Information in the ladle-metallurgy files encompasses the following subjects: review of ladle-refining technologies, ladle-refining furnaces, ladle stopper-rod assembly, ladle temperature loss, vacuum degassing, RH process for circulating-flow degassing, and the SPAL ladle furnace and low-nitrogen steel production.
Analysis: Ladle Metallurgy is synonymous with a number of other terms in the steel-production lexicon, including ladle refining, ladle treatment, and secondary refining, all referring to a wide variety of steel-processing techniques from ladle and stream vacuum degassing, to wire and particle injection, to gas and induction stirring. Some ladle metallurgy systems employ heaters in what are known as ladle furnaces, which make it possible to separate the melting and refining phases of steel production and thereby more effectively coordinate primary melting in the BOF or electric furnaces, which are batch processes, and the continuous casting of semifinished shapes.
To facilitate the production of “clean” steel, ladle metallurgy desulfurizes, deoxidizes, removes inclusions, closely controls chemistry and temperature, and, with vacuum degassing, removes hydrogen and produces low-carbon steels. By providing batch-to-continuous coordination, ladle metallurgy has become indispensable in attaining the design throughputs of high-production continuous casters by helping to assure a steady supply of clean, consistently heated steel.
Ladle metallurgy boosts productivity in the BOF and electric furnaces by limiting their role primarily to melting, which augments the supply of refined steel for casting and extends the life of furnace linings. It also gives BOF operators added flexibility in selecting charge materials by permitting a greater proportion of scrap to be used, thereby alleviating the impact of coke or hot-metal shortages. Finally, ladle metallurgy makes more efficient use of expensive alloys, given the high rates of recovery and close chemical analyses it affords.