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Clean steel

At the Unit of Processes, one of our main areas of focus is the improvement of cleanliness in steels. That means removing contaminants and preventing the production of unwanted particles in the steel during processing. This will improve capabilities of steel and reduce wastage, both of which provide a direct contribution to sustainable development.


Materials processing involves the knowledge of industrial processes, reaction thermodynamics, reaction kinetics and transport phenomena. In view of the heterogeneous reaction nature of most of the processes, it also needs the research of the interfacial phenomena. At the Unit of Processes, we have knowledge and well-documented expertise in all these areas. We have been the institution with the most presentations in ten separate clean steel conferences and one of our articles has been dowloaded over twenty thousand times (Ånmark, N., Karasev, A., & Jönsson, P. G. (2015). The effect of different non-metallic inclusions on the machinability of steels. Materials, 8(2), 751-783 DOI: 10.3390/ma8020751, available via open access from the homepage of the journal Materials ). Overall, our work in clean steelss has been shared with industry and the scientific community through journal articles (204), PhD theses (61) and lifelong learning.

Clean steel has superior properties and a longer lifetime than impure material. It minimises costs, environmental impact and resource consumption.

Within our studies on clean steel, the Unit of Process has expertise and facilities to support the study of:

  • carbon direct avoidance
    • e.g. hydrogen-based reduction of iron ore to metal
    • switching from electric arc technology (incorporating graphite electrodes) to plasma-based furnaces
  • smart carbon usage via process integration
    • the use of biofuels in steelmaking to reduce dependence on fossil-derived carbon
  • circular economy
    • recycling of byproducts from various industries to provide feedstock for steel making
      • steelmaking slags as neutralising agents
      • waste from the forestry industry to provide fuel for steelmaking
      • waste from the paper and pulp industry to provide calcifying agents and fuel
  • combination of pathways
  • enablers and support actions

Carbon-free ironmaking

  • Hybrit
  • Ironarc

Smart carobn usage with process integration

  • Biofuel
    • Biooil
    • Biogas
    • Forestry waste

Circular conomy

  • Slag reuse as neutralising agent
  • Paper and pulp reuse

Work in the area of circular economy and recycling has been shared between KTH, industry and the scientific community through journal articles (101), book chapters (4), PhD theses (15), licentiate theses (2) and lifelong learning.

Non-metallic inclusion analysis

One specialist technique used by the Unit of Process is electrolytic extraction of non-metallic inclusions from steels, together with scanning electron microscopy. This allows investigation of the inclusion in three dimensions and can overcome some of the limitations with two-dimensional investigation on polished samples. Investigations have been performed on inclusions such as alumina, magnesia, calcia, zirconia, rare earth metal oxides, oxy-sulfides and various nitrides and carbides. The Unit of Processes is one of the centres that is most active with this method. We have reported this technique in 30 academic publications and 35 conference presentations since 2008.


Belongs to: Materials Science and Engineering
Last changed: Apr 15, 2021