Infiltration phenomena of molten powder in continuous casting derived from analysis using reynolds equation part 2: Unsteady analysis

Abstract

A new type of model for the powder infiltration in continuous casting of steel is developed. Succeeding the previous report on a steady state analysis, this paper presents an unsteady model that uses Reynolds equation and the equation of the motion of the solidified shell as fundamental equations. The analysis clarifies in details the cyclic movement of a solidified shell during mold oscillation. Mold powder can be infiltrated because the cyclic movement of the shell lags behind the mold oscillation. This provides a period when the mold/cast metal gap opens, during the downward motion of the mold. In this period, molten powder is infiltrated down into the channel. The model also clarifies that the powder infiltration is greatly influenced by two factors; the peak distance between solidified shell and mold wall during the oscillation, and the phase shift of the movement of solidified shell from the mold oscillation. Furthermore, the tendency of the powder consumption to decrease with increasing the powder viscosity can be easily understood through the mechanism of the powder infiltration derived from the analysis. Those results indicate that the model essentially reveals the unsteady behavior of powder infiltration during the mold oscillation. © 2006 ISIJ.