Interaction between Ti-bearing ultra-low carbon solid steel and mold flux at 1400 degrees C

摘要

Laboratory scale experiments on the reaction between mold flux and solid titanium (Ti) bearing ultra low carbon (ULC) steel were carried out at 1400 degrees C. It was found that the composition of mold flux particles changed after the interactions, which was resulted from the reduction of flux components by the aluminum (Al) and Ti in steel, leading to the decrease of SiO2 and the increase of Al2O3 and TiOx in flux particles. A layer of oxides was precipitated in the steel near the steel-flux interface. Al2O3 particles were firstly precipitated and then transformed into Ti-Al-O type with the decrease of the distance from the interface and the increase of reheating time, accompanying with the increase of the particle size. The precipitation of particles was estimated to result from the reoxidation of the steel matrix by the oxygen diffused from the mold flux, which would further increase the detriment of the entrapped mold flux to the cleanliness and surface quality of the rolled sheets of ULC steel.