Investigation of mould thermal behaviour by means of mould instrumentation

The thermal behaviour of the continuous casting mould has a critical influence on strand surface quality, casting productivity and operating safety. voestalpine Stahl GmbH has long been interested in the field of research into mould behaviour, and began with the investigation of heat flux in 1995, and then of thermal variability in 1999. Since 2000, an online mould thermal monitoring system for heat flux density, thermal variability and friction has been installed. The heat flow density in the mould is determined by measuring the inflow and outflow temperatures and the throughflow volume of the primary cooling water. Temperature as measured by a thermocouple based breakout detection system in the mould copper plate is used to investigate the thermal variability. These online measured values have been employed to examine the influence of casting parameters, steel analysis and casting powder on the heat flux and thermal variability, and the relationship between these variables and cracking. The knowledge gained through these wide ranging plant based investigations has been used as a major tool in the diagnosis of problems ( such as breakout and sticking), for optimisation of the process, particularly in the field of casting powders, and for control of slab quality. In particular, this knowledge has been incorporated into online mould thermal monitoring.