下引法连铸单晶铜试验研究

Study on Solidification Process of Single Crystal Copper by Downward Continuous Casting

利用自制下引式真空熔炼、氩气保护连续定向凝固设备制备出Φ16 mm的单晶纯铜棒材,研究了各工艺参数对连铸单晶铜凝固过程中温度分布的影响,分析了铸锭凝固过程中的表面质量和凝固组织的变化情况。结果表明：拉坯速度、熔体温度、冷却水量等工艺参数对固液界面的形状和位置有显著影响,并通过影响固液界面位置和形状来作用于凝固过程。连铸单晶铜凝固过程中,铜在结晶器内熔点位置即为固液界面位置,理想的固液界面位置在距离结晶器出口30-40 mm处;铸锭凝固过程中逐渐淘汰的晶面为（311）、（220）和（111）,最后单晶生长的晶面为（200）,其晶体生长方向为[100]。

Single crystal copper rod（Φ16 mm）was prepared by downward continuous casting with the self-developed vacuum melting and argon gas protection equipment.Effect of the process parameters on the temperature distribution during the solidification was researched,and the change of the surface quality and the solidification structure of the rod was analyzed.The results show that the process parameters including the casting speed,the melt temperature and the cooling water amount have a significant impact on the shape and location of solid-liquid interface,and by which affect the solidification process.During the continuous casting,the location of the copper melting point is on the solid-liquid interface;the ideal location of solid-liquid interface is 30-40 mm above the exit of the mold.The growth crystal faces（311）,（220）and（111）are eliminated gradually during the solidification.Finally,the crystal face for growth of single crystal is（200）,and its growing orientation is .