Abstract
The purpose of the present experiment was to give a new method for the production of low phosphorus ferrochrome base alloys to be added for making stainless steels with an extremely low phosphorus level. Ferrochrome base alloys containing Ni (10, 20, 25, and 30%) and C (0.03, 1, 1.5, 3, and 6%) were remelted in an ESR furnace of a small scale under an inert atmosphere. Ca-CaF2 flux was used as an electro-flux. The experimental results are summarized as follows.
(1) Chemical analyses of remelted alloys showed that S, O, and P were simultaneously removed.
(2) Carbon was found to be transferred from carbon-ferrochrome to the flux according to the reaction (Ca) +2C= (CaC2).
(3) The remelting condition of alloys was determined by the melting point, Ca content of the flux, and the electric power.
(4) The 1-3%C and 25-30%Ni alloys were smoothly remelted. The degree of phosphorus removal was high (>about 75%). The observed values of the distribution ratio of phosphorus between the molten flux and the liquid alloys were found to be close to those predicted from the relation obtained in our earlier work, Lp=4 (%Ca) (%Ca) 2.
As for the ferrochrome and stainless steel making processes, the present dephosphorizing method can be applied to the commercial production of low phosphorus ferrochrome with about 3%C or 25-30%Ni.
