EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

The efficiency of a batch annealing bay is to a large extent dependent on which coils are combined to create the stacks. At Tata Steel IJmuiden a smart stack building algorithm is in use to optimize productivity. However, over the past few years the throughput of the batch annealing bay has become more volatile as more steel was shifted to the hot dip galvanizing lines. Especially when throughput was low this has resulted in a decrease in timely coil delivery as optimization was still done on productivity. To ensure timely delivery of delayed coils this has led to an increasing need for manual intervention in the bay scheduling. To solve this issue the optimization target of the stack building algorithm was modified, incorporating not only bay productivity but also timely coil delivery. By using the new optimization target a smarter balance between efficiency and delivery performance was obtained. This has resulted in a reduction of delayed coils from 27% to 4% of the coil population without noticeable effect on productivity. In addition, the automated response to changing conditions reduced the need for manual intervention in bay scheduling. Before implementation nearly daily intervention was necessary to ensure timely coil delivery. After implementation no manual intervention has been required for a period of 3 consecutive months.