ON-LINE FUZZY REGULATOR FOR CONTINUOUS CASTING PROCESS

Nowadays, continuous casting (CC) is used for providing almost one hundred percent of steel world production. The control of quality in CC products cannot be achieved without the knowledge of heat transfer and solidification of cast slabs. The solidifying slab passing through the caster is subjected to variable thermal conditions and mechanical stresses which can cause many serious defects in final structure of slabs. These defects might be eliminated by the optimal control of casting process. This paper describes an algorithm used to obtain time dependant casting parameters for stabilization of the casting process where high productivity is preserved. The presented algorithm can be used in two regimes. The first regime (off-line) can be used to find the control parameters such the casting speed and cooling intensities in the secondary cooling zone in order to get slab surface and core temperatures in specific ranges. The second regime allows the on-line regulation, stabilization of CC process and an immediate reaction to non-standard casting conditions such as a casting speed variation, or a breakdown of nozzle or cooling circuit in the secondary cooling. The algorithm is created as coupling between our original three-dimensional numerical model of temperature field and the regulation algorithm based on the fuzzy logic approach. The simulations indicate a good regulation efficiency and applicability for the real casting process.