摘要
某水电厂大轴联接螺栓材质为S35C钢,大约在服役6.5万h后产生裂纹。利用光学显微镜、扫描电子显微镜、直读光谱仪、能谱分析仪、显微硬度机、拉伸试验机及冲击功试验机等手段,对螺栓宏观、化学成分、硬度、室温力学性能、金相、能谱和电子显微形貌开展了分析试验研究。结果表明,因螺栓为非正常的网状铁素体组织,致使螺栓冲击功明显降低,螺栓基体中某些夹杂物及显微孔洞的存在,使局部应力集中,孔洞在拉应力的作用下随形变过程不断扩大、贯通,最后形成较大的裂纹。
The connection bolt material of turbine's large shaft of a hydropower station is S35C steel and cracking occurred after operation for 65 thousand hours.By means of optical microscope,direct reading spectrometer,spectrum analyzer,microscopic hardness meter,tensile testing machine and impact test machine etc.,the macro feature,chemical composition,hardness,mechanics under indoor temperature,metallic phase,energy spectrum and electronic microscope are researched.The research results show that the bolt structure is abnormal reticular ferrite,which results in obvious decrease of anti-impact function of the bolt;foreign impurity and micro holes are existed in bolt,which results in local stress concentration and the holes become larger and longer under tensile stress action and forming larger cracks in the last.
出处
《人民长江》
北大核心
2012年第23期51-53,共3页
Yangtze River
