Effects of the ageing of microporous heat-insulating materials on temperature control in steel casting ladies

The shell temperature calculated in the thermal model for the steel casting ladies during circulation was verified by infrared thermography. While the re is a good concurrence for high-alumina-lined steel casting ladies, with maximum variations of 15 Ii emerging, appreciable variations as great as so me 45 Ii were found for basic-lined ladies. The cause of these variations l ies in material changes in the form of shrinkage, carbon deposits and singl e particle growth of the microporous panels utilised for heat insulation. T his results in increased thermal conductivity The variations are reduced to a maximum of 8 K, also for basic-lined ladies, with corrected material dat a. Given the progressive ageing of the insulating panels in the permanent s afety lining, it appears advisable to set a maximum operating time as a fun ction of the conditions prevailing in the steel plant in each case so as to avoid excessive heat losses.