次世代革新的鉄鋼材料開発のためのスピネル系介在物の生成・変質メカニズムの解明

本文的目的是阐明MgO-Al_2 O_3（MA）尖晶石和CaO-Al_2 O_3型夹杂物形成的Mg和Ca的来源。针对镁铝尖晶石型夹杂物的形成，研究了镁基耐火材料和含镁渣中镁的溶解行为。这里，关于MgO基耐火材料，使用MgO-Cr2 O3耐火材料和MgO-C耐火材料两者。针对CaO-Al_2 O_3型夹杂物的形成，研究了含CaO渣中Ca的溶解行为。不同成分的炉渣中的MgO和CaO都被钢中的Al还原，Mg和Ca被溶解到钢中。在仅用MgO饱和渣的实验中，当Al含量为0.25%时，形成富MgO夹杂物，而当Al含量为2.5%时，尖晶石夹杂物中MgO含量增加到饱和状态。在实际LF处理过程中，Al_2O_3夹杂物转变为MgO-Al_2 O_3尖晶石夹杂物和少量CaO-Al_2 O_3夹杂物。因此，在工业操作条件下，通过渣-钢反应，不会形成CaO-Al 2 O3夹杂物。在此基础上，我们发现，在炼钢精炼过程中，CaO-Al_2 O_3夹杂物的形成主要是由合金中的Ca，特别是Fe-Si引起的，而夹杂物的形成主要是由Al_2 O_3向MgO-Al_2 O_3尖晶石的转变。为了阻止CaOAl 2 O3夹杂物的形成，应严格控制合金中的杂质。

The purpose of present study is to clarify the source of Mg and Ca for the formation of MgOAl2O3 (MA) spinel and CaO-Al2O3 type inclusions. For the formation of MA spinel type inclusion, the dissolution behavior of Mg from both MgO-based refractory and MgO-containing slag were studied. Here, about the MgO-based refractory, both the MgO-Cr2O3 refractory and MgO-C refractory were used. For the formation of CaO-Al2O3 type inclusion, the dissolution behavior of Ca from CaO-containing slag was studied. Both MgO and CaO in slag of different compositions were reduced by Al in steel, and Mg and Ca were dissolved into the steel. In the experiments using slag only saturated with MgO, when the Al content was 0.25%, the MgO-rich inclusion formed, while when the Al content was 2.5%, the MgO content of spinel inclusions increased to saturation.In order to confirm the above conclusions, an industrial experiment was conducted. During the actual LF treatment, the Al2O3 inclusion transformed to MgOAl2O3 spinel inclusion and few CaO-Al2O3 inclusion. Therefore, By the slag-steel reaction, CaO-Al2O3 inclusion could not form under the condition of industrial operation. Then, we found that the Ca for the formation of CaO-Al2O3 inclusion was from the added alloy, especially Fe-Si.Based on these results, we found that during the refining process of steelmaking, the inclusion only transformed through the routine of Al2O3 to MgOAl2O3 spinel. In order to hinder the formation of CaOAl2O3 inclusion, the impurity in the added alloy should be strictly controlled.