Characterization and analysis of alumina clusters in steel by X-ray Micro-CT

Abstract

The properties of steel are affected by the non-metallic inclusions. It is critical to control the morphology of inclusions for producing the high-quality steel. However, due to the morphology of inclusions is complex and diverse, it is difficult to reveal the real morphology of inclusions by using the traditional two-dimensional (2D) observation method, and making it hard to quantitatively analyze the size and morphology of inclusions. In this study, the three-dimensional (3D) morphology of the alumina clusters in steel samples was observed by using the X-ray Micro-CT in the beamline of BL16U2 at Shanghai Synchrotron Radiation Facility (SSRF). Avizo software was used to reconstruct the 3D morphology of the alumina clusters, which intuitively shows the actual morphology of alumina clusters. The accuracy of 2D and 3D observation methods is discussed based on the stereological analysis of individual alumina cluster. A series of parameters were defined to characterize the morphological characteristics of the alumina clusters based the 3D observation. The fractal theory was introduced to quantitatively describe the morphological of alumina clusters. In the current study, the 2D fractal dimension of alumina clusters was determined as 1.64. The complexity of 3D morphology of alumina clusters was analyzed by 3D fractal dimension and shape factor. The current work provides an effective method for quantitative description of the morphology and spatial distribution of inclusions, which provides an important reference for effective control of alumina inclusions.