Study On Logistics Balancing Plans For Hot Rolling, Acid Rolling And Annealing

In large iron and steel enterprises, multi-process and multi-unit is a universal phenomenon, and different products have different process routes, which makes it very difficult to develop production plans which can make full and rational use of the production capacity of each unit, and satisfy the requirement. The plan of logistics balance is to develop rolling capacity allocation plan and to determine the processing sequence of the contracts on each machine. In this thesis, based on the processes of making logistics balance plan and daily production plan, the logistics balancing problems between hot rolling and acid rolling, acid rolling and annealing, annealing and its follow-up process and among multi-processes are respectively proposed by comprehensively considering the contract management, capacity planning, operational plans of production and inventory management in production management business.The main contents of this thesis are as follows:(1) For the problem of logistics balancing between hot rolling and cold rolling, considering the characteristics of the limit specifications and the convergence of different steel grades, a linear mathematical model of the logistics balancing plan between hot rolling and acid rolling is formulated and solved by the optimization software. Then the analysis of the impact of the constraints of slab baked temperature, number of thin volume and the surface quality on logistics balancing, and the treatment of the experimental results on these constraints are given.(2) For the problem of logistics balancing between acid rolling and annealing, by considering the characteristics of minimizing cross-logistics in the process of acid rolling, a linear mathematical model of the balancing plan between acid rolling and annealing is formulated and then solved by the optimization software. Finally, the analysis of the phenomenon in the experimental results to minimize cross-logistics is given. (3) For the problem of logistics balancing between annealing and its follow-up process, by considering the characteristics of batching orders in annealing, a linear mathematical model of the balancing plan between annealing and its follow-up process is formulated and solved by the optimization software. Finally based on the analysis of the experimental results on a set of data, it proves that the result of the model has optimized the process of transition in annealing temperature.(4) For the problem of logistics balancing among hot rolling, cold rolling, annealing and its follow-up process, by considering the characteristics of every process and the convergence of them, a mathematical model of the multi-process logistics balancing plan is formulated. Then a differential evolution algorithm is proposed to solve the problem near optimally. The experimental results can prove efficiency of the proposed differential evolution algorithm.(5) Based on lots of investigation and research, taking a large domestic steel company as background, a decision support system for balance planning in multi-process is designed and developed to satisfy the practical requirements,. The system realizes the whole flow process from the data management to the logistics balancing planning, and helps planners to quickly get better results of production plan.