Will it bend or will it break?

‘The steel industry is facing major changes,’ says Francesco Maresca, a materials scientist at the University of Groningen. ‘We need to reinvent how we produce steel and how we use it.’ Together with Bart Kooi, Yutao Pei, and Jan Post, fellow materials scientists from the University of Groningen, Maresca is involved in the Growing with Green Steel project, which received 124 million euros from the National Growth Fund and another 53 million euros from private investments. The project will be executed by a large consortium of companies and universities, working towards a new, greener life cycle of steel.

FSE Science Newsroom | Charlotte Vlek

In Europe, we produce almost one kilo of new steel per person per day; all this steel goes into daily objects such as keys and paperclips, but also (medical) appliances, cars, and buildings. For years and years, steel was produced by heating iron ore and coke (coal) together. This process extracts oxygen from iron ore, with CO₂ as a by-product, making the steel industry one of the largest industrial polluters worldwide.

There is an alternative; using hydrogen (H₂) instead of coal would produce water (steam) as a by-product. Better for nature, and better for residents who live near factories. But a different production process will also affect the material properties of this green steel.

Same composition, different material

‘With the same chemical composition, a material can have different properties, depending on the atomic structure,’ Bart Kooi explains. ‘Steel is, in that regard, a complicated material.’ Maresca adds: ‘Compare it to cooking pasta. The same brand of pasta can become gluey or crunchy, depending on how you cook it. It ultimately comes down to the microstructure of the material, how the molecules bond in the process of cooking.’

That’s why the researchers involved in this project will use a powerful combination of experimental, fundamental, and applied research to figure out the best way of ‘cooking’ environmentally friendly steel. This should lead to models that can predict and optimize the material properties of green steel.

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Observing and modelling

The production of the green steel will take place in the laboratories of Tata Steel Netherlands or at Alleima Sweden. Afterwards, the researchers at the UG will get to work. With his electron microscopes, Bart Kooi can look at the atomic structure of the material. Using this information, Francesco Maresca will develop computer models of the material’s microstructure, which in turn will be checked against new observations under the microscope.

Combined, these models and observations can predict what kind of properties the material will have. How strong will it be? How much plasticity will it have? Will it bend or break when put under a lot of stress?

Engineering and predicting

The treatment to make steel corrosion resistant also affects its material properties. Adding a protective coating involves submerging the steel in a hot bath of zinc, thus heating the material. Yutao Pei will work at developing new coatings and coating technology. He will work closely with Bart Kooi and Francesco Maresca, who will keep checking whether the coatings preserve the steel’s desired microstructure.

Jan Post, working at the University of Groningen and at Philips Drachten, is responsible for the user-phase of the entire consortium. Together with other institutions and private companies, he will develop predictive models for specific applications, building on the observations and computer models of Kooi and Maresca. Posts’s models will help to predict how a razor made out of a new type of green steel will keep after intensive use, or a car. Or how long steel bearings of a wind turbine will last, or a landing gear of an airplane.