Transport Phenomena - Delft University of Technology

Bernhard Righolt

Bernhard Righolt

Improved continuous steel casting by electromagnetic flow control

Contact details

  • Ir. Bernhard Righolt
  • Delft University of Technology, TNW-TP
  • Room: none
  • van der Maasweg 9, Delft, The Netherlands
  • b.w.righolt@tudelft.nl

Research interests

  • Magnetohydrodynamics
  • Free surface flow
  • Turbulence
  • Turbulence modelling

Social Media

Latest publications

  • Marangoni Driven Turbulence in High Energy Surface Melting Processes, Anton Kidess, Sasa Kenjeres, Bernhard W. Righolt, and Chris R. Kleijn. International Journal of Thermal Sciences 2016, 104 , 412–422.
    [Full Details]     [BibTeX]     Publisher: [DOI] 
  • Analytical Solutions of One-Way Coupled Magnetohydrodynamic Free Surface Flow, B. W. Righolt, S. Kenjeres, R. Kalter, M. J. Tummers, and C. R. Kleijn. Applied Mathematical Modelling 2016, 40  (4), 2577–2592.
    [Full Details]     [BibTeX]     Publisher: [DOI] 
  • Dynamics of an Oscillating Turbulent Jet in a Confined Cavity, B. W. Righolt, S. Kenjeres, R. Kalter, M. J. Tummers, and C. R. Kleijn. Physics of Fluids 2015, 27  (9), 095107.
    [Full Details]     [BibTeX]     Publisher: [DOI] 
  • Aspect Ratio Effects on Fluid Flow Fluctuations in Rectangular Cavities, Rudi Kalter, Mark J. Tummers, Jeroen B. Wefers Bettink, Bernhard W. Righolt, Sasa Kenjeres, and Chris R. Kleijn. Metallurgical and Materials Transactions B-Process Metallurgy and Materials Processing Science 2014, 45  (6), 2186–2193.
    [Full Details]     [BibTeX]     Publisher: [DOI] 
  • Effects of Electromagnetic Forcing on Self-Sustained Jet Oscillations, R. Kalter, M. J. Tummers, S. Kenjeres, B. W. Righolt, and C. R. Kleijn. Physics of Fluids 2014, 26  (6), 065101.
    [Full Details]     [BibTeX]     Publisher: [DOI] 

Education

  • MSc - Applied Physics Delft University of Technology (2010)
  • BSc - Applied Physics Delft University of Technology (2008)

Supervisors

Research description

Summary

In the last decade the world steel production was nearly doubled from 0.85 10^9 metric tons in 2001 to 1.42 10^9 metric tons in 2010. While the Dutch steel production, solely due to the Tata Steel (formerly Corus) plant in IJmuiden, is increased by 10% in this period, the production rate in China exploded with a 300% growth in this period (World Steel Association, 2011). The European steel market is still recovering from the economic crisis in 2008 and not yet back on the production rate of 2007.

The casting of metal in the beginning of the twentieth century was a batch process, casting the liquid metals in blocks. Already in 1887, the first idea for a continuous caster was patented (Abbel, 2000). The basic concept never changed. The vertical, water cooled mould, was filled with metal and the solidified metal was extracted and cut at the bottom. By the middle of the twentieth century this method was used and further developed, mostly for copper and aluminium casting.

Steel casting was more difficult since the melting temperature is relatively high (~ 1500℃) and the solidification is slow, because of the low thermal conductivity. Innovations as

  • the oscillating mould (1949) with negative strip time2 (1954),
  • the casting machine to bend the steel strip with a liquid core into a horizontal position (1963),
  • the submerged pipe to prevent nitrogen pick-up and re-oxidation (1965),
  • the tundish and rotating tower (1968) (solving the problem of the liquid steel arriving at the caster in
  • batches) and
  • the electromagnetic brake (early 80s)

were improvements that helped improving the efficiency and quality of the produced steel. This first EMBr was installed at Kawasaki and this EMBr helps increasing the production rate and quality of steel for several reasons.

Electromagnetic brake

Imposing an electromagnetic brake on the flow of liquid steel has been a great improvement in the steel casting process. The operation of the EMBr is explained by the magnetic field interacting with the conductive steel, generating a Lorentz force on the bulk of the steel inside the mould, which slows it down. The EMBr has a positive effect on the eventual quality of the steel. First, the meniscus will be hotter and more quiescent. This will prevent the meniscus from freezing and this will prevent inclusions of slag or air bubbles to be entrained. This will result in evenly solidified steel, improving the strength of the steel and not changing the desired composition of the steel. Second, the jet of the submerged pipe will not hit the solidified shell at the small side wall of the caster, preventing the shell from breaking or rupturing. Breaking of the shell is a horror scenario, since it causes a very unsafe scenario and the production process has to be interrupted for a longer period of time. If the shell does not brake, but is only damaged, it will be visible in the final steel product, degrading its quality. Third, the flow will penetrate less far into the strand, which reduces the depth to which inclusions can be dragged into the steel.

What do we do?

At our section in Delft, we are both working on experiments (see my collegue Rudi Kalter) and numerical simulations. In numerical simulations, we are discretizing the equations that describe transport of mass, transport of momentum, development of the electric current throught the domain, the location of the interface and the transport of heat. Validation against the experimental results will eventually provide a validated numerical model to predict the turbulent behaviour of the interface of cooling steel under the influence of a electromagnetic brake. This model will be used by our industrial partners, Tata Steel Europe and ABB.

This project is funded by STW.

Interested? If you are looking for a MSc or BSc project in this field, you can always drop by my office or send me an email at b.w.righolt@TUDelft.nl

Last modified: June 22 2016. © Delft University of Technology - TP group 2012