The Future of High-Wall Thickness Castings

The automotive industry, particularly the truck sector, is navigating new and challenging territory. With Euro 7 regulations imposing strict emissions controls, heavier aftertreatment systems for emissions, and substantial battery packs for electric vehicles, every kilogram counts. Trucks now face a dual challenge: meeting stringent environmental regulations while maintaining their payload capacity.

Traditionally, truck components subject to high fatigue loads, such as suspension arms, crossmembers, axle carriers, and transmission housings, have relied on gray iron castings produced through sand casting or permanent mould processes. While these castings provide necessary durability and stiffness, they result in significant weight penalties. For instance, gray iron, with a density of around 7.2 g/cm³, has nearly triple the density of A356 aluminium alloy, leading to considerably heavier components.

Why HPDC Falls Short

High Pressure Die Casting (HPDC) is often considered a candidate for replacing these heavier castings due to its rapid cycle times and cost-effectiveness. However, HPDC struggles immensely with the challenges posed by high-wall thickness components. The rapid solidification and turbulent metal flow, combined with thin gates in HPDC, typically cause porosity and shrinkage in thicker sections. This is detrimental to fatigue properties. Additionally, alloys commonly used in suspension and truck components, like AlSi7Mg (A356/A357), present castability, soldering and tool wear problems, further limiting their practical applicability. Any HPDC alloy requires new material validation, which triggers astronomical costs and lengthy trials. Still, these alloys will not meet the required fatigue loads due to the high amount of brittle eutectic content.

Bridging the Gap with Rheocasting

Rheocasting offers a compelling alternative. Rheocasting dramatically mitigates the inherent issues faced by both sand and HPDC processes:

The laminar, controlled slurry flow in Rheocasting drastically reduces porosity, achieving fatigue strength comparable to that of the iron castings.  The pocket warmer effect of the semi-solid slurry enables the slurry to travel further in the cavity, allowing for better feeding of the solidification shrinkage. A high solid fraction further reduces the shrinkage potential.

Still, Rheocasting is just a different melt preparation for HPDC cells. So, you get the full efficiency of the short cycle times of HPDC and the capabilities of die-casting.

From Insights to new Business Opportunities

The stringent requirements introduced by Euro 7 have accelerated the need to adopt advanced manufacturing techniques, such as Rheocasting. By transitioning from traditional sand and permanent mould castings to Rheocasting, OEMs and foundries can achieve substantial reductions in structural weight, improved durability under fatigue conditions, and cost efficiencies previously unattainable.

The time to act is now. Foundries and component manufacturers that adopt Rheocasting will not only meet regulatory demands but will also position themselves advantageously in a highly competitive market.

In conclusion, Rheocasting presents an innovative, cost-effective solution, perfectly aligning with the industry’s urgent need for lightweight, robust, and durable components under stringent fatigue conditions. Take advantage of Rheocasting to secure your competitive edge and transform regulatory challenges into opportunities for growth and innovation.

Learn how to utilise Rheoasting to develop new business outside the automotive industry. Reserve your spot in the Rheocasting Masterclass today!