Observations on mold corner temperatures measured using thermocouples

Examination of thermocouple data from thermocouples near the strand corners in the casting mold has revealed that the corner temperatures can oscillate during steady state casting. The oscillation frequency is proportional to the casting speed, and is unrelated to the strand width. Thermocouples at the same elevation on opposite sides of a narrow face display periodic signals that are out of phase, while thermocouples in the same corner at different elevations have signals that show a phase or time lag between them. The time lag is less than half of the value obtained by dividing the distance between thermocouples by the casting speed. Similar oscillations have been observed on four different slab casters of different design. These observations and supporting calculations suggest that the cause of the temperature oscillations may be slowly varying fluid flow conditions in the casting mold.