Morphological and analytical characterization of inclusions: Relation with processing parameters and properties of use

Nature, density, and morphology of inclusions in steel depend on processing parameters and have a strong influence on properties of use. Image analysis, combined with appropriate data processing and energy-dispersive spectroscopy (EDS) analysis, permits their characterization. Corresponding information is collected in a database. The investigations are made using an image analyzer equipped with specific software and connected to light optical and scanning electron microscopes. Data processing is performed on an auxiliary computer. The database records process and cleanliness parameters, statistical results, macrographic observations, and EDS analysis. From these, a lot of correlations can be obtained. For example, fatigue life is influenced by the largest inclusions that are not detected with classic methods. Use of distribution laws permits prediction of their probability of existence. The physical properties of inclusions can be deduced from EDS analysis and linked with shape factor and elaboration process for machinability or polishability studies.