Innovation Award for Rivian Hinge Pillar

Comptech AB won the METEF Innovation Award, in addition to the NADCA casting for the year 2022 for the Rivian hinge pillar. This part is made with an AlSi7Mg. Typically, it is a permanent mould casting alloy. In HPDC, the alloy causes high die wear. But in Rheocasting it is perfectly usable. This makes taking parts over from die casting into Rheocasting so easy. That’s not the reason for the awards. The reasons are the following:

• Outstanding mechanical properties:
  It is a complex part with long flow length and thick and thin sections. This makes it hard to get a good overall casting quality in HPDC. Even most Rheocasting methods failed to deliver a good casting quality. Many of them have a maximum solid fraction of around 25%. The key was the high solid fraction of 35 to 45%. This could only be achieved through the Comptech Rheometal process. It passed all required tests. Even the T6 heat treatment was not necessary. A T5 heat treatment was enough to deliver consistent mechanical properties of 170 MPa yield strength, 250 MPa ultimate tensile strength and 10% elongation.
  
  
• Impressive machine size reduction:
  When designing a part for HPDC, the ingate is set up to fill the complete part simultaneously. Therefore, a large gating and overflow system is needed. In Rheocasting, long flow lengths are no issue. So, the hinge pillar is designed with an ingate in the middle of the part and overflow systems at the end. This reduces the projected area from 4124 cm² to 2006 cm². That is only 50% of the area of HPDC. Therefore, the machine size could be reduced from a clamping force of 2800 tons to 1650 tons. This saves a lot of energy. In addition, smaller machines have lower hourly rates.
  
  
• Minimal carbon footprint:
  For this casting the alloy eccomelt356.2 from Eccomelt was used. It is a secondary alloy from post-consumer scrap and has the CO2 equivalent of 0,139 kg CO2 per kg Al. In comparison, the global average is about 16.7 kg CO2 per kg Al. Adding the casting process, T6 heat treatment (not the mentioned T5), machining and other processes, the carbon footprint of the part comes to 1.1 kg CO2 per kg Al. That is lower than most secondary alloys without delivery!
  
  

The Rivian Hinge Pillar shows what innovative ideas can do in the foundry world. If you want to present your company at such an award ceremony, take a look at the Rheocasting Expert on Demand. It is a remote consulting service that is designed to invent and market new solutions for your foundry. Schedule a free consultation below to get a first impression of the Rheocasting Expert on Demand experience.