钛 合 金 承 力 孔二 步 挤 压 强 化 数 值 模 拟 与 工 艺 优 化

"Bearing hole-fastener" is a common connection form used in aircrafts. The two-step hole extrusion process, which combines hole strengthening and bushing press fitting, has broad prospects. However, the coupling mechanism of hole fatigue performance of the two subprocesses is not yet clear and the process potential cannot be sufficiently exerted. In addition, due to the hindrance of bushing, it is difficult to carry out surface integrity detections after experiments. Therefore, taking Titanium alloy hole-stainless steel bushing-high speed steel mandrel as the example, a numerical simulation and parameter optimization work of the two-step hole extrusion process is carried out. Firstly, the material properties are tested and a FEM model is established. Secondly, single-factor simulations are carried out to clarify the mechanism of two-step hole extrusion process, and significant influencing factors are screened out and initially optimized. Then, coupling simulations of significant factors are carried out, and prediction equations for the maximum force, mean residual stress and mean deformation are established, with the mean prediction errors of 2.55%, 5.78% and 8.89%, Finally, the independent action mechanism of significant influencing factors is decoupled, and then the final optimized process parameters are achieved. The coupling mechanism of process parameters and the optimized parameter values obtained in this work can be used to guide the implementation of actual process, so as to give full play to the fatigue gain potential of the two-step hole extrusion process.