Novel alloy solution makes metallic materials endure corrosion six times longer
An innovative alloy and design process is currently upscaled within the EIT RawMaterials project Endureit to prolong the lifetime for duplex stainless steels. Results from an earlier project funded by EIT RawMaterials shows that the new alloy’s lifetime is about six times longer than the lifetime of conventional grades. Furthermore, the alloy solution significantly lowered the sensitivity towards intermediate temperatures.
Consequently, the outputs of this upscaling project will provide a more sustainable solution where materials will not has to be replaced as frequently. As the steel market is expanding, solutions like this are needed to enhance the competitiveness of the European industry.
We have developed an alloy that increases the lifetime of duplex stainless steel. Our solution brings a product with obvious advantages that can be used instantly by industry in several sectors. Traditionally, the material development processes in the industry are very time-consuming. Our solution will decrease the time spent on development and implementation of new materials from about 10-20 years to about 2-4 years.
Peter Hedström, Project leader and Professor in Material Science at the Swedish Royal Institute of Technology, KTH
Service temperature of about 100 °C
Duplex stainless steels have been around since the 1930s, and intermediate temperature embrittlement has been a problem since then. Until now, no one has been able to develop an alloy solution with significantly lower sensitivity towards intermediate temperatures.
Duplex stainless steels have an attractive combination of high strength and corrosion resistance, making them a suitable choice in applications within, for example, the nuclear-, chemical- and pulp and paper industry. To increase efficiency in these applications, higher service temperatures are needed.
Currently, the service temperature of duplex stainless steels is limited to about 250°C. Above this temperature, the material is embrittled. However, one of the aims of this project is to upscale an alloy solution that is less sensitive to intermediate temperature embrittlement.
Successful pilot plant
In the last decade, developments in experimental and computational tools have been significant. The two EIT RawMaterials’ partners the Swedish Royal Institute of Technology, KTH, and Outokumpu, have been very active in the field of intermediate temperature embrittlement of stainless steel, and in 2017, they launched a joint project funded by one of EIT RawMaterials’ Booster Calls.
”In Outokumpu we think this project is a success because we have had the opportunity to a very close collaboration with the highest technical university competences focusing on a for us very important and technical material issue.”
Jan Y Jonson, Senior Specialist in Physical Metallurgy, Outokumpu Stainless AB
The project consisted of KTH and the spin-off company HiMat Engineering AB in collaboration with Outokumpu AB. The aim was to investigate whether the new knowledge could be applied to design a new duplex stainless steel alloy with an estimated prolonged lifetime. The project was very successful, and the alloy was produced in pilot industrial scale by Outokumpu.
“The results were technically remarkable. Our next step is to fully validate the new alloy design methodology by upscaling the solution.”
Peter Hedström, Project leader and Professor in Material Science at the Swedish Royal Institute of Technology, KTH
Therefore, a consortium with additional expertise was founded and a new project named Endureit was initiated and funded by EIT RawMaterials (2019–2021). The project includes the research institute French Alternative Energies and Atomic Energy Commission, CEA, which focuses on nuclear power, and Haldor Topsoe, which specializes in the production of heterogeneous catalysts and the design of process plants based on catalytic processes. Haldor Topsoe will make their expertise available as an end-user of duplex stainless steels. Hence, the consortium is complete with the whole value chain represented.
