The effect of solidification on the formation and growth of inclusions in low carbon steel welds

Weld metal transformations in low carbon steels are strongly dependent on the size and size distribution of non-metallic inclusions. Since inclusions are nucleants to proeutectoid phases, the presence of these second phase particles shift the continuous cooling transformation (CCT) curves to shorter times. Thus, the modelling of the formation and growth of inclusions is desirable to predict weld metal microstructure and properties. In this study, a new model is proposed considering solute redistribution during solidification. The model predicts the weld metal inclusion size distribution, considering diffusion-controlled deoxidation as the primary growth mechanism. An interesting feature of this model is that it predicts the change in the shape of the size distribution curve with the solute composition and the local solidification time.