Study on Low Cycle Fatigue Properties at Elevated Temperature of N06230 Alloy Based on Sheet-Funnel Specimen

Sheet-funnel specimens and matched curved sheet fixtures were designed, and low cycle fatigue tests at elevated temperature of 650 ℃ were carried out on domestic and imported N06230 alloy tube sheet-funnel specimens, The cyclic stress amplitude-strain amplitude relation parameter model was established based on test data and energy density equivalent method. The model constants were obtained by finite element method, and the accuracy of the model was verified. The stress amplitude-strain amplitude curves, strain amplitude-life curves and Manson-Coffin law parameters of the two alloy tubes were obtained by the model, and the fatigue properties of the two alloy tubes were compared. The results show that the stress amplitude-strain amplitude curves obtained by the sheet-funnel specimen low cycle fatigue testing data and the determined constants of cycle stress amplitude-strain amplitude relation parameter model was in good agreement with those pre-inputted in finite element analyse, and the fitting goodness was higher than 0.98, indicating that the generalizability and accuracy of the model for predicting the cyclic stress amplitude-strain amplitude relation of materials. The cyclic stress amplitude-strain amplitude curves and fatigue properties of domestic N06230 alloy tubes were close to those of imported tubes.