针对某型燃气轮机低压六级后集气腔裂纹故障,分别进行了生产过程检查,焊缝检查及安装应力、焊接残余应力、热应力、振动应力分析。综合分析结果表明：低压六级后集气腔裂纹故障的主要原因为高压前卸荷腔向低压六级放气管与机组发生共振,在共振应力和热应力共同作用下产生高周疲劳,最终导致距离法兰较近的焊缝位置发生开裂；经过结构改进,消除了因管路共振产生的疲劳应力,使故障得以排除；

Regarding the cracks failure in the gas gathering chamber of a gas turbine’s low pressure sixth stage rear, production process inspection, weld inspection, analysis of installation stress, welding residual stress, thermal stress and vibration stress were conducted separately. The comprehensive analysis results indicate that the cracks failure in the gas gathering chamber of a gas turbine’s low pressure sixth stage rear is caused by resonance between the high-pressure font unloading chamber and the low-pressure sixth vent pipe and the unit, high cycle fatigue occurs under the combined action of resonance stress and thermal stress, eventually, cracking occurred at the weld seam location closer to the flange; After structural improvement, the fatigue stress caused by pipeline resonance was eliminated, enabling the fault to be eliminated.

TH133.1