1. School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, Shaanxi, China; 2. Production Command and Control Center, Shaanxi Longmen Iron and Steel Co., Ltd., Hancheng 715405, Shaanxi, China; 3. Department of Steelmaking, China National Heavy Machinery Research Institute Co., Ltd., Xi'an 710032, Shaanxi, China
Abstract：Oxygen lance nozzle wear in converter can lead to changes in gas jet and impact characteristics, affecting the mixing effect and reaction rate in the steelmaking bath. Studying the effect of changes in the oxygen supply system on the mixing effect of the worn oxygen lance is a practical guide to the optimization of the converter smelting process. A three-dimensional full-size geometry model of a 120 t converter and an oxygen lance with different wear angles were established to investigate the effect of changes in the oxygen supply system on the oxygen lance jet velocity, impact characteristics and molten bath velocity after nozzle wear. It was found that after increasing the oxygen flow rate, the attenuation of the jet velocity became slower, the degree of jet convergence weakened, and the length of the jet core area increased, while the oxygen lance height had less influence on the jet velocity attenuation. After changing the oxygen supply system, the velocity distribution pattern of the steel surface of oxygen lance with different wear degrees was more or less the same, the impact dent and bottom blowing flow zone had fast steel flow velocity, and the most violent fluctuation of the liquid surface. However, there was part of the dead zone of steel flow at the furnace wall. After changing the oxygen supply system, the area of the high-velocity zone of the worn oxygen lance at a depth of 500 mm was larger than that of the unworn oxygen lance. At deeper depths, the influence of the top-blowing jet gradually became weaker, the bottom-blowing flow began to play a dominant role and the central area of the molten bath was transformed into a low-velocity zone. And in the 120 t converter on the completion of industrial tests, the results showed that the dynamic adjustment of the oxygen lance height, three different degrees of wear oxygen lance blowing at the end of the average phosphorus content of 0.029 6%, 0.029 3% and 0.029 4%, the end of the average carbon-oxygen equilibrium were 0.002 1, 0.002 2 and 0.002 2, but increased steel material consumption. After changing the oxygen supply system, the impact of the worn oxygen lance jet on the molten bath is increased, so that the mixing effect of the worn oxygen lance on the molten bath is basically the same as that of the unworn oxygen lance, which reduces the influence of the worn oxygen lance on the smelting effect of the converter.
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2023, Vol. 58 
