基于氧枪喷头磨损的转炉供氧制度

Oxygen supply system based on oxygen lance nozzle wear in converter

转炉氧枪喷头磨损会导致气体射流和冲击特性发生变化,影响炼钢熔池搅拌效果和反应速率,研究供氧制度变化对喷头磨损后氧枪搅拌效果的影响对转炉冶炼工艺优化具有实际指导意义。建立了120 t转炉及不同磨损角度氧枪三维全尺寸几何模型,研究了供氧制度变化对喷头出口磨损后氧枪射流速度、冲击特性和熔池速度的影响。发现增大氧气流量后,射流速度衰减变慢,射流聚合程度减弱,射流核心区长度增大,而枪位对射流速度的衰减影响较小。供氧制度变化后,不同磨损程度氧枪钢液面速度分布规律大致相同,冲击凹坑和底吹流股区域钢液流速快,液面波动最剧烈,而炉壁处存在部分钢液流动死区。供氧制度调整后,磨损后氧枪在熔池深度500 mm处的高速区面积均大于未磨损氧枪。熔池深度较深处,顶吹射流的影响逐渐变弱,底吹流股开始起主导作用,熔池中心区域转变为低速区。并在120 t转炉上完成了工业试验,结果表明,动态调整氧枪枪位后,3种不同磨损程度氧枪吹炼时终点平均磷质量分数分别为0.029 6%、0.029 3%和0.029 4%,终点平均碳氧积分别为0.002 1、0.002 2和0.002 2,但钢铁料消耗会增加。供氧制度调整后,增大了磨损后氧枪射流对熔池的冲击力,保证了磨损后氧枪对熔池的搅拌效果与未磨损氧枪基本一致,减轻了氧枪磨损对转炉冶炼效果的影响。

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 120tconverter 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 500mm 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 120tconverter 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 0.0296%,0.0293%and 0.0294%,the end of the average carbon-oxygen equilibrium were 0.0021,0.0022and 0.0022,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.