基于熔渣成分连续变化的大型电渣锭凝固机理的基础研究

ESR technique is widely used in special steel production process. In recent years, the inhomogeneity of ingot along the lengh direction has been a key issue to enhance the quality of the esr steel, especially the heavy castings and forgings. In the esr process, the inhomogeneity of ingot long the lengh direction was mainly influenced by various factors such as the thermal conductivity, the temperature of slag pool and the melting power which were associated with the variation of the slag composition. Different steel slag samples were collected to seek the variation of the slag composition. Experimental and theoretical researches of the esr solidification process will be conducted according to the variation of the slag. On the basis of experimental research and data analysis, a model of solidification will be established by the transmission theory and mathematical methods. The model will be analyzed and amended by experiments and test results. The models for the esr solidification of remelting slag with different ingredients will be designed according to the conclusions of the experiments and theoretical analysis to achieve the controllability of electroslag remelting steel quality and provide a theoretical basis for the applications in different electroslag remelting steel production.

电渣重熔技术在特殊钢生产过程中应用广泛，但近年来电渣锭，特别是大型铸锻件沿长度方向的不均匀已经成为限制其品质提升的关键问题。电渣重熔过程中，熔渣成分不断变化导致其导热性能、渣池温度、冶炼功率等一系列变化，是造成电渣锭长度方向的不均匀主要原因之一。从不同渣系钢厂采集渣样，并对其进行理论分析，探索熔渣成分变化规律。将熔渣成分变化规律引入电渣重熔钢锭凝固过程，进行实验和理论研究。在实验研究及数据分析的基础上，结合三传理论和数学模拟方法建立凝固数学模型，并通过实验及钢厂成品钢检测结果对其进行检验和修正。根据实验及模型分析的结论，设计针对不同熔渣成分的电渣重熔凝固理论模型，为工程应用中不同电渣重熔钢的生产提供理论依据，实现电渣锭质量均匀化的可控性。

电渣重熔技术特别是大型铸锻件沿长度方向的不均匀是限制其品质提升的关键问题。电渣重熔过程中，熔渣成分不断变化导致其导热性能、渣池温度、冶炼功率等一系列的变化，是造成电渣锭长度方向质量不均匀的主要原因之一。本研究以ANF-6渣系为主要渣系，针对钢种成分为0Cr13Ni5Mo的约25t大钢锭，采用企业调研、实验研究和数学模拟相结合的研究方法，通过对渣皮进行XRD、SEM、XRF、显微镜等分析，明确了大型钢锭熔渣、渣皮成分的变化规律；针对冶炼过程渣系成分变化对夹杂物的影响作了相应的研究；基于熔渣成分变化引起的物化参数的变化，建立了大型钢锭电渣重熔数学模型，探索了大型钢锭与小钢锭电渣重熔过程中温度场、电场分布的不同变化情况。研究结果表明，与小钢锭相比，大型钢锭重熔过程中渣皮分层更为明显。渣皮由钢锭底部至顶部呈现明显的分层规律。渣皮、渣池物化参数在冶炼过程中发生规律性变化，影响钢锭凝固温度场、电场分布，进而影响大型钢锭质量。本研究为电渣重熔相关工艺过程和产品质量控制奠定理论基础，提供科学依据。