A Heat Transfer Model For Strip Casting And Its Applicatio

Strip casting processes produce thin strips directly from liquidmetal, thereby eliminating rolling steps and associated annealingoperations. Due to the melt solidfying in directly contact with the stripcaster, the casting roller is the core component in strip casting. Sinceheat transfer in melt/roller interface determines the quality of the stripand technolgical parameters setting, it is necessary to study heat transferin the interface.In the present work, a two-dimensional model has been developedto simulate heat transfer in melt/substrate interface. In this model, theeffect of important variables in the interface on heat-transfer has beenpredicted. And several melt/substrate contacting experiments werecarried out to verify the model, under controlled laboratory conditionsdesigned to approximate the conditons encountered during the initialsolidifcation period in strip casting.The results suggest that maximum heat flux is affected by directly contacting area, oxide films, and thermophysical property of substrate.The huger directly contacting area, the bigger maximum heat flux. Andthe thicker oxide film and the bigger thermophysical property, the lessmaximum heat flux. Besides, average heat flux is mostly affected by airgap in the interface.The relation between heat transfer and the microstructure, dendriticstructure, and surface topography of soldification shell is also studies.The results suggest that microstructure has obvious relation withthermophysical property of substrate, not with heat flux. The lessthermophysical property of substrate, the less size of microstructuregroups. But dendritic structure has obvious relation with heat flux. Thebigger maximum heat flux, the less space of primary dendrite arms.It is defined that surface topography of soldification shell iscomposed by five types of topography. And surface topography ofsoldification shell, in certain, can reflect heat flux in the interface,because surface topography of soldification shell is influenced by meltwettability in melt/substrate interface and melt wettability determinesthe directly contacting area which influences heat flux. Therefore, therelation between heat flux and five types of topography is studed.