Thermal Gradients Behaviour during the C-E Transition within Solidifying Massive Roll

Abstract

Columnar or equiaxed structure selection and particularly the C→E transition in the solidifying massive rolls is shown as the result of changes in heat transfer. The numerical treatment of heat transfer allows to separate the temperature field for columnar structure formation from equiaxed structure formation. An area where transition from columnar into equiaxed structure occurs, C→E≡CET is also distinguished. The current model requires the transformation of the calculated temperature field into the thermal gradients’ field. Thermal gradients are approximately constant during the examined C→E transition according to the numerical simulation. This result is in accordance with the Hunt’s theoretical predictions. The localization of the structural transition (CET) in space and in time is also shown within the map which yields from the temperature field.