Preparation And Application Of Non-Newtonian Fluid Mold Flux Containing N Series And Al Series

Because of the relatively low viscosity of mold flux in the retention area of continuous casting mold,slag entrainment is easy to occur.However,in the lubrication area of the mold,due to its relatively high viscosity,steel leakage is easy to occur.In view of the above problems,it is necessary to develop mold flux with relatively high viscosity at low shear rate and relatively low viscosity at high shear rate,i.e.,non-newtonian fluid mold flux,to meet the requirements of high tensile speed continuous casting.By adding Si3N4 and Al2O3 to low carbon steel and medium carbon steel respectively,four series of mold flux were prepared to make them own non-newtonian fluid characteristics.The rheological properties of the four series of mold flux were tested by a viscometer with adjustable rotational speed.Then,Raman spectroscopy and molecular dynamics simulation were used to study the microstructure of mold flux,analyze the changes of microstructure of mold flux under different components and analyze the mechanism of shear thinning.The results show that the shear thinning property is related to the degree of molecular polymerization.Then the infrared emission system was used to conduct heat transfer tests on medium carbon steel mold flux,carbon steel mold flux in N series non-newtonian fluid and carbon steel mold flux in Al series non-newtonian fluid.It was found that adding Si3N4 and Al2O3 into medium carbon steel mold flux could not only change its rheological property,but also increase heat resistance and improve heat transfer.The crystallization performance of carbon steel mold flux in non-newtonian fluid is better than that of carbon steel mold flux.Finally,the physical and chemical properties of the four series of mold flux were tested.On the premise of satisfying the reasonable physical and chemical properties,the samples with the best shear thinning properties were selected for the billet test.Compared with the traditional low carbon steel slag,the slag rolling phenomenon is obviously improved by pouring non-newtonian fluid slag.Compared with traditional medium carbon steel slag,the incidence of longitudinal cracks in billet cast by non-newtonian fluid slag is obviously reduced.The quality of billet is greatly improved and the benefit is gained for the enterprise.Figure 40;Table 35;Reference 58...