Research On Batch Planning Of Hot-rolled Seamless Steel Tubes With Production Operation Factors

As an important basic industrial product,seamless steel tubes are widely used in various fields of the national economy.The hot-rolled batch planning is the core of seamless steel tube production management.Its main task is to batch the production orders and schedule the production batches.The existing hot-rolled batch planning study mainly considers the factors of process constraints in the production process such as steel grade,external diameter,and wall thickness of the product,and the lack of consideration of relevant factors in production operations such as order delivery,periodic machine maintenance,finished product transportation and so on,which limits the application in actual production management greatly.The paper aims at the hot-rolled batch planning of seamless steel tubes,and further considers the factors of production operation on the basis of the production process factors,explores the characteristics of the problems,and presents the corresponding models and algorithms.The main research contents and innovations are as follows:(1)Considering the order delivery in the production operation factors,an order batch optimization model with the goal of minimizing the difference between the order delivery locations and the delivery dates is established.By analyzing the characteristics of the problem,the similarity rule of the process attribute and the similarity rule of the delivery attribute for the order group batch are proposed.Based on these,the algorithm for solving the order group batch problem is designed.The algorithm first classifies the hot-rolled production orders according to the process attribute rules to form coarse batches;then,according to the delivery attribute rules,the hierarchical batch clustering method is used to further classify the coarse batches to form hot-rolled batches.Numerical experiments show that the algorithm can solve the problem well.(2)Considering the factor of periodical maintenance of hot rolling mills in production operation,the hot-rolled batch scheduling problem of seamless steel tubes is transformed into a single machine scheduling problem with periodic fixed time point machine maintenance and setup times,and a mathematical model is established to minimize the idle and machine adjustment.Based on the feature that the setup time between batches depends on the specifications of steel tubes,a minimum rolling mill setup time rule is proposed,and it is proved to be optimal when the maintenance plan is not considered.In addition,a solving strategy and a cyclic solving architecture are furthermore established based on the rule,and a heuristic algorithm is designed based on the characteristic of the problem,and the effectiveness of the algorithm is verified.(3)For the situation that the periodical machine maintenance plan of the hot rolling mill has flexible time point,the commonalities and differences of the machine maintenance plan of flexible and fixed points are analyzed and their effects on the batch scheduling are also analyzed.The problem is transformed into a single machine scheduling problem with flexible maintenance and sequence-dependent setup costs,and a mathematical model to minimize the machine adjustment time and machine idle time is established.The complexity of the problem is analyzed and a two-phase heuristic algorithm is designed.Firstly,the minimum rolling mill setup time rule is used to get the initial optimal sequence with the smallest machine adjustment time.Secondly the global optimal solution based on the initial optimal sequence is used to get the whole optimal value.The comparison experiments on various scales have shown the effectiveness of the model and algorithm.(4)For the finished product transportation in production operation factors,the collaborative management between hot-rolled batch scheduling and finished product transportation is studied.Due to the particularity of the seamless steel tube production and transportation,the problem is abstracted into an integrated batch scheduling problem with grouped delivery of products and setup times,and its mathematical model is established to minimize production and transport resources idle.The complexity of the problem is proved and the existence condition of the optimal solution is discussed.Then,by analyzing the problem,a fast heuristic algorithm based on rules is designed.Finally,multi-scale experiments are carried out to verify the effectiveness of the model and algorithm.