Phosphor Thermometry System Under Investigation to Improve Melting and Coating Processes
This new on-line tool is currently being utilized to monitor galvanneal surface temperatures in-process during the galvannealing operation. Project partners include ORNL, the American Iron and Steel Institute, Bailey Engineers, Inc., National Steel Corporation, the University of Tennessee, and Weirton Steel Corporation. Due to system robustness and its remote nature, it is appropriate for precise process control in hot, high electromagnetic interference (EMI) fields, or corrosive environments. It is also particularly well suited for abrasive and chemical reactive exhaust gas environments. Long term applications are thought to include monitoring refractory in furnaces, measuring melt temperatures, measuring roll temperatures on casters or in the hot mill, and monitoring various coating processes.
After the phosphor materials is sprayed, the steel sheet then passes through the galvannealing furnace and the optoelectronics measurement head measures the temperature at the exit of the furnace. The fluorescent phosphor material has been demonstrated to attain thermal equilibrium in less than 0.5 seconds and has been successfully removed or overcoated with no residual damage to the steel surface.
Progress and MilestonesThe initial plant demonstration took place in 1996 with the first prototype system providing on-line temperature data with 5¯F accuracy. The Phase II effort was initiated in the summer of 1998 and was aimed at significantly improving robustness and the accuracy of measurement, while reducing instrument size, weight, and ultimate cost. The Phase II demonstration project began in February 1999 and is currently underway.
Future CommercializationWhile the technology is not currently available to the commercial market, as it matures, it is possible that the technique will become available in a very compact size at an affordable price. Alternative implementations might include a fiber optic probe device that will allow immersion measurements to be made with similarly high robustness and accuracy.
Gains from the project will be realized with the application of this technology where temperature measurement is important to the economics of a process. Other AISI member companies are working with the team to develop approaches applicable to casting, rolling and other steel-making processes. Other manufacturers, from paper to semiconductors, have approached the team members to inquire about the applicability to their industry. IH