基于同步辐射的钢中夹杂物三维形态表征及其去除机制研究

To remove and control the inclusions is one of the hot topics of high quality steel producing. It is significant to obtain and analyze the morphology of the inclusions in steel, which plays a key role in studying the metallurgy behaviors and reducing the harm of inclusions. The morphology of many inclusions in steel have been recognized as irregular and complicate cluster shapes. The most popular metallographic method can only observe a part of a cluster on the cross sections. The applicant obtained the three dimensional morphology of the TiB2 and SiC clusters in aluminium by using the large synchrotron radiation facility. The spatial resolution of the 3D clusters was 0.5µm. In this study, we propose to obtain the high resolution 3D morphology of inclusions in steel by using the synchrotron radiation facility. By introducing self-defined parameters, the morphology of inclusions is described quantitatively. A software would be developed to extract 3D inclusions in steel, which are analyzed to obtain their statistical characterizing parameters. The 3D print technology is applied to copy the 3D morphology of inclusion clusters by using materials with various physical properties, such as density and wettability. The removal of inclusion clusters, such as floating, bubble adhesion, and separation at slag-steel interface, are studied by cold model experiments. The impact of the size, density, wettability, and 3D morphology of inclusions, bubble size and interfacial tension of slag and steel on their removal behaviors would be clarified. The research work would be of practical significant for the fundamental studies on the inclusion removal in steel.

减少和控制钢中夹杂物是生产高品质钢的热点问题，正确而全面的获取和分析钢中夹杂物的形态是研究夹杂物冶金行为并减少其危害的关键。钢中夹杂物多呈不规则和复杂的团簇结构，而目前普遍采用的金相法只能观察其二维截面的局部特征。申请人前期利用日本大型同步辐射光源成功获取了铝中TiB2和SiC团簇的三维形态，空间分辨率达0.5µm。本项目提出利用同步辐射光源观察钢中各类夹杂物的三维形态，并自定义参数定量表征其形态特征；拟开发软件提取钢中夹杂物三维形态，归纳具有统计学意义的钢中各类夹杂物三维形态特征参数；拟采用具有不同密度和润湿性的材料，通过3D打印还原夹杂物三维结构，设计冷态模型实验，系统研究夹杂物在钢液中上浮、气泡捕捉及渣钢界面分离等去除行为，阐明夹杂物尺寸、密度、润湿性、三维形态以及气泡尺寸和渣钢界面张力对夹杂物去除行为的影响规律。本项目的研究工作将对钢中夹杂物冶金行为的基础研究有重要的现实指导意义。

本项目针对钢中夹杂物表征和去除行为研究模型中的缺陷问题，通过上海大型同步辐射光源BL13W1线站和BL16U2的高分辨X射线显微CT，建立了钢中夹杂物的三维表征方法，确定了X射线显微CT观察钢中夹杂物的实验参数条件，获得了TixOy、MnS、TiN、Al2O3等典型钢中夹杂物的三维形态。根据夹杂物的形态特征，定义了一系列的三维形态特征参数，定量表征夹杂物的三维形态。基于ImageJ开源软件平台，优化了夹杂物三维形态提取程序，结合X射线相位恢复算法，自主开发程序成功消除了X射线显微CT图像中的伪影，大大提升了CT图像的质量，获得了具有统计学意义的钢中夹杂物三维形态特征参数，构建钢中夹杂物形态定量分析方法，为钢中夹杂物运动行为的数学模型研究提供基础数据。针对钢中Al2O3夹杂物团簇的复杂结构，对其三维形态进行了体视学分析，建立了Al2O3夹杂物团簇分形维数与其尺寸的定量关系。通过高分辨3D打印技术制取了夹杂物团簇，模拟钢中Al2O3夹杂物团簇，进而通过水模型实验和数值模拟研究方法，研究了夹杂物团簇在钢中的上浮及其在渣钢界面的分离去除过程，系统研究了夹杂物尺寸和形态以及流体的物理化学特性对夹杂物去除行为的影响规律，确定了钢中夹物上浮终端速率，获得了夹杂物团簇尺寸和形态对其在渣钢界面分离去除行为的影响规律，为钢中夹杂物去除行为研究工作建立新的方法和依据。