| Abstract Scope |
To meet the increasing efficiency requirements of heavy-duty gas turbines, it is essential to manufacture larger and more load-bearing superalloy turbine discs, which imposes extremely high demands on both manufacturing equipment and processing technologies. Producing GH4169 (Inconel 718) alloy turbine discs with diameters exceeding 2 meters typically requires electrode input weight exceeding 20 tons, which not only challenges the ultimate capacity of melting equipment but also magnifies potential issues such as porosity, segregation, and cracking during solidification. Meanwhile, homogenization and stress-relief heat treatment necessitate large-scale heating equipment and careful consideration of residual stress elimination, dissolution of Laves phase, reduction of elemental segregation, and cracking risks during heating. During cogging and die forging, ultra-large-tonnage forging presses and hydraulic presses are essential to ensure sufficient equipment load capacity, while also requiring attention to forging penetrability and cracking risks. On the basis of heavy-duty equipment, this study systematically established control models for six critical processes (vacuum induction melting (VIM), vacuum arc remelting (VAR), homogenization, stress-relief heat treatment, cogging, and die forging) to address potential issues in each stage based on actual equipment conditions. By comprehensively considering the interrelationships between equipment capability limits, alloy characteristics, process design, microstructural and cracking tendencies, a reliable basis for process design was obtained and optimized process parameters were extracted under equipment loading constraints, thereby enabling evidence-based optimization of the entire manufacturing route. Finally, a GH4169 superalloy turbine disc forging with Θ2440 mm and a weight of approximately 12 tons was successfully produced. |