Model Analysis on the Behavior of Niobium in High Carbon Steel

A coupling thermodynamic model quantificationally described elements segregation and inclusions precipitation during solidification process of high carbon steel was proposed.According to the SEM and EDX,the model could completely consist with experiment results.Effects of mass fraction of niobium on the state of niobium and niobium carbide during the solidification process of high carbon steel were stu-died.The results as follows:(1)Niobium carbide and solid niobium solution are gradually precipitated during solidification process.With increasing mass fraction of carbon,concentration distribution of solid niobium solution is decreased at first and then increased.(2)With in-creasing mass fraction of niobium,both the temperature and content of niobium carbide precipitation are increased;the average precipitation content of solid niobium solution is gradually increased.The increment of niobium carbide is more remarkable.