Simulation of air gap formation in slab continuous casting mould

Abstract

A coupled model for describing the air gap formation in a continuous casting mould was developed. In the model, the evolution of the shell and mould temperatures and the gap between them were predicted by a two-dimensional transient thermomechanical coupled finite element model, and the formation of the air gap was described by an interfacial heat transfer model. Based on these, the basic formation characteristics of the air gap in a slab mould during casting of peritectic steel and the influences of varying the casting conditions, such as casting speed, mould taper, molten steel superheat and mould flux solidification temperature on the air gap formation, were described. The results show that the air gap in the mould first forms in the shell corner and mainly concentrates in the regions of 0–20 mm and 0–10 mm from the wide and narrow face corners respectively under typical continuous casting conditions of peritectic steel. The air gap on the shell wide face grows continuously and increases in the low part of the mould, where it mainly forms in the range of 160–450 mm below the meniscus on the shell narrow face. Increasing casting speed reduces the air gap. Increasing mould taper promotes air gap formation on shell wide face but reduces it slightly on the narrow face. Higher steel pouring and mould flux solidifying temperatures result in a wider air gap formation on both the wide and narrow faces.