宽大断面连铸坯凝固末端变形过程溶质偏析行为及压下工艺研究

项目名称： 宽大断面连铸坯凝固末端变形过程溶质偏析行为及压下工艺研究

项目编号： No.51474058

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 祭程

作者单位： 东北大学

项目金额： 80万元

中文摘要： 严重的宏观偏析已成为生产高致密度、均质化宽大断面连铸坯的最大障碍。准确揭示宽大断面连铸坯凝固末端变形、溶质偏析、裂纹产生与扩展规律，开发凝固末端压下工艺，是解决此问题的关键。鉴于此，本研究拟开发溶质微观偏析理论计算模型和预测模型，实现液相溶质浓度和冷速连续变化过程中溶质微观偏析与相变的准确而快速预测；研究开发宽大断面连铸坯两相区变形与溶质偏析相耦合的计算模型，准确描述压下过程中凝固、变形、溶质宏观传输、溶质微观偏析等宏微观现象及其相互作用规律，从而揭示宏观偏析的形成与控制机理；准确描述凝固前沿ZDT-ZST区间综合应力应变，研究并提出宽大断面连铸坯凝固末端压下过程内裂纹形成与扩展判据，及压下限定准则；在上述研究基础上，针对压下变形量大、非均匀凝固、高内裂风险的具体特点，研究提出适用于宽大断面连铸坯的凝固末端压下参数理论计算模型与工艺装备技术，并通过工业应用研究，验证工艺的合理性与可靠性。

中文关键词： 连铸；宽大断面；坯壳变形；溶质偏析；凝固末端压下

英文摘要： The macro-segregation of carbon and alloying elements during the continuous casting process afflict the manufacture of homogeneous wide-large section slab or bloom. In order to conquer this problem, the solidification end reduction technology should be established according to the accurate description of the shell deformation, the solute segregation and the formation and propagation of the internal cracks in wide-large section slab casting process. In this study, the theory calculation model and predication model for solute micro-segregation will be established, and the phase transfer and the solute micro-segregation could be predicted quickly and accurately, when the cooling rate and the solute concentration is unsteady. The coupled model of mushy zone deformation and solute segregation will be presented. The transport phenomena and their interaction during wide-large section continuous casting process, such as solidification, deformation, solute diffusion and segregation, could be described exactly, and then the formation and control mechanism of the mushy zone macro-segregation could be derived. The occurring and propagation criterion of internal cracks for wide-large section continuous casting process could be established based on the accurate prediction results of the comprehensive stress-strain distribution between the ZDT and ZST area, while the limitation criterion of solidification end reduction could be derived also. After that, according to the characteristics of solidification end of wide-large section slab and bloom, such as the large reduction amount, the uneven shell growth, and the high rates of the internal cracks, the theory calculation model and technological equipment will be developed for reducing macro-segregation, and the industrial application will be carried on in order to verifying its reasonability and reliability.

英文关键词： continous casting;wide-large section;shell deformation;solute segregation;solidification end reduction