光热电站高温部件用347H不锈钢的疲劳性能与寿命预测方法研究OA

To address the problem that the existing local method neglects the stress gradient effect in high-stress regions,leading to insufficient accuracy in fatigue life prediction,structural material 347H stainless steel used for high-temperature components in concentrated solar power plants was taken as the research object.High-temperature fatigue tests were carried out on smooth specimens under strain control and on open-hole plate specimens under stress control,and their high-temperature fatigue behavior was analyzed.On this basis,combined with the Chaboche elastic-plastic constitutive model,the fatigue stress-strain response of the open-hole plate specimens was calculated,and the fatigue life prediction capabilities of the SWT model and the KBM model were comparatively studied based on the critical plane method.The results show that at the test temperature of 565℃,347H stainless steel exhibits cyclic hardening characteristics.The opening significantly weakens the fatigue strength of the high-temperature structure,with the fatigue life at a peak stress of 200 MPa being only 5.7%of that at a peak stress of 120 MPa.The prediction results of the SWT model all fall within the 2×error band,and its prediction capability is superior to that of the KBM model,while the prediction accuracy of the critical plane method is higher than that of the local method.This study can provide a reference for fatigue life assessment of high-temperature components in concentrated solar power plants.