Developed at Hydro’s innovation and technology center 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.

“In addition to cost and weight reductions, this alloy can help carmakers improve passenger safety in the vehicle,” says Nunzio Cuppoletta, automotive market director for Hydro’s business area Extruded Solutions.

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 percent 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 center in Finspång, Sweden, 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, the frame of the car, 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, such as front bumpers. According to Cuppoletta, the new alloy can also be used in non-automotive applications.

“These would mainly be applications where we are competing with steel, because you lose ductility and formability (elongation) with the new alloy, compared with other aluminium alloys,” he says.

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.

Developing alloys for all industries

Hydro is consistently working to develop new alloys to meet the needs of customers in all industries. This includes the 5083 aluminium alloy for marine and offshore applications.

The new HHS 400 aluminium alloy compares well against 7xxx-series alloys in terms of:

• Price
• Handling
• Welding
• Productivity
• Availability

HHS 400 is also a possible substitute for steel and for other existing 6xxx-series aluminium alloys, with its strength enabling thinner-walled solutions.