Effects of Chemical Composition, Ingot diameter and shape on Solidification and Macrosegregation in Large Size Ingots of High Strength Steels

大型锻造块用于制造关键部件，如运输和能源行业的轴和模具。生产这种部件的第一步是铸锭。然而，由于锭的大尺寸，产生化学不均匀区域（宏观偏析），其在随后的热处理或锻造操作期间通常不能被消除，从而导致部件不合格和/或报废。近年来，对更大尺寸的锭（高达100吨）的需求一直在持续增加，因此，对于锭铸造/锻造工业来说，开发允许生产没有或几乎没有宏观偏析的大尺寸锭的方法和途径至关重要。在北美，由于来自新兴制造业国家的激烈竞争以及导致成本增加的新法规，这一问题甚至更为严重。为了实现这一目标，需要更深入地了解材料特性（成分、微观结构等）之间的相互作用。和工艺参数。 这种知识库的制造过程的发展是目前的合作研究与开发（CRD）项目的关键目标。在之前与工业合作伙伴Finkl Steel-Sorel的合作中，产生了非常有趣的结果，为工业合作伙伴带来了显著的进步和节省。在该项目中，工作重点将是研究第一阶段未涉及的参数，将研究结果应用于新合金和铸锭尺寸，并开发新方法，以生产高质量铸锭，并有助于加强工业合作伙伴作为大尺寸铸锭加工世界领导者之一的地位。 将利用先进的测试设备进行实验研究，以开发描述微观结构演变的材料模型。开发的材料模型将被实施到有限元（FE）商业代码，以预测大尺寸铸锭中的局部组织非均匀区和相变特性。研究结果最终将在工业层面得到验证。

Large size forged blocks are used for the manufacturing of critical components such as shafts and dies in transportation and energy industries. The first step in producing such components is ingot casting. However, due to the large size of the ingots, chemically heterogeneous zones (macrosegregation) are produced which often cannot be eliminated during the subsequent heat treatment or forging operations leading to part non conformity and/or rejection. In recent years the demand for larger size ingots (up to 100 tons) has been continuously increasing and therefore it is of critical importance for the ingot casting/forging industry to develop methods and approaches that would allow producing large size ingots with no or little macrosegregation. The problem is even more acute in the North American context, because of the fierce competition from emerging manufacturing countries and new regulations that result in increased costs. To achieve this objective, a more in-depth knowledge of the interactions between material characteristics (composition, microstructure, etc.) and process parameters is required. The development of such knowledge base manufacturing process is the key objective of the present Collaborative Research and Development (CRD) project. In a previous collaboration with the industrial partner, Finkl Steel-Sorel, very interesting results were generated which resulted in significant progresses and savings for the industrial partner. In this project, the work will focus on studying parameters that were not addressed during the first phase, apply the developed findings to new alloys and ingot sizes and develop new methodologies that would allow producing high quality ingots and contribute to strengthening the position of the industrial partner as one of the world leaders in processing of large size ingots. Experimental study using advanced testing equipment will be conducted to develop material models describing the evolution of the microstructure. The developed material models will be implemented into Finite Element (FE) commercial codes to predict local microstructure heterogeneous zones and phase transformation characteristics in large size ingots. The research results will be validated ultimately at the industrial level.