Mold Simulator Study of Heat Transfer Phenomenon During the Initial Solidification in Continuous Casting Mold

Abstract

In this paper, mold simulator trials were firstly carried out to study the phenomena of the initial shell solidification of molten steel and the heat transfer across the initial shell to the infiltrated mold/shell slag film and mold. Second, a one-dimensional inverse heat transfer problem for solidification (1DITPS) was built to determine the temperature distribution and the heat transfer behavior through the solidifying shell from the measured shell thickness. Third, the mold wall temperature field was recovered by a 2DIHCP mathematical model from the measured in-mold wall temperatures. Finally, coupled with the measured slag film thickness and the calculations of 1DITPS and 2DIHCP, the thermal resistance and the thickness of liquid slag film in the vicinity of the meniscus were evaluated. The experiment results show that: the total mold/shell thermal resistance, the mold/slag interfacial thermal resistance, the liquid film thermal resistance, and the solid film thermal resistance is 8.0 to 14.9 9 10 À4 , 2.7 to 4.8 9 10 À4 , 1.5 to 4.6 9 10 À4 , and 3.9 to 6.8 9 10 À4 m 2 K/W, respectively. The percentage of mold/slag interfacial thermal resistance, liquid film thermal resistance, and solid film thermal resistance over the total mold/shell thermal resistance is 27.5 to 34.4, 17.2 to 34.0, and 38.5 to 48.8 pct, respectively. The ratio of radiation heat flux is around 14.1 to 51.9 pct in the liquid slag film.

Mold Simulator Study of Effect of Mold Oscillation Frequency on Heat Transfer and Lubrication of Mold Flux

“…cess A one-Dimensional Inverse Heat Transfer Problem for Solidification (1DITPS) mathematic model was adopted to determine the temperature distribution of the solidifying shell from the measured shell thickness. 33) In Fig. 1(b), the initial temperature of steel is melt temperature (Table 3), and the boundary conditions are set as heat flux q(t) = 0 at the shell surface (x' = 0) side and is insulated at x' = l side where the liquid steel is in contact with the wall of furnace (MgO).…”

“…The 1DITPS mathematic model is capable of determined the heat-transfer process of solidifying shell from the measured shell thickness and shows a good anti-interference ability of inverse results to the thickness measurement noise, and the detailed description of this mathematic model has been well illustrated in our previous study. 33) 3. Resuilts and Discussion…”

“…5,27) and the surface roughness of slag at the mold side that will act as additional barriers for heat transfer. 32,33) Besides, the casting conditions also have effect on the mold heat flux. It is generally reported that the heat flux increased with the increase of casting speed and superheat.…”

Insight into Breakout Shell of a Bloom Casting by Its Dendritic Morphology and a New Mathematical Model

“…Most of the strand surface defects, such as cracks, oscillation marks, ripples, depression even breakout, originate in the mold region with close relationship to shell initial growth. [1][2][3][4][5][6][7][8][9][10] Therefore, many methods to measure the shell thickness have been proposed. In the 1980s, Brimacombe [1] and Suzuki [2] added a radioactive tracer(198Au) to the liquid pool during steel casting to reveal the shape of solid shell.…”

Hook evolution and inclusion entrapment during initial solidification process of continuous casting slab

“…Using numerical methods, Thomas and Mills et al [16][17][18] confirmed that the formation of a hook-type OM results from the overflow of the liquid steel over the partially solidifying meniscus; the mold oscillation and narrow width of the liquid mold flux film between the mold and shell make numerical calculations extremely difficult. Recent high-temperature experiments performed by Badri and Wang confirmed that the formation of hook-type OMs is associated with partial solidification of the meniscus; in addition, the partial solidification of the meniscus was shown to be accompanied by an increase in the mold heat flux in the meniscus area [19][20][21][22][23][24].…”