-rolled coil sets caused by being too granular. This module implements flexible rule configuration by reading logical judgment words and material property keywords in the rules:

[0195] 1) Logical judgment words include "greater than", "equal to", "less than", "and", "or", "not", "belong to", and "do not belong to";

[0196] 2) Key words for material properties include: specification properties such as steel grade, length, width, thickness, weight, etc.; surface properties such as sorting grade, coating type, oiling, etc.; performance and process properties such as yield strength, tensile strength, hardness, elongation, etc.; management properties such as material status, contract status, factory storage area, finished product marking, etc.; composition properties such as elements such as C, AL, MN, P, S, etc.

[0197] 3) According to existing embodiments, a typical dynamic learning matching rule based on management characteristics is:

[0198] 4) IF(hot rolled coil information.factory type and warehouse area∈{B,Q}&&(contract information.contract status>=33&&contract information.contract status<=49))

[0199] 5)return TRUE;

[0200] 6)ELSE

[0201] 7)return FALSE;

[0202] The physical meaning of the above rule is that if the hot-rolled coil storage area belongs to B or Q and the contract status is between 33 and 49, the hot-rolled coil matches the contract status; otherwise, it does not match. Obviously, based on actual production and logistics plans, business personnel can dynamically maintain this matching rule, for example, setting the contract status between 20 and 30, thereby reducing production costs and improving delivery efficiency. This example illustrates the flexibility and value of dynamic learning rules. The accumulation of these rules constitutes a valuable knowledge asset for the company.

[0203] S2.3 performs a rule check on the compatibility of contracts and hot-rolled coils within the group based on the established matching rules. The test result is given as a Boolean value, with FALSE indicating a match failure and TRUE indicating a match. For example, if the minimum unit weight of the hot-rolled coil required by the contract exceeds the weight of the supplier's hot-rolled coils, resulting in the contract being unable to match any hot-rolled coil in the supplier's finished hot-rolled coil inventory, the output is FALSE.

[0204] S2.4 finally removes the contract that does not meet the matching rules (marked as FALSE) and transfers the contract to other suppliers for further procurement.

[0205] See the above corresponding Figure 5 .

[0206] S3: Build a mathematical model to quantitatively describe the procurement and slitting issues of hot-rolled coils

[0207] For a group of contracts and their matching hot-rolled coils: let M be the total number of contracts, i be the contract index, i=1,...,M; N be the total number of hot-rolled coils that can be matched by the group of contracts, j be the hot-rolled coil index, j=1,...,N; since not every contract and hot-rolled coil in the group is completely matched, let the matching parameter a ij is a 0 / 1 variable. If a ij =1, contract i matches hot rolled coil j, otherwise they do not match. For matching rules, refer to S2.

[0208] S3.1 Decision variables for purchasing and segmentation

[0209] o j is the purchasing decision variable. If the jth hot-rolled coil is purchased, then o j =1, otherwise o j =0; let x ijis the cutting decision variable, which represents the weight of the j-th hot-rolled coil cut for contract i; n ij The number of order weights for the jth hot-rolled coil under the i-th contract, which is a non-negative integer.

[0210] S3.2 Quantitative description of objectives

[0211] The goal is to minimize the amount of hot rolled coil surplus material under the premise of meeting the contract requirements. The calculation formula for the amount of hot rolled coil surplus material is shown in formula (1), where w j is the weight of hot rolled coil j: if hot rolled coil j is purchased, that is, o j =1, then the weight of the remaining material of hot-rolled coil j is If you do not purchase hot rolled coil j, that is, o j =0, according to the following constraints (6) and (7), o j =0 can simultaneously ensure That is, the remaining material is 0;

[0212]

[0213] S3.3 Quantitative description of the matching and segmentation constraints of hot rolled coils and contracts

[0214] (1) Matching rule constraint: When contract i and hot-rolled coil j are matched, that is, a ij =1, the cut weight x ij The value is greater than or equal to zero. Otherwise, if contract i and hot rolled coil j cannot match, that is, a ij =0, the cutting weight x ij The value is equal to zero. The constraint is shown in formula (2), where H is a very large number:

[0215] x ij ≤Ha ij , i=1,…,M j=1,…,N--------(2)

[0216] (2) Hot rolled coil weight constraint: the total contract weight matching hot rolled coil j Cannot exceed the weight of hot rolled coil w j , as shown in formula (3):

