Flux Development for Dephosphorization of Steel in Induction Furnace

Abstract

The secondary steel sectors contribute more than 55 % to total steel production in India. Steel making through induction furnace route is approximately 30 % of the total steel production in India and 70 % of steel is produced by arc furnace route and Integrated steel plants. The average phosphorus content in the steel, produced through induction furnace route using DRI, is reported to be in the range of 0.06 to 0.1 %. According to BIS standard, the phosphorus content in any structural steel is varies between 0.03%.to 0.06% depending on the application of steel. However, Induction Furnace route has its own limitations for the refining of liquid metal and treatment with flux to produce low phosphorus and low sulphur steel. The presence of high phosphorus in engineering steel component causes cold shortness, i.e. the phosphorus increase the brittle ductile transition temperature. Therefore, CSIR- National Metallurgical Laboratory has developed the flux for dephosphorization of steel in induction furnace (5-40 kg scale). It has found that phosphorus content in steel is reduced to 0.01 wt % with addition of developed flux of 2-3 wt % of the liquid steel. Hence, developed flux is suitable for phosphorus removal in induction furnace.