摘要
轮缘润滑器安装座故检过程中,渗透检测发现T型焊缝处出现宏观裂纹,该结构材料为Q345钢。通过外观检测、裂纹宏观形貌观察、裂纹断口形貌观察、焊接微观组织观察、冲击断口观察等试验,对结构的开裂原因进行分析。试验结果表明:焊接接头微观组织良好,无明显焊接缺陷,可排除由于组织原因引起构件失效的可能;对比裂纹断口形貌与焊缝金属冲击断口形貌,两者存在较大差异,可排除由于承受较大冲击载荷开裂的可能;裂纹微观断口存在大量疲劳条带,表明结构为疲劳开裂;综合考虑裂纹启裂位置的受力情况,可以判定疲劳开裂的原因是承受载荷部位的应力集中问题。
A macro crack was found in T weld joint via liquid penetrating test during the failure checking process of the flange lubricator mounting base. The structure is made of Q345 steel. In order to find the cause of failure, some tests were performed, including appearance inspection of failure structure, macrocrack observation, fracture surface observation, microstructure examination, and impact fracture observation. The testing results indicate that the microstructure of welding joints have no weld defects. Obvious differences were found between the fracture morphology of the failed structure and the impact fracture morphology of weld zone. Fatigue striations at the fracture show that the failure mode is fatigue fracture. Considering the stress distribution of weld structure, it can be assumed that the cracking cause is stress concentration.
出处
《失效分析与预防》
2016年第5期322-326,334,共6页
Failure Analysis and Prevention
关键词
轮缘润滑器
安装座
失效原因
疲劳开裂
应力集中
flange lubricator
mounting base
failure cause
fatigue cracking
stress concentration
