Production of low phosphorus steels from high phosphorus Indian hot metal: Experience at Tata Steel

Abstract

The position in India on the phosphorus front vis-a-vis iron and steel operations elsewhere in the world is, and will remain, most unfavourable since Indian iron ores contain high phosphorus and coal (and therefore, also the coke), has high ash and phosphorus in the Indian subcontinent. While dephosphorization of hot metal is theoretically ruled out in the Indian context, dephosphorization of liquid steel can also not be considered because of its adverse effect on ladle refractories and steel cleanliness.

For a large proportion of the steels made through the LD-slab caster-hot strip mill route at Tata Steel, the phosphorus content required in the product is 0·020% max and in some grades, it is restricted to 0·015% max. Various control strategies evolved to make low phosphorus steel at Tata Steel are discussed in the paper. The major steps which have significantly reduced the phosphorus levels are described.