Fe-Si合金热轧氧化铁皮结构演变及氧化界面控制机理的研究

随着钢铁生产技术的发展，高附加值的硅钢（Fe-Si合金）已成为各大钢铁企业的研发重点。热轧过程中，较高含量的溶质元素Si对O的亲合力大于Fe, 容易发生内氧化，造成外层氧化铁皮结构混杂、内氧化界面凸凹不平，严重影响产品表面质量，加重酸洗难度，并降低磁性能。本项目针对Fe-Si合金热轧流程生产特点，围绕其氧化铁皮结构、内氧化物、氧化界面控制问题开展系统研究，弄清加热、热轧、冷却、卷取各阶段的高温氧化行为，揭示内氧化物及氧化界面的形成与演变机理。并从热力学和动力学理论出发研究其对后续连续冷却条件下氧化铁皮共析转变的遗传影响，获取相应的连续冷却条件下的共析转变曲线。据此建立热轧流程条件下Fe-Si合金氧化铁皮结构及内氧化界面控制的关键理论要点，开展加热、热轧、连续冷却的工艺优化设计，找到有效改善Fe-Si合金热轧板表面质量的关键工艺窗口。

With the technical improvement of steel process, high value-added silicon steel (Fe-Si alloy) has become the focus of the research and development of the major steel companies. During hot rolling process, due to the greater affinity of the main solute element silicon for oxygen comparing to Fe, the deterioration of the oxide scale structure and the unevenness of the oxide interface has seriously affected the surface quality of products and reduced the magnetic properties. According to characteristics of the hot rolling process of Fe-Si alloy, this research will focus on the structural changes of oxide scale, inner oxide precipitation and the evolution control of the oxide interface. The high temperature oxidation behavior in different segments of the process is revealed, such as reheating process, hot rolling process, cooling process and coiling process. The mechanism of transformation and evolution of inner oxide precipitation and oxide interface is also studied. And from the aspect of thermodynamic and kinetic theory, the genetic impact of the eutectoid transformation of the oxide scale on the subsequent continuous cooling process is concerned. The eutectoid reaction curve is obtained from experiments. The key theoretical points about oxide scale structure evolution and control mechanism of oxidation interface of Fe-Si alloy during hot rolling are established. The optimized processing design including heating, hot-rolling, continuous cooling process is carried out to find the optimal process window to improve the surface quality of Fe-Si alloy.