Go with the flow
How AMAG became a premium supplier of cast aluminium alloys
In the early 1990s, the smelter in Ranshofen was decommissioned, with the site since shifting its activities to the production of high-quality cast and wrought aluminium alloys based on the use of solid metals and with a focus on recycling. At the same time, a clear focus on our customers has remained the foundation of our corporate philosophy and promotes long-term cooperation in a spirit of partnership. In addition to its role as a product supplier, AMAG also considers itself an innovator, a technology specialist, an expert consultant on the entire production chain and a manufacturer of sustainable products. Reducing CO2 emissions has become an increasingly important objective in recent years. In this context, transporting cast alloys in a liquid state can help to reduce associated CO2 emissions.
Adopting such a holistic perspective makes it possible to continuously optimize the benefits for our customers. AMAG casting has significantly increased its turnover by focusing on this crucial factor and aims to increase its sales volumes to exceed 100,000 tons in the years ahead.
Promoting the use of liquid aluminium
The company reached an initial (yet significant) milestone in its development in 2006 by securing the first major customer for its liquid aluminum in its home market of Austria. When the first issue of AluReport was published in 2008, AMAG had already gained two years’ experience in the transport of liquid aluminum (Figures 1, 3). At that time, the company focused primarily on the conventional die cast alloy AlSi9Cu3(Fe). The distance to its customer was around 300 km.Over time, improvements in thermally insulated transport crucibles markedly reduced the temperature losses during transport, which significantly expanded the range of the company’s liquid aluminium transports. Consequently, AMAG is now able to serve customers located up to 600 km from its Ranshofen site with ease, which has opened up additional opportunities that would have been unthinkable when its liquid aluminium transport activities began. In this context, it is important to note that the company has maintained a consistent delivery reliability rate of 98% despite the increased logistical challenges. The next major step in the company’s development followed in 2014, when it began to supply liquid aluminum for automotive chassis and structural components.
Why liquid aluminium?
The current debates surrounding reductions in CO2 emissions highlight the advantages of liquid aluminium more than ever before. Supplying the metal in liquid form (Figure 4) presents a number of customer benefits, including significant savings in terms of metal losses, energy costs and logistics expenditure, as it removes the need for further energy use in remelting and eliminates the storage costs for sows. In addition, liquid aluminium facilitates targeted adjustments to customer requirements at short notice, which leads to increased productivity while cutting costs. AMAG also offers its customers the requisite technical and logistical expertise in this area to ensure that customers receive only high-quality primary material. By drawing on our years of experience, we have been able to implement suitable solutions for wide-ranging customer requirements.With this in mind, AMAG will this year invest in additional hot-holding stations, including crucibles. This will increase our capacities, enhance our flexibility and thereby enable us to respond even more swiftly to customer requirements.
Focusing on specialty products
As mentioned previously, aluminium recycling has been the economic basis of AMAG since the early 1990s. For a long time, secondary cast alloys based on the Al-Si alloy system were regarded as having a high proportion of recycled material on condition that moderate levels of elements such as Fe, Cu and Zn were permitted. AMAG began to investigate the effect of alloying elements on casting technology and mechanical characteristics at a very early stage. AlSi9Cu3 (A226) is considered an alloying sink, meaning that scrap containing too many elements can be processed into the secondary cast alloy A226 due to the wide alloying tolerances of the individual elements. This alloy is used in an array of applications, in particular in the context of combustion engines.Aluminium has a long tradition in automotive construction and will remain hugely significant in the future. A number of forecasts have predicted a sharp increase in the volume of aluminium required per vehicle due to the rise of e-mobility. This presents additional opportunities in relation to cast products, which AMAG has increasingly sought to exploit in recent years. A clear trend identifiable among AMAG customers is the increased use of die casting for larger components - a technique known as “megacasting” - to produce complex assemblies in a single casting rather than as 50 individual components. This has led AMAG to intensify its efforts to adapt primary alloys to contain higher levels of Fe, Cu and Zn. This is considered an ambitious goal. Components made from primary and near-primary alloys must have high ductility, sufficiently high dynamic characteristics and, as a result, high crash energy absorption. High corrosion resistance in all forms is also a very important factor. AMAG has therefore set itself the objective of developing near-primary alloys tailored to its customers’ requirements.
While mechanical characteristics are still a key factor when selecting a suitable alloy for a given component, resource conservation, sustainability, life cycle assessments and carbon footprints have become increasingly important considerations. AMAG believes that the only way to meet all of these competing requirements is by maximizing the recyclate content in alloys and relying on state-of-the-art smelting technology. Achieving the levels of recyclate demanded by our customers will require increasingly sophisticated recycling techniques. This is why AMAG has invested heavily in new scrap sorting and separation methods in recent years and continuously adapted its smelting systems to handle contaminated scrap. Another important aspect in this context is understanding the impact of impurities in scrap destined for recycling, as efforts to maximize scrap utilization are often at odds with limits on accompanying elements in customers’ specifications. Combining materials science and recycling techniques is therefore a crucial aspect in the future reuse of aluminium scrap. Furthermore, the EU places limits on the content of different elements in alloys through existing and impending substance bans. The full - albeit delayed - impact of this issue will be particularly evident in relation to old (post-consumer) scrap. It is therefore vital that we find ways to recycle the accompanying substances previously accepted in higher concentrations in alloys. Lead is one such substance.In addition to modern smelting and casting technologies, scrap separation technologies are also becoming increasingly important in the context of aluminium recycling. For example, AMAG has made significant progress towards sustainable manufacturing by developing and introducing a sensor-based sorting system in combination with increased use of mixed scrap. These approaches complement established sorting steps such as shredding and magnetic separation. The use of technologies such as X-ray transmission (XRT - Figure 5) and laser-induced breakdown spectroscopy (LIBS - Figure 6) enables AMAG to introduce scrap into the recycling process in a targeted manner. LIBS sorting technology in particular makes it possible to sort mixed scrap into different alloy classes.Die-cast light metal components will become even more important as the transition to e-mobility continues. While they were originally installed only in vehicles in a premium prize bracket, die-cast structural components (including suspension strut mounts, longitudinal and cross members, and various chassis components) are now increasingly found in mid-range vehicles. AMAG has already recorded impressive achievements in recent years and increased potential scrap utilization by making considered, targeted adjustments to alloy composition. These changes have improved the carbon footprint of its products without ever losing sight of customers’ component-specific requirements (see AluReport 02/2022).AMAG has thereby more than doubled the quantity of customized “special alloys” it produces over the last decade thanks to close collaboration with its customers. Demand for new products and applications will remain high in the future. In this context, it is important to bear in mind that each component places different demands on cast alloys. The highly skilled team at the Center for Material Innovation is tackling the challenge of advising customers even in the development stage for cast alloys to help them seize the manifold benefits of aluminium as a material.
