Simulation and Characterization on Heat Transfer through Mould Slag Film

As one of the most important factors on product surface quality and casting practice, the heat transfer across the interfacial layers in continuous cast mould is greatly affected by the formation of mould slag film between the solidifying shell and the mould. So far, many methods have been presented to measure the heat transfer of mould slag; however, few of them could be easily applied to represent the real heat transfer across the mould interfacial gap. An apparatus used for mould slag film heat transfer measurement is presented in the current paper. The apparatus is used to simulate the heat transfer across the mould slag film. According to the measurement, four parameters are selected as a standard to characterize the heat transfer of the mould slag. The parameters include maximum heat flux (liquid slag), characteristic time, heat flux at meniscus, and average heat flux. Two measurements on different mould slags verify that: 1) the standard could represent the difference in heat transfer between medium carbon steel and low carbon steel mould slag; 2) the average heat flux is a key factor to indicate the overall heat transfer in casting mould; 3) the formed solid slag film in experiment is identical to the real mould, including the morphology, composition, grain size, and thickness. The experiment simulation offers an effective approach to study the formation and evaluation of slag film inside the mould.