| The thermal stability and hardness of Al2O3particles are ideal and its cost is low, but the wettability between the molten steel and Al2O3particles is bad, the melting point, viscosity, cooling speed of the molten steel are high, so the preparation of Al2O3P/steel matrix composites is very difficult. This paper firstly coated the low thermal conductivity, high thermal stability insulation layer which is mainly consist with the quartz particles at the steel mold’s internal surface, then Al2O3P/steel composites was successfully prepared by the squeeze impregnation method.The molten steel in infiltration system continues to maintain liquid status, which is a prerequisite to the high temperature molten steel impregnates into ceramic particles. Therefore, the temperature field of infiltration system consisted of steel mold-thermal barrier coating-liquid steel-preform must have an important influence on infiltration effect of the composites. This paper combined numerical simuiation technology and experimental measure temperature methods, actually measured thermal parameters of the materials and recorded temperature cooling curves of different key points by using multi-channel temperature logger and thermocouples firstly, then used the measured datas as correction simulatlon parameters to ensure the reliability of the simulation results. This paper focuses on the insulation layer thickness, extrusion pressure, the preform preheating temperature and pouring temperature of the liquid steel on the impact of infiltration system’s temperature field, liquid retention time and the thickness of composites.The study found:When the insulation layer thickness is in the range of5mm, liquid duration is very sensitive to insulation layer thickness, slight thickness increase can effectively improve liquid retention time; When the thickness is close to13mm, increasing the thickness of the insulation layer is no longer can effectively improve the retention time of the liquid steel. Extrusion pressure have a significant influence on the temperature field, the steel cooled to below the freezing point instantly when the pressure is applied on liquid steel, the higher applled pressure, the greater reducing temperature drop. This phenomenon is presumably due to the molten steel was forced into the preform holes under the effect of pressure, the interface contact heat resistance between the molten steel and the preform reduced so that the strengthened heat transfer led to the temperature steep drop. With preform preheating temperature increased, the liquid status duration time of the molten steel almost linearly increased. If extrusion pressure is same, the preform preheating temperature increase, the temperature drop caused by the pressure at a certain degree of inhibition. when the preform preheating temperature is670℃, the temperature of plunged almost disappeared. Pouring temperature is from1480℃to1500℃, the residence time of the molten steel where the leading edge is significantly increased; when the temperature is from1600℃to1640℃, liquid residence time of the molten steel is increased only from312s to333s. The pouring temperature should slightly exceed1600℃, which extend the duration time of the molten steel effectively, prevent overheating caused big grains and provide a time opportunity to let the liquid steel into the preform.Composites’thickness results under different process parameters are consistent with the infiltration system’s temperature distribution. When the leading edge’s temperature of infiltration system is low, pressure impregnation thickness depends on the size of infiltration pressure; Under the same pressure, the slower leading edge’s liquid steel cool, the longer the duration time of liquid steel is and the thicker composites’thickness are. |
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