Optimization of the Two‐ and Three‐Dimensional Characterization of Rare Earth‐Traced Deoxidation Products

Abstract

Tracing by means of the light rare earths (REs), particularly La and Ce, is a state‐of‐the‐art method used to track deoxidation products during the steelmaking process. Traced heterogeneous multiphase inclusions are analyzed using scanning electron microscopy with energy‐dispersive spectroscopy (SEM/EDS) to perform a 2D characterization. The sequential chemical extraction technique is implemented for a 3D investigation to determine traced particles’ actual sizes and shapes. The automated SEM/EDS measurement must be optimized since RE oxides appear brighter in the backscattered electron images due to their high atomic numbers. Therefore, two grayscales are implemented for the detection of RE‐containing multiphase inclusions. Within this technique, individual RE‐traced heterogeneous nonmetallic inclusions (NMIs) are counted as separate particles. Thus, the measured NMIs must be recombined, which is achieved using a self‐developed MATLAB tool. The extracted particles are also analyzed by automated and manual SEM/EDS measurements to determine the 3D morphologies and sizes of traced NMIs.

Tracing of Deoxidation Products in Ti‐Stabilized Interstitial Free Steels by La and Ce on an Industrial and Laboratory Scale

“…A software was developed to reassemble these particles into a single multiphase inclusion to address this issue. The principle of the recombination software has been previously published by Thiele et al [21] As mentioned earlier, the formed clogging layer structure within the used SEN was also examined in detail. For this purpose, a section from the central part of the straight area of each SEN was cut out using an angle grinder, which was then halved (Figure 5a).…”

“…A software was developed to reassemble these particles into a single multiphase inclusion to address this issue. The principle of the recombination software has been previously published by Thiele et al [ 21 ]…”