[0217]

[0218] (3) Contract purchase total weight constraint: Order quantity of contract i At the lower limit of order quantity and order quantity limit As shown in formula (4):

[0219]

[0220] (4) Order weight constraint: The lower and upper limits of the hot-rolled coil weight for contract i are and The number of orders for the jth hot-rolled coil under the i-th contract is n ij Therefore, the weight x of hot rolled coil j allocated to contract i ij Should be In the range, as shown in formula (5):

[0221]

[0222] (5) The hot-rolled coil procurement constraint is defined by equations (6) and (7): If the total contract weight of hot-rolled coil j is matched If it is greater than zero, the hot rolled coil is purchased, i.e. j =1, otherwise no purchase, i.e. o j =0, H in formula (6) is a very large number:

[0223]

[0224]

[0225] S4: Use heuristic / relaxation methods to obtain the initial matching solution

[0226] For the M contracts in the group and their matching N hot-rolled coils, the initial matching scheme S between the contracts and the hot-rolled coils is determined by relaxing the original mathematical model. Specifically, the decision variables are first relaxed and the target order of contract i is reset to a constant Only the purchase decision variable is retained. j and the order quantity n ij Secondly, the constraints are relaxed, that is, the lower limit constraint of the contract order quantity is removed. Then, the initial matching solution obtained by solving the relaxed model may not meet the lower limit requirement of the contract order quantity, that is, it may not be a feasible hot-rolled coil matching and slicing solution.

[0227] The parameter form of the initial matching solution S is (n ij ,x ij ), represents the number of units n cut from the jth hot-rolled coil for contract i ij And total weight x ij , the number of parameters of the initial matching scheme S is M×N. The relaxed mathematical model is as follows:

[0228] S4.1 Initialize matching parameters

[0229] For any hot-rolled coil j and any contract i in the group, the parameters of the matching scheme S are initialized to (n ij =0,x ij =0).

[0230] S4.2 Relaxation decision variables

[0231] Let the target order weight of contract i be a constant, and set it as target order weight Then the decision variables in S3.1 are Therefore, the decision variables only retain the purchase decision variable o j and the order quantity n ij .

[0232] The objective function of the S4.3 relaxation model is:

[0233]

[0234] S4.4 The constraints of the relaxed model are:

[0235] (1) Matching rule constraints:

[0236]

[0237] (2) Hot rolled coil weight constraints:

[0238]

[0239] (3) The total weight constraint of the contract purchase is as follows. In order to improve the efficiency of mathematical programming solution, the lower limit constraint of the contract order quantity is relaxed compared with the original mathematical model.

[0240]

[0241] (4) Hot-rolled coil procurement constraints

[0242]

[0243]

[0244] S4.5 uses a commercial optimization solver to solve the mixed integer programming model above and obtains the initial matching solution S and its corresponding parameters (n ij ,x ij ), where The initial matching solution obtained by solving the relaxation model may not necessarily meet the lower limit of the contract order quantity. Further adjustments are needed to obtain a feasible hot-rolled coil matching and slitting solution.

[0245] The relaxation process mentioned above can also be replaced by a heuristic method, specifically:

[0246] For the M contracts in the group and their N matching hot-rolled coils, the initial matching solution S between the contracts and the hot-rolled coils is determined according to the weight constraint. The parameter form of the initial matching solution S is (n ij ,x ij), represents the number of units n cut from the jth hot-rolled coil for contract i ij And total weight x ij , the number of parameters of the initial matching scheme S is M×N.

[0247] S4.1 Initialize matching parameters: For any hot-rolled coil j and any contract i in the group, the parameters of the matching scheme S are initialized to (n ij =0,x ij = 0). Other auxiliary process parameters are initialized as: contract weight to be matched d i Equal to the contract target order quantity The value range of Hot rolled coil remaining matching weight h j Equal to the weight of hot rolled coil w j ;

[0248] S4.2 Hot rolled coil priority sorting: Find the contract set I that satisfies the matching rules for each hot rolled coil j , calculate the sum of the weights to be matched of the contracts in the set (I j ), and according to sum(I j ) value from large to small to prioritize the hot rolled coils, and select the hot rolled coil j with the highest priority * As the current access node. Specifically, the hot rolled coil priority sorting includes the following three steps:

