Prediction of the microstructure evolution and hot cracking index in electron beam welding of Inconel 713LC gas turbine blades

西门子加拿大公司是世界上最大的电气工程、能源和 运输业专门从事用于发电的燃气涡轮机发动机。在这些应用中， 在高温下，为了获得高效率和可靠性，材料的选择至关重要。对于这样 在某些应用中，镍基超合金由于其良好的抗蠕变性、抗拉强度和抗氧化性而被使用 阻力西门子特别选择Inconel 713 LC合金制造涡轮机叶片， 在高温下承受拉伸载荷。在对接过程中出现了亟待解决的产业问题 通过电子束焊接（EBW）将涡轮机叶片焊接在涡轮叶片的最佳位置。相关的热输入较低 采用这种焊接工艺，熔合区和热影响区较小，冷却速度快 rates.由于熔凝区的快速凝固，显微组织变得比母材更细小 材料导致局部降低的抗蠕变性。除此之外，产生的高拉伸应力 在冷却过程中，增加了FZ和HAZ中热裂纹的风险。根据焊接操作 在这种情况下，高水平的废品成为公司的一个重要问题。在过去的几年里， 加拿大西门子公司的工程师们已经在电子束焊接的热机械模拟方面投入了大量的精力 过程他们可以模拟焊缝周围材料中的热流，以获得 已知会增加热裂纹风险的温度分布和残余应力。的目的 拟议的研究项目是评估预测的微观结构的演变的可行性， Inconel 713 LC合金在FZ和HAZ中的热裂纹指数，以确定可用于 评估冷却过程中裂纹形成的风险以及这种现象更容易发生的位置 发生.该项目的独创性与这种工艺-微观结构-性能关系有关， 通常存在于用于焊接工艺的商业有限元软件工具中。

Siemens Canada, one of the largest companies in the world in the field of electrical engineering, energy and transportation is specialised in gas turbine engines used for power generation. In such applications at high temperature, the selection of materials is critical in order to obtain high efficiency and reliability. For such applications, nickel-based superalloys are used due to their good creep resistance, tensile strength and oxidation resistance. Siemens selected specifically the Inconel 713LC alloy for the fabrication of turbine blades that are subjected to tensile loading at high temperature. The industrial problem to be solved appears during the joining of turbine blades in the shrouds location by electron beam welding (EBW). The lower heat input associated with this welding process leads to smaller fusion zone (FZ) and heat-affected zone (HAZ) and high cooling rates. As a consequence of fast solidification of the FZ, the microstructure becomes finer than that of the parent material resulting in localised reduced creep resistance. In addition to that, the high tensile stresses generated during cooling increase the risk of hot cracking in the FZ and HAZ. Depending on the welding operational conditions, the high level of rejected parts becomes an important issue for the company. During the last years, the engineers of Siemens Canada have deployed a major effort in the thermomechanical modeling of the EBW process. They could simulate the heat flow in the materials around the weld in order to obtain a map of temperature distribution and residual stresses that are known to increase the risk of hot cracking. The aim of the proposed research project is to evaluate the feasibility to predict the evolution of the microstructure of the Inconel 713LC alloy in the FZ and in the HAZ in order to determine a hot cracking index that could be used to evaluate the risk of crack formation during cooling and the locations where this phenomenon is more prone to occur. The originality of the project is related to this process-microstructure-properties relationship that is not normally present in commercial finite element software tools for welding processes.