Re-matching method of slab-order for improving slab utilization in iron and steel plants

A re-matching method of slab-order for improving slab utilization in iron and steel plants, characterized in that it comprises the steps of:

• Step 1:
• formulating a mathematical model according to information of slabs and orders, so as to quantitatively describe a re-matching problem of slab-order;
• Step 2:
• dividing the slabs and orders into groups;
• and
• Step 3:
• generating a new slab-order matching relationship for each group of slabs and orders by using multiple neighborhoods based tabu search algorithm on the basis of the formulated mathematical model,
• wherein, in Step 1, the performance measures for evaluating the matching relationship between slabs and orders are converted into an objective function, and by constructing objectives and expressing matching constraints, a mathematical model for the re-matching problem is formulated and described as follows:
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• wherein, M denotes set of all assignable orders, N denotes set of all assignable slabs, c1ij denotes cost caused by steel grade difference when an assignable slab i is assigned to an assignable order j;
• wherein c2ij denotes cutting loss cost caused by specification differences in weight, width and length when slab i is assigned to order j;
• wherein, u1 denotes penalty cost caused by the redundant slab weight of the order, ai denotes weight of slab i Ajmax:
• denotes an upper limit of a required slab weight of order j;
• wherein, u2 denotes the penalty cost caused by the under-fulfilled slab weight of Ajmin the order, denotes a lower limit of the required slab weight of order j, UW denotes a maximum value of penalty cost caused by the under-fulfilled slab weight;
• wherein, Rj denotes priority awards related to a due date of order j, the order with a tighter due date should be given a higher priority;
• wherein, Pj denotes the penalty for the unfulfilled order j, Aj denotes the required slab weight of order j, ALj denotes a maximal under-fulfilled slab weight of order j, function v(x) denotes that v(x)=1 when x>0, and v(x)=0 when x<0;
• wherein, Hk denotes a set of the-orders involving the equipment units K, Tk denotes a maximal capacity of the equipment units K.