[0249] S4.2.1 For each hot rolled coil j, find the ij =1) and the weight to be matched is not less than the target order weight Contract Set I j , where the target order weight of contract i is The value range is

[0250] S4.2.2 For each hot rolled coil j, calculate the set I j The sum of the weights to be matched of all contracts in sum(I j ),Right now If the remainder of hot rolled coil j can match the weight h j Less than set I j The target order weight of any contract in the contract is, then let sum(I j )=0;

[0251] S4.2.3 For all hot rolled coils, select sum(I j ) value of the hot rolled coil j * If the values of multiple hot-rolled coils are the largest, the remaining hot-rolled coil with the smallest matching weight j is selected. *Perform matching;

[0252] S4.3 Contract Priority Sorting: Current Hot Rolled Coil Access Node j * The corresponding contract set is I j* , for set I j* All contracts in the contract are re-ordered according to the contract target order i aim The values are sorted from large to small, and the sorted set I j* In , contract i has a higher matching priority than contract i+1;

[0253] S4.4 Design the current hot rolled coil access node j * The segmentation scheme, update the parameters (n ij *,x ij* ) value: take contract i=0 as the initial access node, set I j* The contracts in the order of hot rolled coil j * Matching, hot rolled coil * According to the target order list of contract i, we design the segmentation plan and get (n ij *,x ij* ) and update the contract weight d i =d i -x ij* , update the remaining matching weight h of the hot rolled coil i =h i -x ij* , the hot rolled coil j is terminated when one of the following two conditions is met * Slitting design: ① Hot rolled coil * The remaining matching weight h i Less than set I j* The target order weight of all the contracts to be matched in the set I j* The weight d of all contracts to be matched i Both are less than the target order weight

[0254] S4.5 Repeat steps S4.2-S4.4 until all contracts with matching weight d are i Less than target order weight Get the initial matching solution S and its corresponding parameters (n ij ,x ij ) value.

[0255] S5: Adjust the order weight to obtain a feasible hot rolled coil matching and slitting plan

[0256] The initial matching solution S obtained by S4 is designed based on the target order quantity of the contract for matching and segmentation. Therefore, a large number of contracts can ensure matching weight in the initial matching solution. Meet the minimum order quantity However, there are a small number of contracts that do not meet the minimum order quantity requirement. Therefore, it is necessary to further adjust the order weight to obtain a feasible hot rolled coil matching and cutting scheme S'. Initialize the feasible scheme S' = S, and update the parameters (n ij ,x ij ) value:

[0257] S5.1 Determine the set of contracts to be adjusted I′: The set of contracts to be adjusted I′ is initialized to Traverse all M contracts and calculate the matched weight of contract i according to the initial matching scheme S: If the matched weight of contract i is less than the lower limit of the order quantity, contract i is classified into the set of contracts to be matched I′, that is, I′=I′∪{i}, and the set of contracts to be adjusted is

[0258] S5.2 Update the weight of the contracts to be matched in the set I′ and put the value into the set D′: The contract weight set D′ is initialized to Based on meeting the lower limit of the contract order quantity, the weight of the contracts to be matched in the updated set I′ is The set D′ is updated to D′=D′∪{d i};

[0259] S5.3 Contract matching priority sorting: Sort the contracts in set D′ by their weight to be matched from large to small, and select the contract i with the largest weight to be matched. * Match as the initial access node;

[0260] S5.4 Hot Rolled Coil Matching Priority Sorting: For contract access node i * , find a hot rolled coil set J that can match it and whose remaining matching weight is greater than zero i* , sort the hot-rolled coils from small to large according to the remaining matching weight. The sorted hot-rolled coil index is represented by k. Hot-rolled coil k has a higher matching priority than hot-rolled coil k+1;

[0261] S5.5 Hot rolled coil slitting weight plan adjustment: For set J i* All hot-rolled coils in the contract i are accessed in turn, with hot-rolled coil k=0 as the initial access node. * Match, repeat steps S5.5.1 and S5.5.2 until contract i * The matching weight meets the lower limit of order quantity, and then the contract i * Eliminate from the set I′ and D′, that is, I′=I′-{i *}, D′=D′-{di*}, and update the parameters in the matching scheme S′:

