Prediction of Equiaxed Crystal Ratio in Continuously Cast Steel Slab by Simplified Columnar-to-Equiaxed Transition Model
A simplified prediction model of the equiaxed crystal ratio (ECR) in continuously cast slabs of ferritic stainless steel was investigated based on the columnar to equiaxed transition (CET) model proposed by J. D. Hunt. The present model assumes that CET occurs when a parameter <i>G</i>/<i>V</i><sup>1/2</sup> at a solid fraction of 0.3 is smaller than a critical value, <i>C</i><sub>ET</sub>. This model can explain comparatively well the effects of the casting speed, melt superheat, steel composition, intensity and position of the electromagnetic stirring (EMS), and secondary cooling intensity on measured ECR. The calculated results also show that an optimum EMS position and casting speed for maximizing ECR exist. Moreover, it was found that there is a proportional relationship between the best-fit values of <i>C</i><sub>ET</sub> and <i>N</i><sub>0</sub><sup>1/3</sup><i>C</i><sub>0</sub><sup>1/2</sup> calculated from measured data. This means that the simplified Hunt model is applicable to predict ECR in continuously cast slabs. The mechanism by which equiaxed crystal bands are generated is also discussed in relation to the behavior of <i>G</i>/<i>V</i><sup>1/2</sup>.
- ISIJ international
ISIJ international 46(6), 921-930, 2006-06-15
The Iron and Steel Institute of Japan