A review: influence of refractories on steel quality

Abstract

-Chemistry and inclusion control are two of the main keys to the production of quality steel products. The refractory materials have a direct influence on the quality of elaborate grades at different levels: (i) The control of solute elements such as carbon, sulphur, nitrogen, hydrogen, oxygen. (ii) The prevention of non-metallic inclusions. A good knowledge of the metal-slag-refractory products interactions is consequently necessary in order to have a better control of elaboration procedures. Among all the points brought up, we could mention all the developments that will limit the contribution of refractory products in clogging phenomena, carbon pick up and atmospheric re-oxidation, in conjunction with efforts of the metallurgists to produce clean steels.

Functionalized Carbon‐Bonded Filters with an Open Porous Alumina Coating: Impact of Time on Interactions and Steel Cleanliness

“…They suggested, however, that alumina of the filter partially dissolved in molten steel. That reaction should have been accelerated by carbon, which is in accordance to the discussion of Poirier et al [13,14] As the system was out of equilibrium, alumina may have precipitated at the filter surface due to a changing oxygen activity within the melt.…”

“…In summary, they concluded that carbon of the refractory has triggered the clogging phenomena. [13,14] Also, we deduce from our results that carbon of the carbon-bonded alumina had an essential influence on the interfacial reactions between filter and steel melt due to the microstructural changes within the carbon-bonded alumina filter we observed. To our present knowledge, these microstructural changes resulted from carbo-thermal reactions within the carbon-bonded filter material.…”

“…For submerged entry nozzles (Al 2 O 3 -C), Poirier et al [13,14] described clogging as a result of dissolved carbon from the refractory in molten steel. The aluminum activity in steel increased with the amount of carbon dissolved in steel.…”

“…[24] According to them, these changes emanated from decarburization that had been triggered by iron acting as catalyst. [13,18,19,24,25] Section 4 describes the decarburization in more details. Despite some cracks, which were probably caused by the strong thermo-shock, no distinct changes were observed at the coating/steel interface after 1 min testing time.…”

“…To diminish clogging, several studies have focused on the origin, formation, and growth of non-metallic inclusions in Al-killed steel on the one hand, as well as on the interactions of Alkilled steel and carbon-bonded alumina refractories. [1,[12][13][14][15][16][17] For steel melt filtration, however, the time factor of these interactions is essential. To the authors' knowledge, such tests have been carried out by Storti et al [18] only in form of shorttime immersion tests (10 s and 30 s) of multi-walled carbon nanotubes coated Al 2 O 3 -C filters.…”