Heat Transfer between Mold and Strand through Mold Flux Film in Continuous Casting of Steel.

Stability of Cuspidine (3CaO 2SiO2 CaF2) and Phase Relations in the CaO-SiO2-CaF2 System.

“…A crystalline layer in slag film yields larger thermal resistance by producing air gap at the flux/mold interface and scattering infrared radiation from steel. [3][4][5][6][7][8] The authors have focused on the compound, cuspidine (3CaO · 2SiO 2 · CaF 2 ), which crystallizes in the crystalline layer in flux films. [9][10][11] Since cuspidine primarily crystallizes in almost all of commercial mold fluxes, controlling the crystallinity is a key factor to control the horizontal heat flux.…”

Study of Shell-Mold Thermal Resistance: Laboratory Measurements, Estimation from Compact Strip Production Plant Data, and Observation of Simulated Flux-Mold Interface

“…[14] Also, an interfacial thermal resistance equivalent to an air gap of 20 to 50 lm was estimated, and the radiative heat transfer was reported to amount to 20 pct of the total heat flux, with crystallization inhibiting radiative heat transfer. [15] The interfacial thermal resistance was found to increase with flux film thickness, and for the same thickness, the interfacial resistance was larger for fluxes used for medium-carbon steel than for fluxes dedicated to low-carbon steels; this behavior was attributed to greater crystallization of the first kind of powders. [16] Furthermore, it was claimed that the structure of flux films obtained in experiments is similar to that displayed by films taken from the mold wall after continuous casting, but there is uncertainty since the total thickness of the films recovered from the mold after casting might be different from those existing during casting.…”

“…This requires that the heating source, simulating the strand, has sufficient power to balance the heat extracted by a water-or air-cooled body simulating the mold and that steady-state conditions are established. Heating methods involved direct resistance heating, [14] electrical resistance cartridges, [15] electromagnetic induction heating, [16,17] and gas burners. [7] These kinds of methods were used with slag film thicknesses between 0.5 and 3.0 mm and showed that the heat flux can vary considerably with slag composition.…”

“…For studying heat transfer, different methods were devised and, according to their experimental principles, were classified into three categories: (1) sandwiching a mold slag layer between hot and cold solid walls, [7,[14][15][16][17] (2) dipping a cold finger into molten slag [8,9,18,19] or into a bath of molten slag and steel, [20,21] and (3) exposing a mold slag layer to infrared radiation. [22][23][24][25] In the sandwiching methods, measures are taken to establish linear temperature gradients through the measuring system, which consists of hot body, mold flux film, and cold body.…”

“…[7] Overall (i.e., film plus interfacial), effective thermal resistances, between 0.7 9 10 À3 and 5.5 9 10 À3 m 2 K/W, were reported for film thicknesses between 0.5 and 3.7 mm. [7,[15][16][17] Cold finger dipping methods deal with freezing a slag shell over a cold body that is immersed into a molten bath and with recording of temperatures, at certain locations, as a function of time. [8,9,[18][19][20][21] The temperature data obtained are converted to heat flux values by solving a one- [9,18,19] or two-dimensional [20] inverse heat conduction problem.…”