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以超临界汽轮机叶片用1Cr11MoNiW1VNbN不锈钢为研究对象,测试叶片模拟工作温度下拉压疲劳极限的变化规律,用扫描电镜观察试样宏观及微观断口。结果表明,1Cr11MoNiW1VNbN不锈钢试样的疲劳极限随试验温度的变化有明显变化。当试验温度为538、566、593℃时,试验钢的拉压疲劳极限的最大变化量为81 MPa。其疲劳试样宏观断口包括裂纹萌生、裂纹扩展及最终断裂3个阶段,存在明显的裂纹前沿;微观断口具有典型的准解理断口特征。
The supercritical steam turbine blades with 1Cr11MoNiW1VNbN stainless steel as the object of study, leaves under simulated working temperature tensile fatigue limit of variation, the use of scanning electron microscopy specimens macro and micro fracture. The results show that the fatigue limit of 1Cr11MoNiW1VNbN stainless steel specimen changes obviously with the change of test temperature. When the test temperature is 538,566,593 ℃, the maximum change of fatigue limit of the tensile test of the test steel is 81 MPa. The macroscopic fracture of the fatigue specimen includes three stages of crack initiation, crack propagation and final fracture, with obvious crack front. The microscopic fracture has typical quasi-cleavage fracture characteristics.