动力涡轮工作叶片与导向叶片振动疲劳性能差异分析

Analysis on Difference of Vibration Fatigue Properties Between Blade and Vane of Power Turbine

针对某型航改燃气轮机动力涡轮工作叶片与导向叶片振动疲劳性能差异较大、导向叶片疲劳极限较低的现象,开展了表面状态检查、内部冶金质量检查、断口分析、组织分析、叶身取样疲劳性能对比分析等工作。结果表明:工作叶片和导向叶片表面和内部冶金质量均满足标准要求,内部晶粒度和显微疏松等级相当;工作叶片和导向叶片裂纹均为靠近"叶根"进排气边处的疲劳裂纹;导向叶片未采用细晶工艺,叶身表面晶粒较粗;导向叶片使用返回料导致枝晶间组织粗大、局部区域存在针状TCP相。

In view of the phenomenons that the vibration fatigue properties between the blade and the vane were quite different and the fatigue limit of the vane guide blade was low,the surface condition inspection,internal metallurgical quality inspection,fracture analysis,microstructure analysis,and comparative analysis of blade and vane sampling fatigue properties were carried out for an aero-derivative gas turbine.The results show that the surface and internal metallurgical quality of blade and vane meet the standard requirements,and the internal grain size and porosity elimilation grade are equivalent.The cracks of blade and vane are fatigue caused by near the leading and trailing edge of root.The vane does not adopt fine grain process,the surface grain of the vane body is thicker.The use of the return material in the vane leads to the thick inter-dendritic structure and needle like TCP phase in the local area.