Studying the residual stress homogenization and relief in aerospace rolling ring of GH4169 alloy using ageing treatment

Abstract

In the manufacturing process of aerospace large ring parts, a large number of exterior materials are removed, which makes the ring parts become a thin-walled structure with low stiffness. In the actual production process of the aerospace industry, the processing deformation caused by a series of internal and external factors is ubiquitous. The studies show that the main factor causing the machining deformation is the initial residual stress (RS) inside the blank ring. The ring rolling process is accompanied by local severe plastic deformation, resulting in large and uneven RS. The homogenization and reduction of initial RS are of great significance to reduce the adverse effect of machining deformation. The research object in this study is a sizeable GH4169 alloy aerospace rolling ring. First, a long-term natural ageing treatment was designed for homogenizing residual stresses in sizeable GH4169 alloy ring. Second, a finite element model was established to simulate the rolling process and the thermal ageing process. The corresponding rolling and thermal ageing experiments were carried out to verify the simulation results. The purpose of this process is to explore and verify the effect of natural ageing and artificial ageing on homogenizing and reducing the RS in the rolling ring. The results show that the homogenization of RS distribution was enhanced significantly by natural ageing treatment, while the RS magnitudes descended by 15~35%. Combined with the subsequent thermal stress relief, the RS is significantly reduced or even eliminated. This study is of great significance to the homogenization and reduction of RS in large GH4169 alloy ring.