Investigation of mould powders and slags
The therefore applied methods are listed below:
- Reflected light and scanning electron microscope for mould powder, mould slags and samples annealed at selected temperatures (fig. 1 and fig. 2)
- Hot stage microscope (fig. 3 and fig. 4) for investigation of mould powders, polished sections of mould powder specimen, as well as mould slags at temperatures up to 1500°C
- Differential thermal analysis and thermogravimetry
- Investigations using the double hot thermocouple technique (DHTT) (fig. 5): There the crystallisation behaviour of a mould slag in dependence of the temperature gradient is observed.
- High temperature viscometer (fig. 6)
The characterisation of mould powders using the methods quoted above makes it possible to draw conclusions concerning operating performance and mould powder selection.
Fig. 2: Microstructure of a mould powder after annealing at 1000°C (scanning electron microscope, backscattered electron image); phases: cuspidine (1), feldspathoide (2), and glass phase (3) 
Fig. 3: Scanning electron microscope, backscattered electron image of a slag rim 
Fig. 4: Hot stage microscope 
Fig. 5: DHTT
Fig. 6: High temperature viscometer
 I. Marschall, H. Harmuth: “Investigation of the slag rim growth in the continuous casting process”, SCANMET III- 3rd International Conference on Process Development in Iron and Steelmaking, 8-11 June 2008, Luleå, Sweden
 N. Kölbl, H. Harmuth: „Hot stage microscopy for in situ observations of the melting and crystallisation behaviour of mould powders”, SCANMET III- 3rd International Conference on Process Development in Iron and Steelmaking, 8-11 June 2008, Luleå, Sweden
Contact: Nathalie Kölbl, Irmtraud Marschall