In die casting, it has been shown that the hypereutectic Al-25%Si alloy has excellent fluidity. In this study we clarified that the semisolid Al-25%Si alloy showed better fluidity than did the molten-metal ADC12 alloy, which is a popular AlSi-Cu alloy for die casting. The result obtained suggests that Al-25%Si alloy is suitable for manufacturing thin die cast products. By using the Al-25%Si alloy, a heat sink model having fins with 50 mm height, thin tops 0.5 mm thick and a draft angle of 0.5°, could be successfully cast at a plunger speed 1.6 m･s-1. It was found that heat dispersion characteristics ware not influenced by the reduction in fin thickness. It is concluded that thinner fins manufactured using the semisolid Al-25%Si alloy are useful in reducing the production weight of the heat sink.
A semicontinuous caster for a plate and a clad plate of light metals was designed, assembled and tested. It was composed of a cooling substrate, a copper roll, deformable side dam plates and a pouring unit of molten metal. When a clad plate was cast, a partition roll was mounted to prevent the mixing of the two molten metals. A plate with thickness ranging from 10 mm to 30 mm could be cast. A clad plate with a clear interface between the two plates could also be cast. The plates were strongly bonded at the interface.
In this study, a single-casting-wheel caster equipped with rotating side-dam plates was proposed to cast a wire rod thinner than 180 mm2. This caster has the advantages of not needing the downstream process and downsizing of the equipment. Rotating side-dam plates solved the jamming of bar dragging. The following four types of rotating side-dam plates were tested. Type A and Type C: Boron nitride (BN) was directly sprayed on to the rotating side-dam plates. Type B1: BN-coated insulator sheet with 2 mm thickness was attached to the rotating side-dam plates. Type B2: BN-coated paper with 0.5 mm thickness was attached. In Type A, Type B1, and Type B2, a puddle of molten metal was formed on the casting wheel. In Type C, the bar was cast by a puddleless pouring method. In Types A, B1, and B2, the sound bars could not be cast. In Type C, the sound bars with rectangular or convex cross section were cast. The cross-sectional area of the convex bars was from 149 mm2 to 59 mm2 and the cross-sectional area of the rectangular bars was from 111 mm2 to 51 mm2 when the casting wheel speed and side-dam plate speed were from 2.5 m/min to 10 m/min.