CSP流程薄规格高强钢夹杂物控制研究

Study on inclusion controlling of thin gauge high strength steel by CSP process

为提高CSP产线薄规格高强钢钢水洁净度、降低成本,通过工业试验考察了不同钙线加入量对高强钢WJX 600钢水洁净度及夹杂物形貌、尺寸、组成变化的影响。试验结果表明,在现有的工艺条件下,钙线加入量对T.O含量影响不大,中包钢水w(T.O)可稳定控制在0.002 5%以内,w(N)≤0.004%;钙线加入量越多,钙处理后大尺寸(大于等于10μm)夹杂比例越高。通过分析,提出了轻钙处理原则和钙处理对夹杂变性目标,通过轻钙处理技术的应用以及精炼工艺优化,薄规格高强钢夹杂改判率由1.2%降至0.48%。

In order to improve the cleanliness and reduce the cost of thin gauge high strength steel in CSP process, the change of the cleanliness of molten steel and the morphology, the size and the compositions of inclusions in WJX600 steel during refining were studied by industrial experiments. The industrial results showed that, the amount of calcium wire feeding had little influence on T.O of molten steel, the T.O mass fraction of molten steel in tundish was less than 0.002 5 %, and nitrogen mass fraction was less than 0.004 %. The ratio of the inclusions with the size more than 10 μm increased with the amount of calcium wire feeding. The principles and the aim for inclusion modification by calcium were given by analysis. The judgement-changing rate of thin gauge high strength steel decreased to 0.48 % from 1.2 % by light calcium treatment and optimization of refining process.