末级过热器12Cr2MoWVTiB/TP347H异种钢焊口失效分析

摘要

通过断口宏观形貌、硬度试验、断口微观组织等分析，研究了1025 t／h锅炉末级过热器12Cr2MoWVTiB／TP347H异种钢焊口运行80000 h后的断裂失效特征。结果表明：在应力幅值较高的交变载荷作用下，12Cr2MoWVTiB侧熔合线区域组织较差，同时存在碳迁移倾向，此处最易产生裂纹，导致失效。%The fracture features of the weld bond of 12Cr2MoWVTiB/TP347H dissimilar steel in a final superheater operated for 80 000 hrs in a 1 025 t/h boiler was investigated by fracture macro⁃morphology analysis, hardness test and fracture microstructure analysis. The results showed that under the alternating loads with high stress amplitude, the weld bond at 12Cr2MoWVTiB side was weak, where carbon also tended to migrate. Cracks most easily occur at this place, resulting in failure.