Our Alloy Landscape is Changing

The foundry industry is facing several challenges simultaneously. Automotive volumes have dropped, energy and labour costs have skyrocketed, and sustainable castings require investments. In addition, the transformation of vehicles towards EVs, hybrids, and software-defined vehicles changes the requirements for castings.

Low Requirement Castings leave Europe

Combine all of these developments and change the dynamic of our industry. There are millions of castings out there that certainly don’t require high properties. They just need to be made out of aluminium. Typical examples are brackets and many types of housing. Even engine blocks get smaller and smaller. Many of them are produced in 226, AlSi9Cu3, or similar alloys. They are cheap and, most of the time, made from 100% scrap.

Most of these castings are purchased by Tier 1s or Tier 2s. In their sandwich role, they face even higher price pressure. One way to increase the margin is by buying the castings from cheaper foundries in low-labour-cost countries. This leads to the tendency for many “simple” castings to leave Europe or North America to reduce costs.

The Secondary Alloy Dilemma

The castings that meet the new strength, elongation, and thermal conductivity requirements use different alloys. They are often based on AlSi7Mg, AlSi7MnMg, AlSi10Mg(Fe), and AlSi10MnMg. These alloys have a higher elongation, making them crash-relevant and easier to connect by riveting or welding with the rest of the car. However, these alloys’ specifications only allow minimal iron, copper, and zinc quantities.

OEMs are aware of this dilemma and have started to adjust their internal specifications to allow more of these impurities. However, the allowance is too small to drastically change the recycling content, but it is a step in the right direction.

The dilemma for alloy producers is that the scrap they can purchase contains high copper and iron content, whereas the increasing market share alloys contain none. At the same time, OEMs make sustainability a hard requirement, like mechanical properties. So, the big question is how to fulfil that spread in demand and what to do with these high-copper alloys, as you cannot use them for any modern HPDC alloy.

Sustainable Castings with Rheocasting

The high copper scrap doesn’t help in Rheocasting for the new applications either. However, the scrap with a high iron content is a great way to utilize unusable scrap streams for HPDC in Rheocasting.

Rheocasting works well with high iron contents as it does not form the intermetallic AlSiFe needles and does not require silicon additions to increase castability. This is excellent because primary silicon has a high carbon footprint of around 9 kg CO2 per kg Si. In Rheocasing, an AlSi2 is cast as well as an AlSi7. The area between 2 and 7 percent is white space on the alloy map as the silicon content is too high for sheet metal and too low for casting alloys.

Therefore, Rheocasting is the key to achieving truly sustainable castings! Learn about how to produce sustainable castings in the Rheocasting Workshop from Casting-Campus GmbH. Sign up for the Free Consultation Call down below to inquire about more information.