Generally, an iron and steel plant produces slabs according to the customer requirements on steel products, such as specification, steel grade, chemical composition, hardness and so on. During the steel production process, first of all, a production schedule is made for steelmaking and continuous casting according to the production order. After slabs are produced, they are subjected to further treatments such as hot-rolling, cold-rolling and so on according to the customer requirements on the products. Finally, finished products are produced to be delivered to the customers. However, the following several reasons cause a low slab utilization, leading to a lot of irrational slab-order matching relationships: 1) In the current iron and steel market, orders tend to require a large variety and a small volume production, which is contradictory to batch production mode of iron and steel industry, for example, a converter or an electric furnace can handle 300 or 250 tons of molten steel in a batch, such that the amount of slabs in accordance with the order may be more than that required by the order; 2) when allocating the open-order slabs to orders, the matching relationship between the open-order slabs and the orders may be sub-optimal due to lack of working experiences and complete information; 3) the generation of unqualified products in post operations may cause that the amount of the products remaining for the order, to which the unqualified products belong, is less than that required by the order. Then, some more slabs need to be allocated to this order.
In prior literatures, most of the domestic and foreign studies on the slab matching problem aim at open-order slabs, which is about the matching of the surplus inventory, while the present invention tries to re-optimize the matching relationship in consideration of the original slab-order matching relationship and the load balance of all equipment units, so as to improve the slab-order matching relationship, decrease the slab cutting loss, reduce the redundant slabs weight of each order, and improve the integrity of an order, thus improving slab utilization, ensuring to deliver an urgent order on time, and improving the customer satisfaction.