Aluminium materials: The major winner in competitive lightweight construction

Structocast: Intergrated development services for manufacturers of structural cast components

24. January 2018 | Engineering Service

The issue of lightweight construction is becoming more important in all areas of the automobile industry. In future car body construction, aluminum materials are going to be the major winner in competitive lightweight construction. According to current studies, the percentage of aluminum materials in car body construction will more than triple by 2025 and cover almost 20% of the average body shell weight. In higher-quality SUVs and in the premium vehicle class, more than 30% – roughly 100 kg to 130 kg – of the body shell will be made of aluminum. In principle, it follows that the smaller and more inexpensive the vehicle class is, the lower the percentage of aluminum in the car shell of the future. In very inexpensive vehicles, aluminum will continue to be of little significance. However, in sports cars and especially in electric cars (EV), the percentage of aluminum is considerably higher and frequently covers up to 100% of the material added value.

On the one hand, the folding process (especially hoods and doors) will soon be used in aluminum sheet metal shell construction; on the other, highly integrative structural cast components will soon dominate in mass-produced vehicles where once mostly steel construction approaches prevailed.

Structural Casting Gains Ground

The production of structural cast components is expected to triple by 2025. Structural casting is used increasingly in strut supports, as well as in heavily integrated node areas of car bodies. This development is creating a major challenge for the casting industry in meeting the heavily rising demand for “crash-suitable,” highly complex and joinable (welding, punch riveting, etc.) cast structures. Especially if the powertrain is heavily electrified, Tier1 suppliers, who have thus far been producing combustion engine components, must now expand their product portfolios and areas of expertise to be able to participate in this high-growth market. In addition, OEMs are increasingly expected to have more comprehensive expertise in order to minimize interfaces in the development process and to cover new developments from a single source. The creation of high performance, economical structural cast components requires an in-depth understanding of vehicle function development, materials potential, all process parameters during the casting process, as well as the downstream production steps. Today, the ability to understand the very complex interdependencies of these disciplines represents a major challenge.



Structrocast: Competent Development Portfolio for Tier1 Suppliers and OEMs

The joint venture company “Structocast” offers a solution to this by delivering a competent development portfolio for Tier1 suppliers as well as internal OEM casting companies. As needed, its support covers the entire process chain seamlessly – from the first concept drawings and the entire component configuration throughout the overall vehicle to casting process simulations and the production of test-ready prototypes in representative prototype processes, i.e. those transferable for serial validation in low-pressure casting. Current and future processes and developments in all sectors will be adequately represented.
Structocast is a joint venture between several companies that have strong expertise in complementary industries that support structural casting. Companies involved in this joint venture include Imperia GmbH (car body concepts and structural design), Magma GmbH (casting process simulation), Grunewald GmbH & Co. KG (prototypes and tool manufacturing) and the Gießerei-Institut der RWTH Aachen [Foundry Institute at RWTH Aachen] (metallurgical testing and future trends).
The casting expertise covers all relevant aspects of the process for car body design and construction.


The Structocast partners and their tasks

Imperia’s Areas of Competence

Imperia plays a critical role in concept development all the way up to the finished functional configuration of the structural casting components. Backed by a complete understanding of the entire car body development process, the specialist company is able to identify the perfect application areas and requirements for structural casting and to work efficiently with the partners specified to develop a powerful, lightweight structure that is casting-friendly. Efficient development always involves the timely consideration of process-related restrictions and production-end influences on manufacturability and component performance. This includes taking into account the unavoidable formation of casting inhomogeneities as well as process-related influences on the material properties that can impact fracture elongation and resistance in the crash and resistance simulation.

Simulating the casting process as well as component function is becoming more important for two reasons: First, aluminum casting is a very complex process in which the structural properties are influenced by a multitude of factors. Secondly, the requirements for the forecasting quality for crash and resistance-related structural areas of a car body are increasing.
Another important area of competence is the simulation of mass-produced structural cast components produced in a vacuum-supported pressure casting system. To increase efficiency, a technical test validation is performed using inexpensive, quickly produced sand casting prototypes. All this has to be represented in a closed numeric process chain in order to meet the increasingly shorter development cycles.



Ensuring Decisive Market Advantages

In principle, it has been determined that development time and effort is concentrated in the early development phases. At the same time, development and optimization loops must be considerably reduced in the later course of the project. This is the only way to ultimately reduce development time and costs sustainably and to ensure that excess weight is removed from areas of the structure where it is not needed according to the mechanical requirements.

Casting customers can opt for a “one-stop shop” solution for the entire configuration of a structural casting component or, instead, selectively, for services from the individual Structocast partners. Either way, the customer can assume that the team has understood the complex requirements of structural casting production and will deliver services to its decisive market advantage. For all developments of this kind, Structocast is the perfect partner not only for current project business, but also for developing new competencies with high-level and comprehensive expertise.


Process chain of Structocast