[0262] S5.5.1 If the contract to be matched has a weight d i* and the remaining weight of the hot rolled coil h k Not less than the minimum order weight Then let the hot rolled coil k cut weight Give Contract * , the update scheme S′ parameters are Renewal of Contract * Weight to be matched Update the remaining matching weight of hot rolled coil k

[0263] S5.5.2 If the contract's weight to be matched is d i* Or the remaining weight of the hot rolled coil h k Less than the lower limit of the order weight When the hot rolled coil k is divided into contract i in the initial matching scheme * Weight x i*k When it is greater than zero, the weight of the contract to be matched can be reduced by increasing the split unit weight. The split unit weight in the initial matching plan is the target unit weight. Increased single weight U′ i* Should not exceed the upper limit And the total increase does not exceed the upper limit of the contract order quantity and the weight of the hot rolled coil w k , the update scheme S′ parameter is (n i*k ,x i*k )=(n i*k ,n i*k U′ i* ); When the hot rolled coil k is divided into contract i in the initial matching scheme * Weight x i*k When it is equal to zero, no adjustment is possible and the next matching hot rolled coil is replaced, and k=k+1; if the remaining matching weight of hot rolled coil k is zero, the next matching hot rolled coil is replaced, and k=k+1;

[0264] S5.6 Repeat steps S5.3-S5.5 until the matched weights of all contracts meet the minimum order quantity requirement, i.e. and At the same time, a feasible hot rolled coil matching and slitting scheme S′ is obtained. Figure 6 、 7 ,for Figure 6 Note: Assume that hot rolled coil 1 is the hot rolled coil with the highest priority at present; the contract set I1 matching hot rolled coil 1 = {Contract 1, Contract 2}; because Prioritize contract 1, then contract 2; for Figure 7 Note: Contract 1 does not meet the minimum order quantity requirement. Under the constraint of not exceeding the upper limit of the order weight and the weight of the hot-rolled coil, the single weight Increase to In this case, it is assumed that the remaining matching weight of the hot rolled coil h1 is equal to the matching weight of Contract 1. Then Δ is taken as h1 / 2. After adjusting the unit weight, Contract 1 meets the minimum order limit, and there is no excess material in Hot Rolled Coil 1.

[0265] S6: Improved procurement and segmentation solutions based on traversal search

[0266] Reference Figure 8 、 9 10; Call the contract exchange module, contract filling module and hot rolled coil replacement module based on traversal search to improve the matching and segmentation plan S' in S5, and issue the final hot rolled coil procurement plan B * and segmentation scheme S * Plan B * The parameters are o j Indicates that the number of parameters is N. If the jth hot rolled coil is purchased, then o j =1, otherwise o j =0, procurement plan B * The parameters are initialized to Traversal search improvements mainly include the following five steps:

[0267] S6.1 calls the contract exchange module: traverses any two different hot-rolled coil combinations (j1 and j2) as access nodes, and exchanges the splitting scheme of the two hot-rolled coil contracts (i1 and i2) under the conditions of satisfying the hot-rolled coil weight constraints and matching rules, that is, the exchange scheme S * (n i1,j1 ,x i1,j1 ) and (n i2,j2 ,x i2,j2 ) value;

[0268] S6.2 calls the contract filling module: traverse any two different hot-rolled coil combinations (j1 and j2) as access nodes, and fill the cutting scheme of a certain contract (i) in one hot-rolled coil (j1) into another hot-rolled coil (j2) under the conditions of satisfying the hot-rolled coil weight constraint and matching rules, that is, let the scheme S * (n i,j2 ,x i,j2 )=(n i,j2 ,x i,j2 )+(n i,j1 ,x i,j1 ) and (n i,j1 ,x i,j1 )=(0,0);

[0269] S6.3 calls the hot rolled coil replacement module: Based on the supplier's hot rolled coil finished product warehouse data, traverse the currently matched hot rolled coil and the unmatched hot rolled coil combination (j1 and j2) as access nodes, and purchase the unmatched hot rolled coil (j2) to replace the original hot rolled coil (j1) under the conditions of meeting the hot rolled coil weight constraint and matching rules. That is, for solution S * For any contract i in i,j2 ,x i,j2 )=(n i,j1 ,x i,j1 ) and (n i,j1 ,x i,j1 )=(0,0), this module is suitable for the case where there are many optional hot-rolled coil specifications. It is not applicable if the hot-rolled coil specifications are the same;

[0270] S6.4 Determine Procurement Plan B * : After calling and executing the above adjustment module, the final matching and segmentation solution S is obtained * , based on the segmentation scheme S * , calculate the total matching weight of each hot rolled coil j If its value is greater than 0, then let B * The parameter value o in j =1, thus obtaining the final hot rolled coil procurement plan B * .

