300 t RH炉化学升温工艺对IF钢洁净度的影响

为了研究RH炉化学升温工艺对IF钢洁净度的影响， 针对RH不同阶段进行化学升温，通过取样分析对铸坯全氧、夹杂物数量密度分布、夹杂物尺寸三指标进行系统分析，定量评价RH化学升温节点及升温幅度对钢水洁净度的影响。结果表明，RH化学升温时，钢水洁净度恶化，铸坯全氧质量分数增加了0.000 8%～0.001 3%；在同一升温值、不同升温节点条件下，以RH升温32～36 ℃为例，方案4团簇状夹杂物尺寸达到20 μm，小于方案5团簇状夹杂物尺寸30 μm。因此，采用“脱碳中前期＋脱碳终点”升温工艺，夹杂物尺寸优于“脱碳终点”升温工艺。生产实践中，若钢水进RH炉温度低，在RH升温操作不可避免的条件下，应采用“脱碳中前期＋脱碳终点”升温工艺，以减少RH升温操作对钢水洁净度的影响。

Effect of chemical heating process of 300 t RH furnace on IF steel cleanliness

In order to study the influence of RH furnace chemical heating process on the cleanliness of IF steel. For the different stages of RH for chemical heating up, a systematic analysis of the three indexes, including the total oxygen of slab, number density distribution of inclusions and inclusions size was made to have a quantitative evaluation of the impact of RH chemical heating node and temperature on steel cleanliness. The results showed that when the RH was chemical heating up, the cleanliness of the steel was worse, and the total oxygen of the billet was increased by 0.000 8%- 0.001 3%. Under the condition of different heating points at the same temperature, in the case of RH temperature of 32- 36 ℃, the cluster inclusion size of 20 μm for scheme 4, was less than that of 30 μm for scheme 5. Therefore, adopting the heating process of "pre- decarbonization and terminal decarbonization", the inclusion size was less than that of "terminal decarburizing" heating process. In the production practice, if the molten steel entered the RH with low temperature, and the RH heating operation was unavoidable, the "pre- decarbonization and terminal decarbonization" heating process should be adopted to reduce the influence of RH heating operation on the cleanliness of molten steel.