A Billion-Dollar Casting Opportunity

In 2026, the European Union’s F-Gas Ban will come into force, phasing out high-global-warming-potential fluorinated gases like R-134a. This shift will immediately affect automotive applications, where most compressor housings are currently cast on HPDC machines.

The Issues with HPDC Castings

Those machines have long supplied millions of parts for R-134a-based systems operating at around 12–15 bar. Once the industry transitions to CO₂ (R-744), where pressures can easily reach 130–160 bar, the normal HPDC methods can no longer maintain the necessary leak-tightness. The smaller CO₂ molecule, coupled with higher operating pressures, makes porosity networks in conventional castings a critical point of failure, and even impregnation treatments can’t overcome this issue in most cases.

The problem becomes apparent when considering how high-silicon alloys such as ADC-12 and AlSi10Mg are used in HPDC to speed up solidification. They show good castability, but shrinkage gets distributed throughout the part, and that’s generally tolerable for R-134a so long as impregnation is sufficient to seal it. At far higher pressures with a much smaller molecule, the chance of leaks skyrockets, forcing suppliers to seek alternative manufacturing processes. Forging comes to mind first because its massive forming pressures eliminate virtually all porosity. Still, it is both capacity-limited and five to ten times more expensive than HPDC. Low-pressure die casting can also deliver better integrity but tends to be slower and costlier than HPDC, and it does not tap into the installed base of thousands of HPDC machines worldwide.

Rheocasting brings Leak-Tightness and Profitability

Rheocasting addresses these problems by introducing semisolid metal into the die-casting process. Instead of injecting fully liquid aluminium, a slurry with a solid fraction of about 35 per cent is prepared in Rheocasting. The high solid fraction drastically reduces the shrinkage during solidification and avoids porosity networks. The laminar filling also reduces the metal meetings, which are a major contributor to the leakage in CO2 and Helium testing.

A key advantage is that Rheocasting can retrofit existing HPDC machines. Foundries with hundreds of idle or underutilized die-casting cells, previously geared toward R-134a compressor housings, can transition to CO₂-capable parts by investing in slurry-making technology rather than replacing entire lines with forging equipment or low-pressure die casting. Many OEMs and Tier 1 suppliers find themselves in a bind because they see that their HPDC supply base cannot handle the new high-pressure, leak-tight requirements. Forging is expensive, and low-pressure die casting falls short on throughput. Rheocasting is the perfect combination that allows existing HPDC assets to become competitive again.

The overall result is a unique market opportunity created by the EU F-Gas Ban. Hundreds of HPDC machines worldwide, which otherwise might lose their compressor housing programs, can be adapted to Rheocasting. Tier 1 suppliers and OEMs seeking leak-tight compressor housings for CO₂ systems will look for foundries able to deliver reliable parts at competitive prices. For many foundries, the investment in slurry-processing equipment allows a stable transition from legacy R-134a to future-proof CO₂ designs. Rheocasting offers a genuine chance to avoid obsolescence, maintain valuable customer relationships, and even outcompete forging or low-pressure die casting in terms of cost, production volume, and overall profitability.

Unlock your portion of the Billion-Dollar Opportunity with the Rheocasting Expert on-Demand from Casting-Campus GmbH. Schedule a free Consultation Call below and inquire for more insights.