1990 Volume 30 Issue 2 Pages 161-166
The fully automated mill pacing control system in the bar mill at Muroran Works of Nippon Steel Corporation is a control type expert system developed to determine and to control automatically the material discharge pitch from the reheating furnace. The material discharge pitch is a dominating factor affecting productivity and operating efficiency. Until now, it has been difficult to establish a mathematical model for determining the optimal discharge pitch because of the following:
1) complex material flow caused by variations in processing and production capacity, and
2) variations in flow due to differences in material quality and size of the steel bar being produced.
The fully automated discharge system was realized by developing an expert system based on the most suitable inference of productivity in each process of steel bar flow. The production capacity of mill and finishing line is determined from a knowledge base. How the expert system achieves on-line and real-time control and how the mill pacing control is performed are described in this paper. The fully automated mill pacing control expert system for the bar mill at Muroran Works achieved following production improvements:
1) Improvement in rolling tons per hour due to minimization of discharge pitch, and
2) Improvement in production efficiency by avoiding discharge interruption caused by line jam.