The oscillation of argon oxygen decarburization (AOD) converters is flow related and depends on the process parameters (e.g., vessel geometry, melt fill height, process gas type and blowing rate, vessel tilting angle, as well as geometry, number, and arrangement of the side-wall nozzles). For a 120-ton AOD converter with seven submerged side-wall nozzles, plant tests, physical simulations on a 1:4 scale water model, and computational fluid dynamics simulations have been done. The investigations show that the penetration depth of an inert gas jet into the melt does not exceed approximately 0.4 m. The plumes are located close to the nozzle-side converter wall and induce a large-scale primary vortex as well as intensive surface movements; both are responsible for the oscillation. Several process mechanisms were investigated. The oscillation is highest in the last stage of the dynamic blow and is still high during the reduction stage. As the amount of inert gas increases, the vibration level also increases. Inert gas has a greater influence on the oscillation than oxygen. Tilting the converter around 8 deg clearly leads to more intensive oscillations. Increasing the blowing rate increases the forces and torques acting on the vessel, whereas the oscillation frequency remains nearly constant. A varying fill level does not influence the vibration level the same way as the blowing rate. The operational test shows, for example, that the maximum torque does not depend on the heat size when the latter varies between -8 pct and +21 pct of the nominal heat size. The water model test shows decreasing forces and torques with a rising fill level.

The mixing enthalpy AH m of the liquid system Ni-Zr was measured in the Nirich range at 1916 K up to .Xzr = 0.34 at % and for the first time in the Zr-rich range at 2270 K up to -X' Ni = 0.54 at %. Using the thermodynamic-dapted power series, a composition-and temperature-dependent description of AH m was given. Furthermore, the partial differentiation of AHm(x, T) by T yielded the excess heat capacity CpX~(x, T). The existence of chemical short-range order (associate) in the vicinity of Ni7Zr2 and NiZr was shown and was discussed with reference to AHm(x, T) and CpX~(x, T) ( 1748 to 2270 K). With decreasing temperature, the influence of chemical short-range order tended toward the composition NiZr.

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The mixing enthalpies of liquid binary iron‐nickel, nickel‐chromium and iron‐chromium alloys were measured by levitation alloying calorimetry. The mixing enthalpy of iron‐nickel alloys is asymmetric and was described by an equation according to the modified quasichemical solution model. Liquid nickel‐chromium alloys were determined to conform to a regular solution model whereas the system iron‐chromium behaves ideally. Based upon the analytical descriptions obtained for the binary systems an isoenthalpy diagram for liquid ternary iron‐nickel‐chromium alloys was calculated. Mixing enthalpy measurements of the concentration section Fe35Ni65 ‐ Cr are in agreement with the model calculation. Iron rich alloys of the system tend to almost ideal behaviour whereas nickel rich alloys are characterized by negative mixing enthalpies up to ‐5 kJ/mol.

The mixing enthalpies of liquid Ti‐Zr, Fe‐Ti‐Zr and Fe‐Ni‐Zr alloys were measured by levitation alloying calorimetry. The mixing enthalpy of Ti‐Zr alloys is slightly exothermic and symmetric with an extreme value of −5.2 kj mol−1. It can be described according to the regular solution model. Experimental investigations of the mixing enthalpies of the strongly non‐ideal binary systems Fe‐Ti, Fe‐Zr and Ni‐Zr had already been subject of earlier works. Based on experimental data temperature dependent descriptions of the mixing enthalpies were calculated with a regular associate model. From the model parameters of the binary subsystems the mixing enthalpy of the respective ternary system can be predicted. Model calculations of the mixing enthalpies of liquid Fe‐Ti‐Zr and Fe‐Ni‐Zr alloys were performed along different concentration sections and compared with experimental data, respectively. A good accordance was observed. The mixing enthalpies of liquid Fe‐Ti‐Zr and Fe‐Ni‐Zr alloys are given at T = 2152 K and T = 1892 K in form of isoenthalpy diagrams, respectively. Moreover, with help of the temperature dependence of the mixing enthalpy the excess heat capacities of the alloys were calculated.