材料期刊网

针对硅脱氧条件下304不锈钢中出现的Al2O3夹杂物和热轧板表面存在分层缺陷的问题，通过对铸坯的大样电解、热轧板取样、扫描电镜检测分析以及FactSage软件计算等方法，主要研究了FeSi合金中残余铝质量分数对Al2O3夹杂物生成的影响，并分析了Al2O3夹杂物对不锈钢连铸和热轧板表面分层缺陷的影响。研究表明，硅脱氧条件下生产的304不锈钢整个冶炼过程中，产生Al2O3夹杂物的主要环节为GOR还原初期含有较高铝质量分数的Fe-Si合金的脱氧过程。通过FactSage软件计算得到了避免Al2O3生成时FeSi合金中所允许的最大铝质量分数。根据计算结果和现场试验得出以下结论：FeSi合金中的铝质量分数超过1.8%时，钢液中会产生Al2O3夹杂物，Al2O3进入具有较高碱度的结晶器保护渣熔渣层造成局部保护渣黏度和熔化温度快速增加形成块状的夹杂物，这些夹杂物被卷入钢液内部或者被新生铸坯表面捕捉，从而造成热轧过程中轧板的表面分层缺陷形成。当FeSi合金中的铝质量分数小于1.5%时，钢液中难以产生Al2O3类夹杂物，有效抑制了这类表面缺陷的产生。

In response to the problem about Al2O3 inclusion and surface delamination defects in the 304 stainless steel hot-rolled sheet under the conditions of Si deoxidization process,the influence of Al content in FeSi alloy on the forma-tion of Al2O3 and its effect on the continuous casting mold fluxes and the surface delamination defects of hot-rolled sheet were studied by electrolysis for slab,sampling of hot-rolled sheet,analysis of scanning electron microscopy (SEM) and calculation of FactSage software. The results showed that the main step to form Al2O3 inclusions was the deoxidization process with FeSi alloy at the beginning of the GOR reduction in the whole process of smelting. The maximum value of Al content in FeSi alloy was obtained by the calculation of FactSage software for suppressing the formation of Al2O3. Conclusions were obtained through the calculation and industrial tests that the generation of Al2O3 could be occurred as the Al content in FeSi alloy was more than 1.8%,which led to the formation of massive inclusions with high melting point and high viscosity that was the mixture of Al2O3 and mould fluxes when the Al2O3 floated into mould fluxes. Subse-quently,these massive inclusions could result the surface delamination defects in the process of hot rolled if they were entrapped by the initial solidified shell. However,Al2O3 was difficult to form when the Al content in FeSi alloy was low-er than 1.5%,so such surface delamination defects were effectively suppressed in the hot-rolled sheet.