Twin Roll Casting and Secondary Cooling of 6.0 wt.% Silicon Steel
Abstract
:1. Introduction
2. Materials and Methods
2.1. Material Processing
2.2. Materials Characterization
3. Results and Discussion
3.1. The Casting Process
3.2. Segregation
3.3. Microstructure and Microtexture
3.4. Superlattice Structure
3.5. Rollability
4. Conclusions
- It was shown that a Fe–6.0Si alloy can in principle be processed by means of twin roll casting. In both trials, strips with a stable process point free of process oscillations could be produced.
- With the aid of the EPMA measurements, a largely homogeneous Si distribution was measured over 70% of the cross-section of the strip. Furthermore, no dendritic solidification could be observed. Nevertheless, microsegregations occur, especially in the center of the strip with maximum measured Si contents of 6.85 wt.%.
- The microstructure is refined by water-cooling, especially in the area close to the surface. However, too severe water-cooling induces thermal stresses in the sheet that lead to plastic deformations.
- Both cooling strategies led to a predominantly <001>//ND texture, which is desirable for electrical steels.
- The coexistence of B2 + DO3 structures was proven both in the air-cooled state and in the water-cooled and coiled state. However, a state far from equilibrium with finely distributed domains was set.
- Rollability at room temperature is poor and can be significantly improved by raising the rolling temperature to 500 °C. The maximum achievable sheet thickness before catastrophic failure was 0.5 mm by warm rolling.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
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Trial Number | C | Si | Mn | Al | P | S | N |
---|---|---|---|---|---|---|---|
unit | ppm | wt.% | wt.% | ppm | ppm | ppm | ppm |
method | CA | ICP-OES | S-OES | S-OES | S-OES | S-OES | TCA |
AC1378 | 56 | 6.04 | 0.06 | 40 | 46 | 48 | 30 |
AC1379 | 43 | 6.03 | 0.06 | 20 | 39 | 42 | 31 |
Trial Number | RSF (kN) | Strip Thickness (Mm) | Melt Superheat (°C) | Heat Flux Density (MW/m2) | Contact Time (s) | Roll Nip Exit Temperature (°C) | Secondary Cooling | Coiling Temperature (°C) |
---|---|---|---|---|---|---|---|---|
AC1378 | 10 | 1.7 | 50 | 6.4 | 0.45 | 1230 | Air | No coiling |
AC1379 | 10 | 1.7 | 80 | 7.9 | 0.39 | 1200 | Water/air | 700 |
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Müller, M.; Czempas, D.; Bailly, D.; Hirt, G. Twin Roll Casting and Secondary Cooling of 6.0 wt.% Silicon Steel. Metals 2021, 11, 1508. https://doi.org/10.3390/met11101508
Müller M, Czempas D, Bailly D, Hirt G. Twin Roll Casting and Secondary Cooling of 6.0 wt.% Silicon Steel. Metals. 2021; 11(10):1508. https://doi.org/10.3390/met11101508
Chicago/Turabian StyleMüller, Max, Dorothea Czempas, David Bailly, and Gerhard Hirt. 2021. "Twin Roll Casting and Secondary Cooling of 6.0 wt.% Silicon Steel" Metals 11, no. 10: 1508. https://doi.org/10.3390/met11101508