Aluminium makes chromium-nickel steels lighter, stronger and more resistant to corrosion

How can chromium-nickel steels be made lighter and stronger, and at the same time more sustainable? A research project at the University of Kassel and the TU Bergakademie Freiberg is investigating the impact that the precisely dosed addition of aluminium has on the properties of steel – and how this could result in a material for the future.

“Rustproof steel – commonly referred to as stainless steel – is an integral part of our everyday lives, be it as kitchen cutlery, as a component in cars or for use in high-tech applications. The aim of my doctorate is to further develop the material so that it meets increasing demands for sustainability and resource efficiency,” says welding engineer Steffen Scherbring, a research assistant and doctoral student at Osnabrück University of Applied Sciences, Germany.

Why choose aluminium?

While aluminium is normally only used in steelmaking to bind oxygen (deoxidation), the doctoral thesis investigates its use as a permanent alloying component. Initial results demonstrate that adding five per cent aluminium makes the steel not only lighter and stronger, but also more resistant to corrosion. It also has good welding and better wear characteristics. Adding aluminium also enhances steel’s scrap compatibility, which means using a higher proportion of recycled material in steel production without compromising on quality. That is a crucial factor in sustainable recycling processes.

Challenges in production

“Although these positive properties are already known, the use of aluminium in these quantities has been barely tested to date,” Scherbring says. “Why is that? Aluminium reacts rapidly when it comes into contact with oxygen – a risk that was previously considered too high in industrial steel production.” For this reason, processing is currently being tested in various application projects in conjunction with industry partners. This includes products that are exposed to high abrasion at high temperatures such as in waste incineration plants or hydrogen production.
Source: Hochschule Osnabrück