Classification of non-metallic inclusions

Task definition

  • To determine the chemical composition of submicroscopic, non-metallic inclusions (NMI) in steel, analysis using a scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS) is widely used (resolution limit approx. 200-300 nm)

  • However, since information about the chemical composition can also be derived from the backscattered electron (BSE) detector image of the SEM or the particle shape, it was investigated to what extent machine learning (ML) can be used for purely image-based classification without relying on complex EDS measurements

Realization

  • Data set: BSE images of the NMI, with associated ground truth is determined from the EDS spectrum
  • Use of Deep Learning (DL): classification model based only on the BSE images
  • In this application example, 5 classes are considered: Carbonitrides, oxides, sulphides, mixed oxide-sulphides as well as “non-inclusions” (e.g. pores, scratches, contaminations)

BSE recordings of the 5 classes

Results:

  • The DL model achieved an 84.9% accuracy in determining the chemical composition of the NMI using only the BSE image

  • Specifically, carbonitrides, sulphides and “non-inclusions” can reliably be classified

Fields of application

  • Time saving by substituting EDS measurement with pure image evaluation

Cooperation partners

  • Aktien-Gesellschaft der Dillinger Hüttenwerke, Dillingen/Saar
  • Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh

Contact for questions

Dr.-Ing. Dominik Britz

Deputy Head MECS Saarbrücken

+49 681 302 70540
d.britz@mec-s.de
LinkedIn

Tobias Fox

Dr.-Ing. Tobias Fox

Chief Operating Officer

+49 157 52210561
t.fox@mec-s.de
LinkedIn

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