‘Real steel’ but takes 90 per cent less energy to make

Associate Professor Nikki Stanford with an electron microscope, which is used to analyse samples of steel. SCIENCE AND TECHNOLOGY
Associate Professor Nikki Stanford with an electron microscope, which is used to analyse samples of steel.

Steel can be made using 90 per cent less energy than in the most common production process, but very few companies are pursuing this more environmentally-friendly method because the science behind it has not been well understood.

But Associate Research Professor with the Future Industries Institute (FII) Nikki Stanford is changing that through research that explains the exact behaviour of steel made using thin strip casting.

The method involves turning liquid steel directly into thin strips up to 3mm thick, rather than the traditional process which involves steel casting, hot and cold rolling (including reheating), coil coating and strip processing.

“This new method of thin strip casting was originally developed in Australia but is only used by two plants in the USA and reduces the energy consumption involved in turning liquid into thin steel by 90 per cent,” Assoc Prof Stanford says.

A gigatonne of steel sheeting (1000 million tonnes) is made every year for use in roofing, fencing, car doors and general construction – and that figure is growing.

“So if we can change to this new method, it’s a massive environmental benefit,” Assoc Prof Stanford says.

While the traditional process, of repeatedly forging and rolling steel into the required shape, is well understood, the same cannot be said of the thin strip casting method. In strip casting, the steel is cast between two water-cooled rolls, producing directly a strip. This results in very rapid cooling and high production speeds.

“We need to expand the kinds of alloys that can be made using this process,” Assoc Prof Stanford says. “What happens in this process is that the steel goes solid really quickly and behaves strangely so it’s more difficult to make in this way.

“You have to make it with enough speed at the exact right rate, at the exact right time, so that the steel doesn’t harden and break the caster. It requires very stringent process control.

“The work we are doing explains what occurs and why – how the alloy chemistry changes the outcome. At present, the outcome is not predictable.”

However, even once the research findings are published, it will be a slow process to encourage more manufacturers to adopt the strip casting method because steel plants have 50-year or longer life cycles.

The strip casting method can also make stronger steel, requiring less steel in finished products, reducing weight and associated costs.

Assoc Prof Stanford was appointed as part of a new $2m fellowship program aiming to increase the number of female researchers in UniSA’s Future Industries Institute. In partnership with UniSA and University College London's (UCL) Faculty of Engineering, Santos has provided $2 million to fund the research fellowships.

“It’s a great opportunity to do something with impact – my research has always been very practical,” Assoc Prof Stanford says. “And it’s also an opportunity to do new things with new people and to apply my skills to other people’s projects.”

The fellowship program also supports UniSA’s role in Australia’s Science in Australia Gender Equity (SAGE) project. Modelled on the UK’s Athena Swann Charter, SAGE is a partnership between the Australian Academy of Science and the Australian Academy of Technological Sciences and Engineering, to address the systemic barriers to women’s career advancement.