Magnesium and the Rise of Semi-Solid Technology
In the quest for lighter, more efficient vehicles, magnesium alloys and semi-solid casting technologies, such as thixocasting and rheocasting, are becoming increasingly hot topics, especially in China. With the automotive sector under pressure to enhance performance while reducing weight, the convergence of these technologies offers both a challenge and a transformative opportunity.
Magnesium is the lightest structural metal available for mass production. At a density of just 1.74 grams per cubic centimeter, it significantly reduces the weight of vehicle components compared to aluminium or steel. Because China controls over 60% of the global magnesium supply, it is uniquely positioned to lead in this field.
In China, it is commonly utilized for vehicle interiors, including cross-car beams, brackets, and dashboard structures. It is also finding applications in chassis and structural parts such as wheels, battery enclosures, and motor housings. Furthermore, magnesium is being integrated into larger structural components to achieve lightweight efficiency in gigacastings.
China’s Edge in Semi-Solid Technology
Semi-solid casting is a manufacturing process that exists between traditional casting and forging. It involves partially solidifying the metal before injection, which allows for laminar flow and results in improved material properties. There are two main types of semi-solid casting:
Thixocasting uses a specially prepared billet that is reheated to a semi-solid state before being injected into the mould. Rheocasting, on the other hand, involves cooling liquid metal under controlled agitation to bring it to a semi-solid state.
The benefits of semi-solid casting are numerous. It offers improved mechanical properties, such as higher strength and reduced porosity. It also extends the life of the die by using lower injection forces and speeds, which reduces wear and tear on the tooling. Additionally, semi-solid casting enhances safety during the processing of magnesium, which is prone to oxidation and flammability at high temperatures.
Chinese companies are making strides in semi-solid casting technology. For example, Yizumi has developed an innovative method called SEED, which utilizes a high solid-phase fraction to produce castings. Additionally, Chinese researchers and software developers are incorporating artificial intelligence to optimize casting parameters, thereby reducing the need for trial and error in the development cycle.
Although semi-solid casting has been known since the 1970s, China is now leading the industrial-scale implementation of this technology. The upcoming China Die Casting fair will feature various demonstrators of thixocasting and rheocasting machines, particularly showcasing their applications with magnesium alloys.
Conclusion
As vehicle electrification and lightweight continue to shape the future of automotive manufacturing, the intersection of magnesium alloys and semi-solid casting technologies is gaining unprecedented momentum. With a vast resource base, rapid technological advancements, and a proactive innovation culture, China is poised to lead the next phase of casting innovation.
Share:
Casting Insights⚒️
Learn about new topics around the foundry industry each Tuesday.
Subscribe to the newsletter with your E-Mail and become part of the community.
