Three-dimensional mathematical modeling of the thin slab continuous casting process

A three dimensional mathematical model has been developed to compute the thermomechanical state in the casting mold of thin slab continuous casters. The mold consists of two broad side walls and two narrow side walls all of which are water cooled. The upper portion of the broad side walls extend apart from each other so that a funnel-shaped chamber is defined. This unique funnel-shaped region allows the nozzle to be submerged into the liquid metal. The chamber converges with distance down the mold, reducing to the shape of the casting at the mold exit. The mold allows the thickness of the continuously cast slab to be less than 60 mm, compared with 150 to 350 mm in conventional continuous slab casting.;Thermal analysis showed the highest mold temperatures along the edge of the funnel region to be just below the meniscus resulting from convergent heat flow which is inherent in the mold design. Elasto-plastic-creep analysis of the mold wall in service determined localized inelastic strains up to 1.3 percent in a region below the meniscus along the funnel edge. The plastic deformation is a result of the high thermal stresses induced by geometric restraint of the mold, coupled with locally high temperatures. Thermal fatigue surface cracks result from the thermal cycling. The computed locations of mold surface cracking, mold deformation and time to failure compared favorably with results from an operating slab caster. Modifying the mold support system in an effort to reduce the restraint to thermal expansion minimized the amount of calculated inelastic deformation.