热处理对涡轮叶片榫头表面残余应力的影响

Effect of heat treatment on surface residual stress of turbine blade tenon

采用X射线衍射仪分析了服役后的叶片在580℃热处理前、后榫头表面不同位置的残余应力变化情况。结果表明,叶片完成一个服役周期后,除应力最集中的喉部齿底圆角位置,榫头表面其余位置仍然保持了残余压应力状态;580℃退火热处理不会导致榫头表面残余压应力大幅下降,平均降幅小于100 MPa;退火热处理后,喉部齿底圆角应力集中位置表面残余应力由拉应力转变为压应力,是由于热处理过程中材料蠕变以及降温过程产生的热应力共同作用导致的,这一转变对提高叶片重新服役后的安全性具有积极意义。

Surface residual stress of different points on the tenon part of a second-hand turbine blade were tested by X-ray diffraction technique before and after 580 ℃ heat treatment. Comparison results show that, rasidual compressive stress exists in most areas of the tenon surface after a service term, except the stress concentration point in gear bottom circular bead at throat region; 580 ℃ annealing heat treatment dose not cause distinct decline of rasidual compressive stress in most area of turbine blade tenon, the average decreasing amplitude is less than 100 MPa; on the stress concentration point in gear bottom circular bead at throat region, rasidual tensile stress changes to rasidual compressive stress after annealing treatment, it is caused by creep strain during heat treating and thermal stress which emerged in process of cooling. This variety has positive affect for the safety of whole blade in re-commissioning.