1. Behavior of deoxidation by-products and inclusions in high impurity containing steel during melting, deoxidation and solidification process

Research Results in fiscal year 2000

The chemical composition of high phosphorus containing molten steel after manganese-silicon deoxidation was estimated by the software for chemical equilibrium calculation gThermoCalch. It was predicted that dephosphorization efficiency of manganese silicate slag was very low in comparison with conventional CaO-bearing one and increased with increasing temperature differently from highly basic slags.

Research in fiscal year 2001F

The phosphate capacity, which is one of the important indices of phosphorus containing ability of slag , for the MnO-SiO2 bearing system was investigated by equilibrating MnO-SiO2-FetO slag and solid or molten iron.

The phosphate capacity was calculated by the equation expressed below and using phosphorus partition between metal and slag, and shown in figures.
Low temperature range
(for secondary inclusion)
@High temperature range
(for deoxidation by-product)

@The phosphate capacities for MnO-SiO2 slags are very low compared with conventional slags, indicating that the phosphorus will almost remains in metal when Mn-Si deoxidation is applied to the phosphorus containing steel.