Abstract
Recent inclusion models are mainly focused on the compositional evolution of inclusion, steel and slag. Due to the importance of inclusion size distribution to steel properties, the evolution of inclusion size distributions should also be accounted for. As the first step to establish a model to predict the evolution of inclusion size distribution, the nucleation, growth and removal of alumina inclusions in molten steel were modeled by combining Kampmann and Wagner numerical model for nucleation, growth and coarsening with particle size grouping method. The model could simulate the time evolution of the size distribution of alumina inclusions after aluminum de-oxidation. The model was validated by using the experimental size distribution data of alumina inclusions available in the literature. The model calculation results were also compared with previous simulation results. The influences of interfacial tension between steel and inclusion and diffusion coefficient on the calculated inclusion size distribution were investigated. As interfacial tension between steel and alumina increases, the maximum number density decreases and the peak value of radius increases. As diffusion coefficient increases, the maximum number density decreases and the peak-value radius increases. The calculated size distribution curves showed a change from log normal to fractal, which is due to the change of dominating mechanisms for crystal growth and agglomeration.
Highlights
DEOXIDATION of steel during secondary metallurgy generates enormous non-metallic inclusions which are detrimental to mechanic properties of steels.[1]
Comparison with experimental work by Nakajima et al The present model was applied to calculate the size distribution of alumina in Al deoxidation experiments performed by Nakajima et al.[30] and the calculation results were compared with the experimental three-dimensional size distribution of alumina inclusions after Al de-oxidation
Fe–10mass pct Al deoxidizer was added into the 70 g Fe–10 mass pct Ni melts with initial oxygen content between 100 and 120 ppm, the melt was stirred for 10 s with an alumina rod
Summary
DEOXIDATION of steel during secondary metallurgy generates enormous non-metallic inclusions which are detrimental to mechanic properties of steels.[1]. Zhang and Pluschkell[4] proposed a numerical model to simulate the nucleation, Ostwald ripening and agglomeration due to Brownian and turbulent collisions of inclusions. An improved model was later put forward by Zhang and Lee.[6] They divided the total size spectrum into discrete regime and sectional regime to solve the population balance model (PBM) efficiently. Later, this model was combined with a Computational Fluid Dynamics (CFD) model to predict the size distribution of alumina at any position in ladle.[7] Lei et al.[8] developed a similar numerical model to simulate the nucleation and growth of inclusions. It is shown that the KWN model can be intimately compatible with the PSG method, and there is no need to separate the total size spectrum into the discrete regime and the sectional regime
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