New Addressable Applications for Rheocasting to Escape from an Oversupplied Market

Abstract

The current market change of aluminium HPDC castings started with the “Dieselgate”. First, there was a shift from diesel to petrol engines. In the second step, hybrid and battery-powered cars gained significant market shares in sales statistics. Therefore, lucrative powertrain components are falling away. As powertrain foundries still want to utilize their machines to capacity, they are pushing into the structural castings market. As a result, there is an oversupply of casting machines here, which massively depresses prices and, thus, margins for tenders. With rising energy costs, these declining margins were eaten up, bringing foundries into crisis. Implementing Rheocasting at the existing die-casting cells is the solution to move into new market shares that are now not accessible in conventional HPDC.One of the new applications is electronic housings, high wall thickness parts, and fatigue bearing parts. These parts are commonly manufactured in sand or gravity castings because of their high wall thickness and low tolerance of porosity. Rheocasting is the perfect process for high-wall thickness components. Because of the semisolid melt preparation and the lamellar filling behavior, these components can be manufactured from the same alloy without pores or voids.This flow behavior of the semisolid slurry also results in a longer flow length. Slower casting speeds and lower pressure settings result in lower clamping forces. This gives an advantage in production costs and targets battery constructions made of castings and sheet metal. Structural battery housings must be leak-tight, even in a crash event. Having it in one casting instead of an assembly reduces the leakage area and improves crash performance.Another industry that relies on Rheocasting is the telecommunications industry. The power electronics in these 5G modules are significantly larger and generate much more waste heat. Until now, many antennas have been actively cooled or milled from a block of aluminum. The milled housings are significantly too expensive to enable series production. Therefore, the goal is to reproduce the passively cooled modules in die casting. Due to the process, the thermal conductivity in conventional HPDC is around 120 to 130 W/m*K. Similarly, no slim cooling fins can be formed. Only the Rheocasting process makes it possible to cast other alloys with low proportions of alloying elements, such as AlSi2Mn. This allows fins with a wall thickness of down to 0.4 mm and thermal conductivity of up to 190 W/m*K.Rheocasting enables access to market segments out of reach. These bring an unbeatable cost advantage against the current suppliers: gravity and sand casters. The low cycle time in Rheocasting brings back the high margins needed to sustain the business. Also, these products can be delivered with even better properties on smaller casting machines.