[0271] S6.5 Issue the procurement and cutting plan: Hot rolled coil procurement plan B * Send to the purchasing department, split plan S * It is sent to the manufacturing department for subsequent production and final decision-making on accurate hot rolled coil procurement and slitting is made.

[0272] To address the problem of low material utilization caused by irrational hot-rolled coil procurement and slicing in steel companies, the present invention proposes a hot-rolled coil procurement and slicing method that improves material utilization. The method first groups hot-rolled coils and contracts and constructs matching rules. A mathematical model is then established to quantitatively describe the problem. Finally, an optimized hot-rolled coil procurement and slicing plan is obtained using a heuristic / relaxation approach and a traversal search method. This method provides a scientifically accurate procurement and slicing solution for the diverse, small-batch needs of hot-rolled coils in actual production. This method boasts high decision-making efficiency and stability, significantly improving material utilization and reducing procurement and production costs.

[0273] In summary, the present invention provides a hot-rolled coil procurement and slicing method for improving material utilization. This method addresses the current hot-rolled coil procurement problem, characterized by complex product specifications and variable slicing schemes. By organically combining matching rules, mathematical modeling, heuristic methods / relaxation processing, and traversal search, it accurately and efficiently determines hot-rolled coil procurement and slicing schemes. This method makes the present invention more adaptable and robust to the dynamic and changing ordering demands in actual production, and is of great significance to steel companies in improving material utilization, reducing resource waste, and achieving green production.

Claims

1. A method for purchasing and slitting hot rolled coils to improve material utilization, characterized in that The steps include: S1: Based on the hot-rolled coil finished product warehouse data from upstream suppliers and the local contract data to be completed, a valid data field database is established; S2: Determine the hot rolled coil purchasing and slitting plan based on quantitative analysis according to the valid data field database. Specifically, SS1: Based on step S1, valid data fields are generated for grouping and matching hot-rolled coils with contracts, as well as valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues; SS2: Grouping hot-rolled coils and contracts based on corresponding valid data fields. Matching hot-rolled coils and contracts within each group based on corresponding valid data fields and predefined matching rules is completed to form groups of contracts and their matching hot-rolled coils. SS3: For each contract and its matching hot-rolled coils, a quantitative objective function is constructed to minimize the total excess material of the hot-rolled coils. Constraints are established based on the valid data fields used to quantitatively describe the hot-rolled coil procurement and slicing problem. Based on this, a mathematical model for this quantitative description is established. SS4: Based on this mathematical model, determine the hot rolled coil procurement and slitting plan described in step S2, The hot rolled coil purchasing and slitting plan described in the determination step S2 is specifically: First, determine the feasible options for contracts and their matching hot rolled coils, The feasible solution is established by: First, based on the number of contracts in the group and the number of hot-rolled coils that can be matched, an initial matching plan for contracts and hot-rolled coils is determined according to the set weight constraints. Secondly, by adjusting the order weight, a feasible hot rolled coil matching and slitting plan is obtained. The feasible hot rolled coil matching and slitting scheme obtained by adjusting the order weight is specifically as follows: First, traverse all contracts and find the contracts whose matched weight is less than the minimum order quantity requirement; based on this, form a set of contracts to be adjusted; Secondly, based on meeting the lower limit of the contract order quantity, the contract matching weight in the contract set is updated; and the contracts are sorted from large to small according to the contract matching weight, and the contract matching access nodes are established accordingly; Then, for the contract access node, a set of hot-rolled coils that can be matched with it and whose remaining matching weight is greater than zero is determined; the hot-rolled coils are sorted from small to large according to their remaining matching weight, and a matching priority order of the hot-rolled coils is formed based on this sorting; Finally, the hot rolled coil slitting weight plan is adjusted until the matched weight of all contracts meets the lower limit of the order quantity, and a feasible hot rolled coil matching and slitting plan is obtained. Secondly, the feasible solutions are optimized so that the final solution is close to the optimal solution.

