【作者】 郄喜望；

【导师】 李廷举；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2007， 硕士

【摘要】 水平连铸近年来发展极为迅速，由于工艺设备简单等诸多优势，被广泛应用于铸造行业制备高质量铸件。随着国民经济的不断发展，对金属线材的需求量日益增加，同时对其质量及生产率提出了更高的要求。目前，超声场及电磁场以其独特的性能在材料改性及新材料制备中的应用研究越来越广泛。作者参与了国家自然科学基金“复合场作用下液体金属的运动行为及控制”这一重大研究课题，研究了超声场及电磁场作用下金属线材的制备及其改性，取得科研成果如下：改进优化了水平连铸装置，成功将超声场及电磁场引入到水平连铸制备金属线材的过程中。为了提高铸坯质量及生产效率，在超声场作用下探索出一套制备Al-Si合金线材最佳的工艺参数，此时合金铸坯的微观组织均匀细小，力学性能最佳。采用静态模拟实验，研究了超声场对Al-Si合金除气净化及晶粒细化的影响。超声场对铝熔体产生显著的除气净化效果，且超声处理时间存在最佳值；初步分析超声场作用下晶粒的球化、细化可能是由于超声空化泡破碎产生的过冷生核所引起。分析了不同励磁电流条件下，电磁场对Al-Si合金水平连铸冷却曲线、凝固组织及成分偏析的影响规律。在电磁场作用下，洛仑兹力作用于凝固区域的金属，对其产生搅拌及软接触两种作用，从而对金属的凝固过程产生影响。施加电磁场后，Al-Si合金的开始结晶温度上升，同时凝固速度加快结晶温度间隔变小；当励磁电流为100A时，电磁场对凝固区域合金的作用效果最好，铸坯晶粒均匀细小且成分偏析得到了抑制。研究了AZ31镁合金的熔炼工艺并探索了不同材质的结晶器AZ31镁合金的水平连铸。采用RJ-2熔剂对镁熔体进行保护及精炼，同时利用Ar气体保护法阻止镁液的燃烧。探索了石墨及不锈钢两种材质的结晶器下镁合金的水平连铸。更多还原

【Abstract】 Horizontal continuous casting is widely applied and researched for advantages such as simple facilities, etc. In recent years, with the development of industry and national economy, the needs of high quality metal wire increase quickly. Nowadays, ultrasonic field and electromagnetic field are successfully applied in material modification and new material preparation. The writer takes part in one project, which is "The dynamics and control of metal liquid with multi-field" supported by the National Natural Science Foundation. The preparation and modification of metal wire with ultrasonic field and electromagnetic field are researched. Main research results are as the following:Experimental apparatus of horizontal continuous casting is improved. The ultrasonic field and electromagnetic field are successfully conducted to prepare metal wire under horizontal continuous casting. In order to enhance the quality and production efficiency of Al-Si alloy ingots, the best technical parameters of horizontal continuous casting combined with ultrasonic field are established. The microstructures are uniform, fine and the mechanical properties are the best of all under these parameters. With ultrasonic field, the degassing effect and the grain refinement of Al-Si alloy are investigated using static experiment. The value of porosity volume of Al-Si alloy decreases obviously when the metal liquid is treated by ultrasonic field and the treatment time can be optimized. The expansion and collapse of cavities which results in the formation of nuclei may play the dominant important role in the formation of fine and globular grains.The influence of electromagnetic field on the cooling curve, solidification structure and solute segregation of horizontal continuously cast Al-Si alloy have been theoretically interpreted. Under electromagnetic field, Lorentz force acted on metal liquid can produce two effects: soft contact and electromagnetic stirring. The cooling curve shows that when the electromagnetic field is imposed during horizontal continuous casting, the nucleation temperature of the alloy increases and the solidification interval is shortened. When current is 100A, grains are refined and solute segregation is suppressed.To prevent the combustion of Mg, Mg melting is studied. The RJ-2 flux and Ar gas are used for protection and smelting. Based on experimental apparatus of horizontal continuously cast Al-Si alloy, the mold of graphite and stainless steel is respectively researched.更多还原