Production of Al–Cu and Al–Si Alloy Rods by a Moldless Upward Continuous Casting Process

Abstract

Al–Cu and Al–Si alloy round rods were experimentally produced by using a moldless upward continuous casting apparatus. Al–Cu and Al–Si alloys were selected because they have a wide solidification range and solidify in a mushy type or in a eutectic manner. Effects of the the alloying element, the superheat of molten metal, the upward withdrawal speed, and the strand rotation upon the diameter, the taper, the macrostructure, the microstructure, and the surface conditions of the cast strand were investigated, with the following results.
The diameter and the taper of the alloy cast strand were determined by the superheat of molten metal, the withdrawal speed and the strand cooling intensity, similar to those of aluminum having no solidification range and solidifying by skin formation. The cast strand consisted of columnar grains solidified completely unidirectionally. The diameter of the alloy cast strand was smaller than that of aluminum one, which was considered to be due to the low heat conductivity of the alloy. The size of the dendrite observed in the cross section was nearly proportional to the diameter of the cast strand despite of the different combination of the superheat and the withdrawal speed.