In the steel industry, the tap of the steel that is molten from casting processes (BOF, EAF, and LF) often requires additional refinement, also known as ladle metallics. The process involves the addition of the alloying metals as well as other components into the melting steel in order to obtain the desired properties of the finished product, including the modification of inclusions, de-oxidation, de-sulphurization and many more. While the inclusion of these metals and alloys can be achieved by bulk alloy feeding and powder spraying. A more exact and reliable technique is to use cored wires to will inject the alloys directly into the steel bath.
Cored wires consist of an outer steel sheath which is surrounded by the active calcium metal core. The sheath and core are tightly wrapped and sealed using a sintering procedure to guarantee the quality of the encapsulated active calcium. The core and sheath is then pulled together, coiled, and then inserted to the steel ladle using a core wire injection system. This makes it possible to have more precise control over the amount of additions made to the molten steel as well as much higher levels of recovery than traditional methods.
When a cored wire is placed into the molten steel, the sheath melts, and then dissolves within the steel molten, and releases the calcium metal from the ladle. This improves the quality of the molten steel because it slows down the oxidation of the metal in molten state, enhances the absorption of calcium by the molten steel and reduces the amount of gases that are harmful in the steel that is molten. The slag that is formed by the molten metal is also smaller and less dense.
The sheath that surrounds the wire that is cored also can have a positive effect on the temperature range of steel that is molten, decreasing the development of crystals of gypsum and reducing the melting point of the slag. The sheath around the steel core keeps the massive amounts of vapor that would naturally escape from the molten metal the slag, which results in a reduction of melting as well as an increase in the loss of heat.
The results of the numerical simulations match well with actual data, which proves that the model is reliable. Both the rate of slag production in the simulation of molten iron as well as the speed measured for the sheath around the wire that is cored are alike. This is also true in the case of the temperature that is measured at the slag's interface with the steel. The difference between simulation and experiment is less than 20%. This is due to the fact the fact that the model of sheath thickness was based more on the approximate radius of sheath and steel shell rather than the actual size. This allows for more accurate comparisons between simulations and experiments and a better calibration of the simulation models. This suggests that cored wires are the best way to improve efficiency of the molten steel and reduce raw material consumption within steel mills. The results are promising and indicate that a higher degree of precision is feasible for the next developments in the analysis of the integration of cored wires into liquid metal baths.
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