2. A method for purchasing and slitting hot-rolled coils to improve material utilization according to claim 1, characterized in that: The "valid data fields for grouping and matching hot-rolled coils with contracts, and valid data fields for quantitatively describing hot-rolled coil procurement and slicing issues" include: Hot rolled coil number, hot rolled coil width, hot rolled coil thickness, hot rolled coil weight, hot rolled coil status, hot rolled coil storage location, hot rolled coil tapping mark, contract number, contract tapping mark, rated rolling thickness, hot rolled coil width upper limit, hot rolled coil width lower limit, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

3. The method for purchasing and slitting hot-rolled coils to improve material utilization according to claim 1, characterized in that: The "valid data fields for quantitatively describing hot rolled coil procurement and slitting issues" include: Hot rolled coil weight, contract target order quantity, contract order quantity upper limit, contract order quantity lower limit, hot rolled coil target unit weight, hot rolled coil unit weight lower limit, hot rolled coil unit weight upper limit.

4. The method for purchasing and slitting hot-rolled coils to improve material utilization according to claim 1, characterized in that: The "set matching rules" include: Static fixed rules used to determine whether the basic attributes of hot-rolled coils match those of the contract. as well as Dynamic learning rules for determining whether the material properties of hot-rolled coils match the contract.

5. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: The aforementioned "establishing corresponding constraints based on valid data fields for quantitatively describing the hot-rolled coil procurement and slicing problem" specifically includes constraints on five dimensions: matching rules, hot-rolled coil weight, total contract purchase weight, order weight, and hot-rolled coil procurement.

6. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: After the hot-rolled coils and contracts are grouped according to step SS2, the compatibility of the grouped contracts and hot-rolled coils is tested according to the established matching rules; step SS3 outputs a qualified output plan for each group of contracts and their matching hot-rolled coils.

7. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 4, characterized in that: The static fixed rules include: width matching, thickness matching and weight matching.

8. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 4, characterized in that: The dynamic learning rules are formed based on the summary of process requirements and accumulated management experience, through the combination of set logical judgment words and set material property keywords, and the establishment of flexible configuration.

9. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: The initial matching solution is determined by relaxing the mathematical model described in step SS3.

10. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: The aforementioned "optimizing feasible solutions so that the final solution approaches the optimal solution" is accomplished by calling a contract exchange module, a contract filling module, and a hot-rolled coil replacement module based on traversal search.

11. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: The initial matching scheme is established through the following steps: SA1: Initialize matching parameters and auxiliary process parameters; SA2: Determine the set of contracts that meet the matching rules for each hot-rolled coil, calculate the sum of the weights of the contracts to be matched in the set, and sort the hot-rolled coils from largest to smallest based on the sum. This sorting generates access nodes for the hot-rolled coils in sequence. SA3: For each contract set corresponding to the access node, sort all contracts in the contract set from largest to smallest according to the contract target order weight, and establish a match in descending priority based on the sorting; SA4: Determine the segmentation plan for each access node under the hot-rolled coil termination constraint; SA5: Repeat steps SA2-SA4 until the weight to be matched for all contracts is less than the target order weight, and obtain the initial matching solution and its corresponding parameter values.

12. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 9, characterized in that: The relaxation is accomplished by relaxing decision variables and relaxing constraints.

13. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 10, characterized in that: The aforementioned "accomplished by calling the contract exchange module, contract filling module and hot-rolled coil replacement module based on traversal search" is specifically: First, traverse any two different hot-rolled coil combinations as access nodes and exchange the splitting schemes of the two hot-rolled coil contracts under the conditions that the hot-rolled coil weight constraints and matching rules are met; Secondly, traverse any two different hot-rolled coil combinations as access nodes, and fill the splitting plan of a contract in one hot-rolled coil into the other hot-rolled coil under the conditions that the hot-rolled coil weight constraint and matching rules are met; Finally, based on the supplier's hot-rolled coil finished product warehouse data, the current matched hot-rolled coil and unmatched hot-rolled coil combinations are traversed as access nodes. Under the conditions of meeting the hot-rolled coil weight constraints and matching rules, the unmatched hot-rolled coil is purchased to replace the original hot-rolled coil.

14. The method for purchasing and slitting hot-rolled coils for improving material utilization according to claim 1, characterized in that: The "grouping of hot rolled coils and contracts based on corresponding valid data fields" described in step SS2 is specifically as follows: The grouping of hot rolled coils and contracts is done according to steel grade.

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