Surface Roughness of Solidified Mold Flux in Continuous Casting Process.

Tsutsumi, K.; Nagasaka, Tetsuya; Hino, Mitsutaka

doi:10.2355/isijinternational.39.1150

Cited by 109 publications

(77 citation statements)

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

2002

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Primary crystallization field of cuspidine (3CaO · 2SiO 2 · CaF 2 ) has been experimentally determined in the 2CaO · SiO 2 -SiO 2 -CaF 2 system by quenching method and differential thermal analysis (DTA). Hermetically closed platinum capsules were used as a sample container to prevent fluorine loss in the form of HF and SiF 4 by reaction of CaF 2 with moisture or SiO 2 for quenching experiments. Combining the present study with the partial phase diagrams previously reported, the whole phase diagram of the CaO-SiO 2 -CaF 2 system has been developed. Cuspidine equilibrates with (2CaO · SiO 2 ) 2 CaF 2 , CaO · SiO 2 , 3CaO · 2SiO 2 , 2CaO · SiO 2 and CaF 2 in solid state. Cuspidine coexists with liquid phases at temperatures between 1 387 K and 1 680 K.

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Section: Introductionmentioning

confidence: 99%

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

2002

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“…[7][8][9] Normally, it is stated that the gap arises because the crystalline phase has a higher density than the glass, and therefore crystallization results in shrinkage of the solid flux layer. [10,11] In an investigation carried out to determine the surface roughness of solidified mold fluxes, it was found that this was in the range of 10 to 30 lm, when the crystalline phase precipitated; [12] this surface roughness was claimed to agree with the calculated thickness of the air gap assumed to form between the mold and the solidified slag layer. Furthermore, it was disclosed that the surface roughness of mold powder slags for casting medium-carbon steels is larger than that of mold slags used for low-carbon steels.…”

Section: Introductionmentioning

confidence: 79%

“…Furthermore, it was disclosed that the surface roughness of mold powder slags for casting medium-carbon steels is larger than that of mold slags used for low-carbon steels. [12] Other authors indicated that substantial shrinkage occurs in mold fluxes for medium-carbon steels due to larger volumetric ratio and faster growth rate of cuspidine, as compared to what occurs in mold fluxes for low-carbon steels; [13] however, no clear evidence of the shrinkage was provided.…”

Section: Introductionmentioning

confidence: 97%

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

Flores

2016

Metall Mater Trans B

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The slag film that forms between the shell and mold in steel continuous casting is key in regulating the heat transfer between them. Generally, the mechanisms proposed are related to the phenomena associated with the formation of crystals in the solid layer of the film, such as the appearance of internal pores and surface roughness, which decrease phononic conduction through the layer and interfacial gap with the mold, respectively, and the emergence of crystals themselves, which reduce the transmissivity of infrared radiation across the layer. Due to the importance of the solid layer, this study investigates experimentally the effective thermal resistance, R T , between a hot Inconel surface and a cold Cu surface separated by an initially glassy slag disk, made from powders for casting low and medium-carbon steels, denoted as A and B, respectively. In the tests, an initially mirror-polished disk is sandwiched for 10,800 seconds while the Inconel temperature, away from the disk face, is maintained steady at a value, T c , between 973 K and 1423 K (700°C and 1150°C)-below the liquidus temperature of the slags. The disks have a thickness, d t , between~0.7 and 3.2 mm. Over the range of conditions studied, mold slag B shows R T 33 pct larger than slag A, and microscopic observation of disks hints that the greater resistance arises from the larger porosity developed in B. This finding is supported by high-temperature confocal laser scanning microscope observations of the evolution of the surface of slag parallelepipeds encased between Pt sheets, which reveal that during devitrification the film surface moves outward not inward, contrary with what is widely claimed. This behavior would favor contact of the slag with the mold for both kinds of powders. However, in the case of slag A, the crystalline grains growing at or near the surface pack closely together, leaving only few and small empty spaces. In slag B, crystalline grains pack loosely and many and large empty spaces arise in and below the surface. Estimation from plant data shows R T values smaller than measured ones, suggesting that the process film slag thickness must be considerably thinner than those of laboratory disks. However, the difference in thermal resistance of both powders, averaged over the mold length, is close to the dissimilarity found in laboratory.

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“…In the present work, reproduction of the reactions between carbon, slag and iron was made at the ironmaking temperature. A confocal laser-scanning microscope combined with an infrared image-heating furnace, 9) which enabled us to make microscopic "in-situ" observation at high temperature, was used in the present work.…”

Section: Methodsmentioning

confidence: 99%

Carburization Degree of Iron Nugget Produced by Rapid Heating of Powdery Iron, Iron Oxide in Slag and Carbon Mixture

et al. 2008

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Surface Roughness of Solidified Mold Flux in Continuous Casting Process.

Cited by 109 publications

References 0 publications

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

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

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

Carburization Degree of Iron Nugget Produced by Rapid Heating of Powdery Iron, Iron Oxide in Slag and Carbon Mixture

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