Efficiency in Steel Melting: Ladle Development

Effective ladle design and use is important for steel casting production. In foundry operations, the ladle temperature of the liquid steel is typically 150 to 250°F above the steel\u27s melting point to compensate for the heat losses in small ladles and the associated high cooling rates from the large surface area to volume ratios. Higher superheat is also necessary to provide sufficient steel fluidity to properly fill the mold cavity. In spite of the relatively short time that the steel is in contact with the ladle lining, the huge thermal gradients in the lining drive high values of heat flow through the refractory surface. Heat transfer between the melt and the ladle lining as well as the associated heat losses in foundry linings are analyzed in this paper. Initial information was taken from a survey of steel foundries and from industrial measurements at seven foundries. Temperature measurements were done with thermocouples and infrared cameras. Fluent software was used for modeling unsteady heat transfer in ladles. The influence of the thermal properties of different ceramic materials typically used for steel ladle linings on heat losses during use was analyzed. A novel class of ladle linings being developed at UMR based on porous ceramics has the potential of significantly decreasing the heat losses during use in addition to saving considerable ladle preheat energy. This paper reviews progress in developing and testing these linings