Thermography in the condition monitoring of a refractory lining

This paper is based on a research project carried out during 1997. The objective was to study how an infrared camera can be used for condition monitoring of converters in the steel industry and the conditions under which thermal scanning can be used to estimate wear of a converter's refractory lining. The objects of the study were the chrome converter of Outokumpu Polarit Oy and the LD-converter (BOF) of Rautaruukki Oy Raahe Steel. The condition of the refractory lining of a converter is presently monitored by periodically measuring the wear of the wall with a laser measuring device during shutdowns or between heats. A breakout of the lining is very costly due to resulting interruptions of the manufacturing process. The study was implemented by carrying out a series of tests at both production plants. Wear of the converters was measured using laser measuring equipment. The surface temperature distribution of the converters was measured simultaneously. The results of the laser measurements and thermal scanning were compared. On the basis of the results of this study, it is possible to increase and intensify the use of thermal scanning in condition monitoring of processes of the steel industry or as a process monitoring instrument. Thermal scanning has the significant advantage over other thickness measuring methods that the process need not be interrupted for measuring. The research project will continue in 1999.