Morphology of Nonmetallic-inclusion Clusters Observed in Molten Metal by X-ray Micro-Computed Tomography (CT)

Abstract

The removal of non-metallic inclusions in the metallurgical process greatly affects the properties of the final products. The structure of inclusion clusters plays a key role in inclusion behaviors of their removal process, such as coagulation, flotation and bubble adhesion. However, it is rare to find reports quantitatively investigating the morphology of inclusion clusters in metal system. On the other hand, to quantitatively estimate the inclusion clusters in metal, it is required to distinguish clusters on twodimensional (2D) cross-sectional images of the as-polished samples. In this study, TiB2 particle clusters were prepared in a mechanically agitated crucible containing molten Al at 1 073 K. The samples of Al-TiB2 were measured by X-ray micro-computed tomography (micro-CT) to obtain the three-dimensional (3D) information of TiB2 particles and clusters in solid Al. The images of 3D particle clusters in solid Al were extracted and reconstructed by self-developed programs. A series of parameters were defined to describe the 3D characteristics of clusters and their 2D cross-sections. The effects of agitation time and speed on the cluster structure were investigated. A program was developed to distinguish clusters in 2D crosssections through the use of the 3D cluster information (DC-2D-3D) obtained from X-ray micro-CT.KEY WORDS: inclusion coagulation; three-dimensional analysis; morphology of cluster; two-dimensional cluster; X-ray micro-CT.

Three-dimensional Observation of Nonmetallic Inclusion Clusters in Solid Metal by X-ray Micro-CT

“…The samples of aluminium with particle clusters were prepared in the mechanical agitating crucible, 5,17,18) which contains molten Al and particles (TiB 2 or SiC). The molten aluminium with particles was stirred in a crucible at 973 K to prepare the particle clusters in aluminium.…”

“…16) The current authors' group has applied the X-ray micro-CT to study the 3D structure of TiB 2 and SiC particle clusters in aluminium. 17,18) The coagulation of SiC particles in molten aluminum was studied based on the 3D observation of the particle clusters, 5) which attracted quite a lot interests from researchers. In this study, we disclose the details of the development of the 3D observation method for Al-TiB 2 and Al-SiC systems.…”

Comparison of Agglomeration Behavior of Fine Particles in Liquid among Various Mixing Operations

“…It is important to remove nonmetallic inclusions from molten steel by agglomeration, coalescence and flotation [1][2][3][4][5] for the purpose of obtaining clean steel. Many experimental and theoretical studies have been done on the agglomeration behavior of fine particles in liquid: agglomeration structure by using a fractal dimension, [6][7][8][9][10][11] wettability of particles, 12,13) heterogeneous agglomeration with a different surface electrification and size, [14][15][16][17][18] particle collision frequency in turbulent flow, 19,20) particle-size grouping.…”

Reliability of Inclusion Statistics in Steel by Stereological Methods

“…The modified SS method is then applied to translate the 3D PSD into the 2D PSD, which showed a good agreement. 18) Though the reliability of the stereological methods is critical, it is not easy to be clarified due to the experimental errors. Takahashi and Suito [20][21][22] developed a simulation model that contained randomly dispersed spherical particles to estimate the accuracy of SS method.…”