Stirring plug monitoring system for improvement of plug availability and stirring performance (PLUGWATCH): final report

The aim of this research project was the development and installation of online monitoring systems for stirring plugs in steel ladles in order to determine and predict their availability and performance for stirring processes. Temperature measurement techniques were developed and adapted to the severe conditions in steel plants, especially regarding VOD treatments. Discontinuous measurement of stirring plug temperature was realized and performed for numerous heats using thermocouples and data loggers. Wireless data transmission was not possible due to high temperatures above 350 to 400 °C and low signals. Numerical simulations of temperature distribution in stirring plugs by Finite Elements Method were performed, validated with measured data and used to calculate the effect of reduced flow rates and wear conditions. That information was used to setup models and software for determination of plug performance. The investigations on material properties and simulation of thermo physical chemical evolution in use revealed that the material thermal properties is the key factor to work with the aim to target the improvement of plug performances in terms of wear rate. Software tools were developed for the management of process data and the new temperature information in the stirring plug. Process data, mainly stirring gas flow rate and pressure, form the basis for determination of stirring plug availability and performance. The information and data gained during the project is actually used in the steelworks to further optimize plug operation, although some tasks were very challenging and continuous online application of the monitoring systems during production in the steelworks was not yet possible.