Melting and floating processes of inorganic materials in molten steel: Visualization physical simulation and mathematical modelling

It has been demonstrated that heat absorption method by using the inorganic material rod to cool the molten steel can significantly reduce the macrosegregation level of the large steel ingot. However, owing to the opacity of the molten steel, the physical mechanism of the heat absorption method is not clear. In this work, a transparent hydraulic physical model with water and paraffin wax was built to simulate the melting and floating processes of inorganic materials in the molten steel. A mathematical simulation was also carried out to analyze the connection between the actual ingot and the physical model. Results show that it is feasible to simulate the molten steel and inorganic materials with water and paraffin wax. With the help of the physical model, the process of the melting of paraffin wax and its floating to the surface of water were clearly observed, during which the temperature of water at some characteristic positions in the mold was recorded. The visualization findings demonstrate that the melting and floating processes of paraffin wax can help to bring the heat from the center of the mold to the top surface more quickly, which reduces the superheat and significantly accelerates the cooling rate of water. The experimental results show that for the water with a certain superheat, the use of a larger mass of paraffin wax can accelerate the cooling of the water, but there is a risk of incomplete melting of the paraffin wax. A higher superheat of water will lead to a quicker melting rate for a given mass of paraffin wax, while a lower superheat leads to the incomplete melting of paraffin wax as well.