Plate mill metallurgical quality improvement and process control using off-line simulation and digitalization

The plate mill is the largest and most flexible metallurgical instrument available in the hot rolling of steel. Production performance has traditionally focussed on the accuracy of the final product dimensions. In the last decade, steel producers have placed a greater priority on delivering repeatable and consistent production to achieve final structure property relationships whilst simultaneously minimising environmental impacts and processing costs. This requires the original equipment manufacturer to improve the integrated model based control systems to deliver tight tolerances across all process indicators with an emphasis on delivering exacting through process performance. The production of steel pipe with superior low temperature toughness is one example where through process parameters must successfully combine to deliver the target product. An appreciation of the characteristics of the specific rolling mill in conjunction with the key microstructure and operational parameters is required. These metallurgical and process factors in combination with production trials supported by Primetals Technologies Ltd will be described. Following hot rolling, the use of in-line cooling is proven for high strength steel plates. State of the art cooling technology offers an excellent modernisation package and great flexibility in increasing the product portfolio for a steel producer. Recent progress includes the development of a digital twin to simulate the complete cooling process and predict the final structure property relationships. Added functionality for a standalone system allows the steel producer to consider the results from physical metallography to calibrate the models to specific product groups. Results from a first generation digital twin are described and areas for future development are identified.