Effect of Rare Earth Metals Injection & Gas Stirring on Cleanliness of Pipeline Steel

Abstract

A full scale plant trial was done to find the effect of rare earth metals (RE) wire injection on deoxidation, desulphurization and inclusion of steel rolling pipe. The melt was stirred by nitrogen from the bottom of the ladle. For about 5 to 15 minutes. As a result of addit- ion of RE at the rate of 0.2 kg/t substantial deoxidat- ion, desulphurization and reduction of oxygen activity from about 50 to 7 ppm level took place. Addition of 0.1 kg/t of RE resulted in difference of oxygen by 0,01278%, while the oxygen contentin the bath was 0.010%. When RE addition was done over 0.03 kg/t, oxysulphides and its complex were formed depending upon RE and aluminum contents. The stirring of the melt by gas helped in reducing quantity of inclusions.