Evaluation of size distribution of small inclusions dispersed in molten steel by small angle diffraction high brilliant X ray

钛氧化物具有多种不同的晶体结构，其结构随钛在Fe-Ti-O系统中的含量不同而不同。此外，它们还与氧化铁形成化合物和固溶体。因此，了解具有不同晶体结构(不同晶格距离)的钛氧化物的析出行为对发展氧化物冶金技术非常重要。因此，作为第一步，对各种钛氧化物的还原平衡进行了热力学评估。(1)用电子背散射光谱对Fe-Ti-O合金熔体中生成的约1μm的氧化钛进行了物相鉴定。在此基础上，准确地确定了Fe-Ti-O系熔体与不同的钛氧化物熔体平衡时的氧浓度范围。(2)对于Fe-Ti-O系熔体，用DTA测量了形核起始温度，对Fe-Ti-O合金熔体中氧化钛的形核形成温度进行了测量，发现形核起始温度随熔体中钛含量的不同而不同。此外，为了建立二维沉淀行为与实际三维行为之间的关联，在显微镜下观察了溶液中CaCO3的沉淀行为。基于分形模型，对降水行为在二维和三维空间的相关性进行了评价。在进行这些实验的同时，发现用同步辐射对钢水中的析出粒子进行小角度分析是相当困难的。因此，用常规X射线小角衍射法分析了CaCO3在溶液中的成核行为，证实了直径在10μm左右的CaCO3颗粒的分布评价是可行的。

Ti oxides have a lot of different crystal structures, and their structures varies depend on Ti concentration in the Fe-Ti-O system. Furthermore, they form compounds and the solid solutions with the Fe oxide. Therefore, understanding of the precipitation behavior Ti oxides that have a various crystal structure (various lattice distance) can be very important to develop the oxide metallurgy technology. Thus, as first step, and thermodynamic evaluation of the deoxidation equilibrium of various Ti oxides have been carried out. (1) The phase identification of Ti oxide of about 1μm generated in melt Fe-Ti-O alloy was carried out by using EBSD. Based on the results, the range of the oxygen concentration of molten Fe-Ti-O system in equilibrated with various Ti oxides melt Fe-Ti-O alloy was accurately determined. (2) For molten Fe-Ti-O system, the nucleation starting temperature was measured by using DTA, measurement of the nucleation generation temperature of the Ti oxide from melt Fe-Ti-O alloy was carried out, and it has been found that the nucleation gstarting temperature vary based on Ti concentration in molten Fe-Ti-O system. Moreover, to establish the correlation between the 2-dimensional precipitation behavior and actual 3-dimensional behavior, CaCO_3 precipitation behavior from the solutions was observed by using the microscope. The correlation of precipitation behavior in two dimensions and three dimensions was evaluated based on the Fractal model. Along with carrying those experiments, it was found that the small angle analysis of precipitated particles in the molten steel by synchrotron radiation is rather difficult. Therefore, the nucleation behavior of CaCO_3 from the solution was analyzed by using conventional X-ray with small angle diffraction analysis, and was confirmed that the distribution evaluation was possible for the particles with up to the diameter of about 10μm.