Optimizing Ferrotitanium Wire Injection Parameters for Improving Titanium Recovery in Ladle Furnace Steelmaking

Abstract

Titanium or niobium alloying is done in microalloyed steels to improve the mechanical properties by grain refinement. Contrary to niobium, titanium addition gives additional advantages of 1) lower rolling load in the mill and 2) low ferroalloy cost. However, recovery of titanium, owing to its high affinity toward oxygen, is highly inconsistent and depends mainly on secondary steelmaking process parameters like dissolved oxygen content in steel, chemical composition of slag, addition method of alloy, fluid flow conditions of the bath during and after the addition of alloy and temperature of steel. Herein, process data have been analyzed and correlated to the chemical composition of steel and slag to understand the influence of various process parameters on titanium yield. Industrial plant trials have been conducted with a modified ferrotitanium (FeTi) addition practice. FeTi wire injection is done in seven heats with different wire injection speed and bottom argon purging rate. It has been found that 200 m min−1 of injection speed along with differential flow rate of argon from porous plugs with 35 and 6 Nm3 h−1, respectively, yields better recovery of titanium. The titanium recovery increases by 4% compared to the earlier practice of wire injection and argon purging.