The residual stress distribution strengthened by cold expansion of hole bushing plays an important role in achieving excellent extrusion effect, while the material of compressed part and the interference value have a significant impact on the distribution of extrusion residual stress. According to the theory of non-linear contact friction,a three-dimensional finite element model based on cold expansion strengthening of compression bushing was established. The tangential residual stress distribution of lug was obtained with the simulation model in terms of various materials,TB6 titanium alloy,7050 aluminum alloy and TC4 titanium alloy. The model and simulation results were validated with the experiments of residual stress testing. Moreover,the influence of interference value on the residual stress state in cold extrusion strengthening was also explored. Results also revealed the distribution of tangential residual stress of the squeezed surface,the middle surface,the expansion surface and the bushing thickness direction. It is shown from the research results that the residual stress is unevenly distributed along the thickness of the hole wall after cold expansion and the tangential residual compressive stress has the widest distribution area in the middle surface. The increase of the interference value can expand the distribution range of compressive stress to some extent and increase the value of regional compressive stress. However,the increase of the interference value can also produce partial tension stress,leading to wrinkle effect. Under the same extrusion conditions,the tangential residual compressive stress produced by cold extrusion of TB6 titanium alloy lug has obvious advantages in stress value and distribution area. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.
