论文部分内容阅读
研究了低压汽轮机末级叶片２Ｃｒ１３不锈钢长期服役失效后显微结构和力学性能的变化，与未服役的叶片相比，显微组织中位错密度升高，部分区域位错胞状组织形成，碳化物粒子粗化，低温冲击断口上发现服役叶片中有显微孔洞和裂纹形成．显微结构的变化导致了服役叶片力学性能的改变，屈服强度、循环屈服强度、抗拉强度均有下降，弹性模量略有下降．疲劳性能测试结果表明，疲劳门槛值下降，疲劳裂纹扩展速率增加，而疲劳极限和材料的本质门槛值基本没有变化．这与叶片表面缺陷被加工掉有一定的关系．材料的消振性实验表明，由于显微空洞的形成使材料的消振性在服役后反而升高了．
The microstructure and mechanical properties of 2Cr13 stainless steel after last service failure of low pressure turbine were studied. Compared with the unserviceable blades, the density of dislocation in the microstructure increased, dislocation cells in some areas formed, and carbides Particle coarsening, low temperature impact fracture found in service leaves with micro-holes and cracks formed. The change of microstructure led to the change of mechanical properties of service blades. The yield strength, cyclic yield strength and tensile strength decreased, while the elastic modulus decreased slightly. The fatigue test results show that the fatigue threshold decreases, the fatigue crack growth rate increases, but the fatigue limit and the material’s intrinsic threshold value remain unchanged. This is a certain relationship with the blade surface defects are processed out. Vibration damping experiments show that the formation of micro-cavities makes the anti-vibration properties of the materials increase after service.