(上海交通大学铸造研究所, 上海 200030
*西北工业大学凝固技术国家重点实验室, 西安 710072)
摘 要: 在自制的单晶连铸设备上，通过各工艺参数合理匹配，成功地制备出了表面光洁、直径8mm、长8～10m的铜单晶铸棒。通过理论分析和实验验证发现铜单晶连铸时固液界面位于铸型内，并呈凸出形状。铸型温度、连铸速度和冷却距离对固液界面的位置有很大的影响，其各工艺参数合理匹配，可使固液界面位置位于离铸型出口端2～3mm ；并且当连铸速度大于40mm/min时，固液界面的形状由凸变凹。当铸型温度逐渐降低(低于铜熔点温度)时，铸棒表面由粗糙变为拉伤，甚至出现严重的拉裂；而随着连铸速度的增加，形成铸棒表面拉伤(低温时)和条纹状沟槽(高温时)。铸棒内的杂晶是由于铸型温度低于铜的熔点(1 083℃)和连铸速度增加所致。当连铸速度大于40mm/min时，形成定向凝固的柱状晶铸棒。
关键字: 铜单晶 连续铸造 工艺参数 固液界面
（Shanghai Jiao Tong University, Shanghai 200030, P. R. China
State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi'an 710072, P. R. China）
Abstract:Single crystal copper rod, 8 mm in diameter and 8～10m in length with mirror-smooth surface has been obtained by using a self-made equipment under rational match of technological parameters. The solid-liquid interface is a convex shape and located in the inside of the mould during the continuous casting. It has been found that the mould temperature, the casting speed and the mould-cooler distance have effects on the solid-liquid interface position. The solid-liquid interface can be located at the inside of the mould extending 2～3mm from the mould exit under rational match of technological parameters, and at a casting speed above 40mm/min the shape of solid-liquid interface turns from convex shape to concave shape. When the mould temperature is less than 1083℃, which is the temperature of copper melting point, the surface appearance of the cast rod turns from rough surface to streaked surface, even forms cracked surface by drawing. With increasing casting speed, crack pits (low temperature) and ripple marks (high temperature) on the cast rods are formed. Stray crystals (equiaxed grains and columnar grains)in surface of the rod is formed because of lower mould temperature ( 1083 ℃) at location of the solidification front and increment of casting speed. At casting speed above 40mm/min, the rod contains unidirectional subtexture and occasional stray crystals.
Key words: single crystal copper; continuous casting ; solid-liquid interface; technological parameter
