Recent Development of Triple Melt GH4169 Alloy

The breakthrough application of triple melt technology (vacuum induction melting (VIM) + electroslag remelting (ESR) + vacuum arc remelting (VAR)) for fabricating GH4169 alloy facilitated the optimization of the entire production process of GH4169 disks. This paper summarizes the research progress on the chemical composition, triple melting, homogenization treatment, cogging, disk forging, residual stress control, and quality control system of GH4169 alloy. The breakthrough and large-scale application of triple melting technology have resulted in improved purity of the GH4169 alloy and reduced occurrence probability of metallurgical defects. In addition, the microstructural uniformity and yield of forging bars have been improved by the combination of fast (upsetting and drawing) and radial forging. Furthermore, deformations occurring during the machining and operation of GH4169 disks have been reduced using residual stress control technology. Results related to ultrahigh strength, ultralarge scale, high corrosion resistance, and hydrogen embrittlement characteristics of GH4169 alloy are discussed, and potential future research directions are outlined here.