Evolution of MnS-MnTe inclusions during heating of tellurium treated sulfur-containing steel
HUANG Qiao1, REN Ying1, ZHANG Li-feng2
1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144, China
Abstract：The evolution of MnS-MnTe inclusions in tellurium treated high sulfur steel during the heating process was studied through laboratory experiments and thermodynamic calculations. The regularity and mechanism of change for MnS-MnTe inclusions were obtained. With the increase of the tellurium content and the Te/S mass ratio in the steel increased, the average diameter of MnS-MnTe inclusions increased while the average aspect ratio decreased. After heating, since MnS and MnTe in the steel matrix after heating fully grew and precipitated, the effect of modification after tellurium treatment on MnS inclusions was more obvious than that before heating. Meanwhile, compared with inclusions in samples before heating, with the increase of the Te/S mass ratio in the steel, the average diameter of inclusions was larger, the number density was lower and the area fraction was higher. With the increase of Te/S mass ratio in the steel, the proportion of dendritic Type II inclusions decreased while more spherical Type I and massive Type III precipitated in MnS-MnTe inclusions. Under the current experimental condition, after Te/S mass ratio reaching 0.33, the initial precipitation temperature of MnS was lower than the solidus temperature of the liquid steel, which was conducive to inhibit the formation of Type II MnS at the grain boundary during the eutectic reaction. When the Te/S mass ratio was higher than 1.35, numerous spherical pure MnTe inclusions precipitated in the steel matrix.
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2022, Vol. 32 
