Delta-Heat: Saving steel and reducing CO2 by simply applying coatings

The company Dörken MKS-Systeme GmbH & Co. KG and their partners have developed high-temperature corrosion protection for high and super-alloy steels. What is special about Delta-Heat®: the coating reduces scale formation, which occurs during steel processing, by up to 80 per cent. This produces significantly fewer rejects and fewer CO2 emissions.

Every year 36.6 million tonnes of hot-rolled steel and plate are produced in Germany. This creates 915,000 tonnes of mill scale – wasted material. Scale is formed on the surface of the steel as an oxidation product during the hot forming process in the rolling mill; it is a layer that can be several millimetres thick, which must be removed using an expensive process. If that is not successful, the defective areas have to be discarded. In a joint research project with the VDEh-Betriebsforschungsinstitut GmbH (the Department of Applied Research of the Steel Institute VDEh) and the rolling mills Walzwerke Einsal GmbH, the company Dörken MKS-Systeme in Herdecke has developed a coating system which can reduce scale formation by up to 80 per cent.

Engine for progress:

  • savings of over 500 tonnes of material and 750 tonnes of CO2 in a medium-sized rolling mill
  • simple and practical application
  • water-based coating, ecologically harmless
  • application also possible to pre-corroded steel

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Dörken MKS

Improved quality, less reprocessing and less rejects, other improvements in processes – a lot of good arguments for rolling mills, excellent prerequisites for diffusion of the technology and also for climate protection.

Efficient and environmentally friendly

From the start of the project, it was of prime importance to avoid solvents, volatile monomers, toxic additives and external energy sources such as curing ovens. The “paint” is water-based and its main constituents are aluminium platelets (< 1 µm thick) and a siloxane-based polymer.

The new coating forms a 10-20 µm thin layer on the surface of the steel and is stable for up to 60 minutes at a temperature of over 1,000 °C. Since it is resistant to weathering, the treated products can be stored in the open air. The surface is less rough and has fewer defects and this improves the quality of the product. Material loss and the reject rate are reduced.

Higher quality

It is not possible to completely prevent scale formation, however. Nevertheless, using this new process the scale layer is thinner and smoother and thus does not interfere with subsequent processes such as heat treatment, forming and straightening. The paint can even be applied to pre-corroded steel. The amount of scale produced in a medium-sized mill is around 700 tonnes per year; the reject rate is up to 20 per cent. With the help of this new coating system, a massive amount of material can be saved. The reduction in the level of CO2 emissions equates to about 750 tonnes.

Dörken MKS

"DELTA-HEAT® is a perfect example of innovative networking in Germany: targeted promotion of practice-oriented projects involving universities, medium-sized companies and industry, resulting in a unique new technology for conserving resources which is competitive on an international scale."

Dr Marcel Roth, Head of Research and Development, Dörken MKS-Systeme GmbH & Co. KG

"DELTA-HEAT® allows us to offer our clients a technology which achieves maximum savings in the area of metal processing at very high temperatures using the thinnest of coatings."

Sandra Böhm, Team Leader Basecoats, Dörken MKS-Systeme GmbH & Co. KG

Partners and sponsors

  • Dörken MKS-Systeme GmbH & Co. KG
  • Betriebsforschungsinstitut VDEh-Institut für angewandte Forschung GmbH
  • Walzwerke Einsal GmbH
Counselling centers:
  • Effizienz-Agentur NRW (EFA)