Annealing PROCESS Control

Many steel wire mills organize production in similar steps: reheating of steel billets is followed by wire shaping in a set of sequential mill stands, starting with roughing mill stands, followed by intermediate mill stands, and various finishing mill stands depending on the target products.

In this example, one product was high-quality steel wire used in car manufacturing, requiring a very demanding and well-controlled annealing process. Material throughput is high. The speed of material in the process changes from a few meters per minute in the roughing mill to more than several hundred meters per minute at finishing sections as material thickness decreases. Given this high speed and throughput, it was of paramount importance to provide the correct material type, dimensions, and temperature just before it enters the annealing process.

This was achieved by assigning temperature readings from various places in the mill to the material's particular longitudinal position, tracking all material in the process, and ensuring a continuous, just-in-time supply to the annealing process using values acquired in previous process steps, combined with information from the ERP.