Tube-burst Analysis of SA-213TP437H high Temperature Superheater

A SA-213TP437H high temperature superheater tube burst in a power plant. In this paper, combined with it's runtime environment, macro examination, metallographic examination, electron microscope observation and micro area composition analysis were used to analyze the failure reason of the sample tube. The results show that: Due to the fine grain size of superheater tube, a large number of σ brittle phase are precipitated in the metallographic structure in lower temperature. During long-term running, the tube was affected form low cycle fatigue cracking by temperature stress coursed by the load change of generator set, start and stop and so on., which is a long-term over temperature tube burst. Although it is an example of misuse of ultra-fine grain steel pipe, it is recommend that the power plants should conduct spot-check of grain size for other SA-213TP437H high temperature superheater tube, and eliminate similar dangers of superheater tube burst.