Possibility of conversion of Indian phosphoric basic pig iron to steel using basic side-blown converter

Abstract

A number of heats were made by refining pig iron having an average phosphorus content of 0.3% and silicon of 1.5% in this half-tonne basic-lined side-blown converter using a single row of tuyeres. After standardizing the blowing technique by using cold air only, the consistency in the chemical composition of steel made was established by performing consecutive blows continuously. By adopting a double slagging process about 96% of phosphorus and 60% of sulphur was eliminated from the pig iron. The consumption of flux and the deoxidizers were minimized by slag control and blowing skill to 100kg and 2kg per tonne of hot metal respectively. The average blowing time was 30 minutes at an average air pressure of 0.27 kg/cm2 for half-tonne of hot metal. The yield of the blown metal varied between 70 to 80% of the hot metal employed. The ingots were bottom cast and a few of them cut and forged to suitable sizes which, when hot rolled, were reduced to rods of 6mm diameter successfully. Improvement in the lining life was observed when dead burnt magnesite below one mm size with molasses as binder were used. (Sarvashri A.N. Kapoor, S.K. Biswas and Santokh Singh, Scientists, National Metallurgical Laboratory)