Alloying elements liquid addition to optimize secondary metallurgy

During the last years, numerous secondary metallurgical technologies have been developed. The present study presents a new technology based on adding all the alloying elements in liquid state. In this new process, a molten bath of the appropriate composition is made with alloying elements and deoxidants (in an induction furnace). This molten alloy is introduced into the liquid steel at the beginning of secondary metallurgy. With this new process, in addition to improving the mixing between alloy elements and steel, its final objective is to improve the process of secondary metallurgy in order to: reduce the time of secondary metallurgy, reduce the temperature of the steel liquid, use cheaper alloying elements, improve steel cleaning by reducing the addition of inclusions by ferroalloys, thus improving steel quality, increasing the efficiency of ferroalloys and increasing productivity. All this would result in lower energy consumption due to the reduction of electric furnace times and temperatures.To achieve this goal, the first experiments with 100kg castings at laboratory scale have been performed, and the results are presented here below. Castings with solid and liquid addition of the alloying elements have been made and, the performance of the elements, the use of ferroalloys of different qualities and the final solidification microstructure have been analyzed for the 95Cr6 alloy, obtaining similar results in both processes. A more complex alloy (40NiCrMo4) has also been investigated to analyze the performance of other elements like Ni and Mo. The results obtained with both alloys indicate that the viability and the necessary requirements for a future adaptation to the industrial environment of this new technology are feasible. Tests on an industrial scale are necessary for a real estimation of the savings and environmental improvements that would lead to the industrialization of this new technology.