空心管坯热顶电磁连铸工艺的研究

根据空心管坯的特点,提出了热顶技术和冷坩埚技术相结合的空心管坯电磁连续铸造的工艺思想。采用低熔点的Sn-4.5% Pb(质量分数,下同)合金进行了模拟试验,成功制备了φ60 mm?5 mm的空心管坯。研究了热顶和冷坩埚式外结晶器对铸型内磁场分布的影响,分析了电磁场对空心管坯质量的影响。结果表明:采用带屏蔽罩的热顶和冷坩埚式外结晶器,优化了铸型内的磁场分布;当施加功率为12 kW、频率为2 500 Hz的中频电磁场时,得到了表面光滑、宏观凝固组织中具有高等轴晶比率的高质量空心管坯。

Research on Hot-top Electromagnetic Continuous Casting of Hollow Billets

According to the characteristics of hollow billets, a hot-top electromagnetic continuous casting process is proposed, based on a combination of the hot-top technique and a cold crucible. Sn-4.5%Pb (wt%) was used as the experimental material to study the effect of hot-top and cold crucible outer mould on the distribution of electromagnetic field. The effect of the electromagnetic field on the quality of hollow billets was analyzed. The results indicated that use of the hot-top with screen and cold crucible outer mould, while imposing an electro- magnetic field of 12 kW with the frequency of 2 500, can improve the distribution of electromagnetic field in the mold. In this ways high quality hollow billets can be obtained, whose solidification macrostructure consists of equiaxed grains of high ratio and a smoother surface.