The effect of different deoxidation processes on the inclusions characteristics in cold drawn tubing steel

Abstract

The non-metallic inclusions of cold-drawn tubing steel with different deoxidation processes were carried out in this study. The morphologies, compositions and size distribution of oxide inclusions in two heats were obtained by FE-SEM&EDS. The evolution of inclusion types in SM/AC process and SMA/C process were compared. In addition, it was summarized that the removed inclusion of SM/AC process was relatively more at LF station, while the removed inclusion of SMA/C process was mainly at VD station, which is closely related to the calcium treatment intensity at VD station. Moreover, kinetic model calculations of inclusion behaviour were carried out. Taking molten steelslag-inclusion-refractory four-phase equilibrium into account, and considering the aggregation, floatation, remove and modification of inclusion. The results can well explain the existence of inclusions in the actual production process and can guide the removal of inclusions in different deoxidation processes and to know the removal limits.