Alumina Inclusion Behavior during Steel Deoxidation
نویسندگان
چکیده
A computational model based on classic homogenous nucleation theory, thermodynamic analysis and numerical simulation, has been developed to study steel deoxidation by aluminum in a low carbon aluminum-killed steel ladle, which calculates the nucleation and time evolution of the alumina inclusion size distribution due to Ostwald ripening, Brownian collision and turbulent collision. Starting with rapid supersaturation with Al2O3 “pseudo-molecules”, homogeneous nucleation is very fast, occurring mainly between 1μs and 10μs. The stable inclusion nuclei are predicted to be only about 10-20 Å in diameter. The growth of inclusions smaller than 1μm in radii, is mainly controlled by diffusion of pseudo-molecules and Brownian collision, and inclusions in this range tend to be spherical. The growth of inclusions larger than 2μm in radii is mainly controlled by turbulent collisions, and inclusions in this range tend to form clusters which retain minimum feature sizes of 1~2μm. Inclusion size distribution can reach 0.1~1μm at 6s and 0.1~36μm at 100s. Stirring powder has significant effect on the inclusion size distribution, it is recommended that first stir vigorously to encourage the collision of small inclusions into large ones, followed by a “final stir” that slowly recirculates the steel to facilitate their removal into the slag while minimizing the generation of more large inclusions via collisions.
منابع مشابه
Inclusion Nucleation, Growth, and Mixing during Steel Deoxidation
A computational model based on classic homogenous nucleation theory, thermodynamic analysis and numerical simulation, has been developed to study steel deoxidation by aluminum in a low carbon aluminum-killed steel ladle. The model calculates the nucleation and time evolution of the alumina inclusion size distribution due to Ostwald ripening, Brownian collision and turbulent collision. Starting ...
متن کاملInclusion Evolution during Modification of Alumina Inclusions by Calcium in Liquid Steel and Deformation during Hot Rolling Process
The production of clean steel involves the controlling, elimination, or modification of nonmetallic inclusions. In Al-killed steels, alumina is the main type of inclusion. Calcium treatment, by wire feeding, is commonly used to modify solid alumina inclusions to calcium aluminates, which exists in a fully or partially liquid phase. Liquid inclusions can improve steel castability, but make inclu...
متن کاملEvaluation of Deoxidation Process in Medical Grade of 316L Stainless Steel
In the present work, deoxidation and refining of 316LVM steel (Low carbon Vacuum Melted) during the vacuum induction melting process was studied. This grade of stainless steel is one of the most import...
متن کاملComparison of Creep Behavior in Alumina Based Ceramics Densified by Spark Plasma Sintering and Hot Pressing
Spark plasma sintering (SPS) method, as plasma activated sintering, is a method applicable for rapid sintering of metals and ceramics. Owing to the advantage of rapid heating, the alumina ceramics obtained by SPS have a grain size and density comparable to those of hot pressed ones. The increase of densification rate may be related to some difference in ion transport characteristics. This study...
متن کامل