Soft Reduction at a Round Bloom Caster: Implementation and Results

Abstract

As a consequence of steadily increasing demands on the control of macro segregation in high quality steel products, voestalpine Stahl Donawitz GmbH started investigations on the application of the soft reduction technique for the five strand round bloom caster CC3. Between the years 2006 and 2010, a broad variety of different plant trials with steel grades ranging from 0.8 to 1.05 %C were conducted. The experiments started with the given pinch roll configuration at the pilot strand number one and finally provided a wide understanding of the influence of soft reduction on the solidification structure and on the concentration level in the core region. As a part of this project, a time and cost efficient method for the quantification of the center segregation was established. In addition, numerous segregation values were collected along the entire process route, from bloom to wire. As a consequence of the outstanding results, all five strands were equipped with a soft reduction unit in 2010.