Processing and microstructure analysis on the precision rotary swaging of inner-stepped aero-engine shaft

Inner-stepped shafts hold an important role in aero-engine design and manufacturing. The high strength of the aeronautical materials makes it difficult to process the shafts. Traditional machining methods especially the drilling processes usually take a lot of time, and manufacturing accuracy such as coaxiality and wall thickness error is hard to control, especially when the aero-engine shaft has a large length/depth-diameter ratio. In this study, a precision rotary swaging process was studied to form the inner-stepped hole. Based on the constructed constitutive model of nickel-based superalloy GH4169, die design analysis was carried out using the finite element method. Experimental results showed good size accuracy within 0.05 tolerance. The hardness increased by less than 16% and the developing compression residual stress could guarantee the mechanical properties of the shaft. The microstructure showed a slight texture after swaging.