Key Manufacturing Technologies for a 650 ℃-Class Ultra- large GH4169 Superalloy Turbine Disk for Heavy-duty Gas Turbines

To meet performance requirements of heavy-duty gas turbines for turbine disks with high temperature capability and large dimensions, a key technology study was conducted to address the high complexity and concentrated risks associated with melting, heat treatment, and forging during the fabrication of ultra-large GH4169 superalloy turbine disks. Taking a 650 ℃-class φ2 440 mm GH4169 superalloy turbine disk as the research object, key issues including shrinkage porosity, elemental segregation, harmful phase distribution, microstructural evolution, and cracking damage during vacuum induction melting (VIM), vacuum arc remelting (VAR), stress-relief annealing, homogenization, cogging, and die forging were systematically investigated. By using finite element simulation combined with secondary development, thermodynamic and kinetic modeling, and other methods, the following models and technologies were developed: a prediction model for shrinkage porosity and safe demolding during electrode ingot solidification; a prediction method for element segregation and Laves phase distribution in the VAR process; a stress relief annealing damage model and a stress relaxation model; a homogenization process design model based on Laves phase dissolution and Nb diffusion; and an integrated forging control technology that couples microstructure control, damage control, and load control. The results show that the proposed full-process control strategy can effectively reduce manufacturing risks and optimize the microstructure of disk forgings, providing important technical support for the manufacturing of key components of ultra-large-sized high-temperature alloys. By using this technology, the largest φ2 440 mm super-large GH4169 alloy turbine disk has been successfully fabricated.KG)