Empirical modeling of residual stress profile for multi-axis milling GH4169G

Abstract

The superalloy GH4169G is used to manufacture integral blisks for aero engines. Torsional bending deformation caused by residual stresses from multi-axis machining is one of the major factors contributing to excessive dimensional errors in blisk blade manufacturing. However, few studies have focused on predicting the residual stress profile in multi-axis milling of the superalloy GH4169G. Therefore, in this paper, an empirical model was established to predict the residual stress profile in multi-axis milling of the superalloy GH4169G. First, 36 sets of multi-axis milling experiments were conducted. Then, the residual stress profile was fitted using the Exponential Decay Cosine (EDC) function and the Firefly algorithm (FA) based on the experiment. Support Vector Machine (SVM) was used to establish the mapping relationship between the process parameters and the coefficients of the EDC function. In addition, the effects of process parameters including spindle speed, feed per tooth and tilt inclination angle on surface residual stress, maximum compressive residual stress and residual stress depth were investigated. Finally, the NSGA-III algorithm was used to obtain the recommended process parameters for multi-axis milling of the superalloy GH4169G blades.