SUP9稳定杆台架试验失效分析

Failure Analysis of SUP9 Stability Bar in Bench Test

采用宏观分析、电镜及金相显微镜分析的方法,对SUP9稳定杆台架试验失效的样件进行取样检验和分析。结果表明:SUP9稳定杆样件断口的裂纹源位于稳定杆弯转处内侧。裂纹源在样件的局部边缘,裂纹源位置外表面有明显压痕。裂纹源位置局部剥落形成凹坑,凹坑底部少量微裂纹,微裂纹深20~200μm。裂纹内局部被氧化,有氧化铁,腐蚀后裂纹附近未发现非金属夹杂物及脱碳现象,微裂纹处可见明显的组织流变,表明SUP9稳定杆失效与材料本身无关,是热处理后稳定杆表面局部位置受到外力挤压变形,在台架试验过程中应力集中形成裂纹源,造成稳定杆断裂失效。

By means of macroscopic analysis,electron microscope and metallographic microscope analysis,the samples of SUP9 stability bar failed in bench test are sampled and analyzed.The results show that the crack source of the fracture surface of SUP9 stabilizer bar is located in the inner side of the corner of the stabilizer bar.The crack source is at the local edge of the sample,and there is an obvious indentation on the outer surface of the crack source.A few micro-cracks were found at the bottom of the pit,and the depth of the micro-cracks is about 20-200μm.No non-metallic inclusions and decarburization are found in the vicinity of the crack after corrosion,and obvious microstructure rheology is observed in the micro-crack,which indicates that the failure of SUP9 rod was not related to the material itself,after heat treatment,the local surface of the stabilizing rod is compressed and deformed by external force,and the stress concentration forms the crack source during the bench test,which results in the fracture failure of the stabilizing rod.