BMW April 2022

Material research from Hydro has led to the development of a new high-performing aluminium alloy for applications that require high-strength aluminium solutions. The alloy will be particularly useful for next-generation cars, where weight and cost reductions are the key drivers.

Developed at Hydro’s innovation and technology centre in Finspång, Sweden, the Hydro High Strength 400 aluminium alloy (HHS 400) is unique to the automotive industry and now available for original equipment manufacturer (OEM) qualifications.

High-strength aluminium solutions are important as the automotive industry uses light metals in greater quantities to build safer and more durable vehicles, specifically to meet stricter fuel efficiency regulations. Aluminium also provides considerable weight savings compared to steel components, and aluminium extrusions can absorb twice the amount of crash-induced energy as the heavier metal.

“Sustainability is a key benefit. OEMs are evaluating uni-alloy concepts – and combining 6xxx with 7xxx-series aluminium alloys lowers the scrap value of the car. This is a good alternative to 7xxx-series alloys,” says Cuppoletta.

Tensile strengths unique in the market

Industrial verifications have confirmed the results of lab trials that the new alloy achieves yield strengths above 370 megapascals (MPa), ultimate tensile strengths greater than 400 MPa, and elongation at A5 of 8% on sections ranging from mean thickness substantially lower than 3 mm.  Standard 6xxx alloys on the market today typically do not exceed tensile yield strengths above 320-330 MPa.

Last year, legacy Sapa – now part of Hydro – launched a high-strength 6xxx-series aluminium alloy (HHS 360) that provides yield strength above 340 MPa and 10 percent elongation. But according to Susanne Koch, metallurgical engineer at Hydro’s innovation and technology centre, the step up from this alloy to the new HHS 400 alloy is a much bigger step.

“This is part of a bigger initiative in high-performing high-strength alloys based on the 6082. We can take the standard 6082 to MPa of 320-340. As a premium product with very high mechanical properties, it finds the right balance between advancements in technology with improved cost performance,” says Koch.

Targeting the vehicle chassis segment

The vehicle chassis is a main segment for HHS 400. Applications would include anti-vibration components such as engine mounts, side members for doors and crash management systems, and even front bumpers.

According to Cuppoletta, HHS400 is most suitable for non-formed applications. It can also be used in chassis or structural components for trucks or buses, and in electric cars, for instance, with side members to protect the battery.