BIANNUAL REPORT 2018/19

Research Theme 7:
MAGNETOHYDRODYNAMIC
AND ELECTROCHEMICAL
PHENOMENA IN
REMELTING PROCESSES
A. Kharicha, E. Karimi-Sibaki, M. Wu, A. Ludwig
Aims and key objectives
• To understand the interaction between phase
distribution and magnetohydrodynamics
when strong electric currents are applied;
• To predict the electrical current path in the
presence of strong spatial and temporal
variation of electric conductivity;
• To solve process instabilities and predict the formation
of defects in the electroslag remelting process
(ESR) and vacuum arc remelting (VAR) process;
• To understand electrochemical apects of the
ESR process;
• To predict the thermal and solidification characteristics
during remelting of different metallic alloys;
• To explore the origin of the coherent arc
behaviour in the VAR process;
a
b
Figure 7:
(a) Melting during the electroslag remelting process (ESR) process and (b) cathode spots distribution during the vacuum
arc remelting (VAR) process. Red and yellow colours show a high electric current density. During ESR the formation of metal
droplets happens in a turbulent slag flow constantly heated by the strong electric current. In the figure the slag has been
masked out. During VAR the electric current is extremely localised inside the so-called cathode spots, which move rapidly over
the surface of the electrode.
18 Research Theme 7: Magnetohydrodynamic and Electrochemical Phenomena in Remelting Processes