Effect of Coiling Operation on Strip Quality of 4.5% Si Steel in Twin-roll Casting Process
Rapid solidification in the twin-roll casting process allows the production of thin strip with a unique combination of properties, directly from the melt. However, the production of the thin strip without any intermediate technological processing, is accompanied by strong demands on quality of the as-cast strip and requires full understanding of all aspects of twin-roll casting technology. <br>The present study was aimed at an experimental analysis of the influence of continuous coiling in the twin-roll casting process on structure, properties and the shape of as-cast high silicon electrical steel strip. It was found that solidification, cooling and plastic deformation produce high residual stress heterogeneity in the as-cast strip which exists in a non-equilibrium state. When the compressive residual stress, attains a critical value the strip loses its flatness and waviness of a sinusoidal shape appears on the surface in the casting direction. When the tensile residual stress reaches the yield strength of the casting materials, cracks may be appear in the strip.<br> The use of continuous coiling at elevated temperatures and with the as-cast strip under tension, leads to a change in structure, properties, geometry and shape of the as-cast strip. The structure and properties can be effectively controlled by regulating the temperature of the coiled strip and the shape can be controlled by regulation of the strip tension.<br> The use of optimal temperature and strip tension during the continuous coiling operation are effective control strategies for stabilising structure, properties, and shape of the as-cast strip, reducing the residual stresses in the strip and improving its quality.
- ISIJ international
ISIJ international 39(5), 463-470, 1999-05-15
The Iron and Steel Institute of Japan