轮斗减速机输入轴低应力旋转弯曲疲劳断裂原因分析  

Reason Analysis on Low Stress Rotation Bending Fatigue Fracture of Wheel Bucket Reducer Input Shaft

作　　者：张斌[1] 陈锐[1] 彭以俭 

机构地区：[1]国网冀北电力有限公司电力科学研究院(华北电力科学研究院有限责任公司),北京100045 [2]神华国华国际电力股份有限公司北京热电分公司,北京100025

出　　处：《华北电力技术》2015年第7期61-66,共6页North China Electric Power

摘　　要：某电厂2号轮斗减速机输入轴在运行了7 590 h后断裂,通过断轴的宏观形貌、化学成分、机械性能、金相组织和扫描电镜及能谱结果进行了分析。发现该轴中硫元素严重超标,并在基体上可见大量硫化物,且在应力作用下硫化物与基体发生脱落,从而得出该轴断裂的原因是由于硫化物,在轴高速旋转产生离心力和液力耦合器自重形成的弯曲应力综合作用下,进一步形成孔洞,并诱发微裂纹,从而导致发生了低应力旋转弯曲疲劳断裂。The No. 2 wheel bucket reducer input shaft in a power plant fractured after a run of 7 590 hours. The bro- ken shaft macro morphology, chemical composition, mechanical performance, metallographic structure, scanning elec- tron microscopy and energy spectrum results were analyzed. Excessive sulfur content was found in the shaft and large amount of sulfide can be seen. Under the action of the stress, the sulfide was dropping off,thus it is concluded that the shaft fracture was because of the sulfide. Under the combining effect of centrifugal force of high speed rotation of shaft and the self weight bending stress of hydraulic coupler, a hole was formed, leading to cracking, and then low stress rotating bending fatigue fracture.

关 键 词：轴 应力集中 硫化物 低应力 旋转弯曲疲劳 

分 类 号：TG457.25[金属学及工艺—焊接] TF704.7[冶金工程—钢铁冶金]