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通过对低碳含铝钢20Mn2精炼过程的取样分析,得出精炼渣的熔化温度偏高,渣中存在大量固相Ca O,并导致钢中含有Ca O类夹杂物,精炼渣吸附夹杂物能力差.利用Fact Sage热力学计算,从渣的低熔点区域控制和渣-钢反应这两个方面对渣系进行研究与优化.结果表明,Ca O/Al2O3质量比在1.5左右添加质量分数为3%Ca F2可以有效降低渣的熔化温度,渣的熔化温度随着Ca F2含量的升高呈现先降低后升高的趋势,Mg O的质量分数控制5%左右低熔点区域面积达到最大.在Si O2质量分数大于30%区域,钢中氧含量大体上随着Ca O/Al2O3质量比的增加而降低,在Si O2的质量分数低于30%区域随着Ca O含量的升高而降低,钢中酸溶铝含量在Si O2含量高的区域随着Al2O3/Si O2质量比的增加而升高,在Si O2含量低的区域随着Ca O/Si O2质量比的增加而增加.根据热力学分析结果得出合理的渣系范围:Ca O 50%~60%,Al2O320%~35%,Si O25%~10%,Mg O 5%~8%,Ca F20~5%.优化渣系的实验结果表明,优化后渣系熔化温度降低,钢中夹杂物数量、面积和平均尺寸均有明显下降.
Through the sampling analysis of 20Mn2 refining process of low-carbon aluminum-bearing steel, it is concluded that the melting temperature of refining slag is high, a large amount of solid-phase CaO exists in the slag, and CaO-containing inclusions are contained in the steel, and the ability of refining slag to adsorb inclusions Poor.Using Fact Sage thermodynamic calculation, slag system was studied and optimized from the aspects of slag low melting point control and slag-steel reaction.The results show that the mass ratio of CaO / Al2O3 is about 1.5% Ca F2 can effectively reduce the melting temperature of slag, the melting temperature of slag decreases firstly and then increases with the increase of Ca F2 content, and the area of low melting point region is about 5% The content of oxygen in steel decreases with the increase of mass fraction of CaO / Al2O3 in the mass fraction of more than 30%, and decreases with the increase of CaO content in the region where the mass fraction of Si O2 is less than 30% The content of acid-soluble aluminum increases with the mass ratio of Al2O3 / Si O2 in the region with high Si O2 content and increases with the mass ratio of CaO / Si O2 in the region with low Si O2 content.According to the results of thermodynamic analysis Obtained a reasonable slag system range: CaO 50% ~ 60%, Al2O320% ~ 35%, Si O25% ~ 10%, MgO5% ~8%, CaF20 ~ 5% .Experimental results of optimizing slag system show that the melting temperature of slag system decreases after optimization, and the number, area and average size of inclusions in steel decrease obviously.