9th ECCC European Continuous Casting Conference – ECCC 2017

Macro-segregation in the center of CC strands can lead to problems during downstream treatment and application of steel. Particularly high carbon or high manganese steel grades are susceptible to form those high concentration areas concerning their pronounced heterogeneous structure during final solidification. Many investigations have carried-out during the past decades to determine those segregations quantitatively. Since the extension of segregated zones is in the scale of 10-3 m and modern CC machines produce nearly dense as-cast structures in the center without big pores like in early days, measuring techniques such as OES, drill-sampling or micro-probe analysis with electron beams are too coarse or too fine to reach sufficient results in a short time. The MAXILA process (Macro-Segregation Identifier by LIBS-Analysis) analyses sample areas, which cover several dendrite arms so that micro-segregation is averaged, and also segregated spots between equiaxed dendrites or V-channels can be identified. This contribution presents the LIBS based semi-automatic analysis system, which has been developed at the Department of Ferrous Metallurgy of RWTH Aachen University. Furthermore, results of high carbon steel strand investigations are presented and discussed. Keywords: Macro-segregation, analysis, as-cast structure, LIBS, MAXILA