Dephosphorization of Fe-Cr-Si Alloys for Low Phosphorous Stainless Steel

Synopsis: In order to produce low phosphorous stainless steels with superior stress corrosion resistance, the possibility to remove phosphorus by the following two methods for ferro-silicochromium, which is an intermediate pro-duct for low carbon ferrochromium, was investigated. Firstly, the evaporation of phosphorus in vacuum was studied by using levitation technique, and secondly, the CaF2-CaC2 flux was used as a dephosphorizer in a plasma melting furnace. Both methods gave the phosphorous content less than 0.01%, which is low enough for the above mentioned purpose, It was found that the higher silicon content in the alloys signi- ficantly exxhanced the dephosphorization. These results also encourage the usage Of chromite ore and coke with higher phosphorous contents, if the dephosphorization process is only incorporated to the conventional process for low carbon ferrochromium production.