On the use of inline phase transformation sensors in a hot strip mill: case studies

Dynamic cooling control process on the run-out table (ROT) in a hot strip mill (HSM) is an important step to achieve the hot-rolled steel product quality required by customers. The measurements of strip temperature and the amount of transformed phase on the ROT are complementary to each other for the tracking of the material state of the strip during the cooling process. Infrared pyrometers have been widely used for the measurement of strip temperatures, while commercial systems for inline measurement of steel’s phase transformation only became available in recent years. Since 2015, a Transformation Monitor sensor system using EMSpec Technology has been deployed on the ROT of the HSM#2 at Tata Steel in the Netherlands for inline measurement of phase transformation. This paper presents use case studies of the Transformation Monitor. It will demonstrate the advantages of in-situ real time measurement of phase transformation, not only to reveal the internal microstructure of steel strips but also to measure the evolution of transformation–time trajectory on the run-out cooling table, as a complimentary measurement to pyrometer-based surface temperature measurement.