Y-Y Ma et aL/ Engineering Failure Analysis 47(2015)162-177 163 However, in this event, after only ten months'operation, substantially less than the design lifetime of 30 years, a number of severe fractures occurred on the CwP of thermal power unit 8, as shown in Fig. 2, causing substantial economic losses as well as potential safety problems. By means of visual inspection, it was easy to find that most of the fractures occurred on the weld joints rather than the base materials, just as Fig. 2(a)-(c)show. Material property, manufacturing technology, equip- nt operation, service environment, routine maintenance or other factors, which were the main causes for inducing these abnormal fractures, were urgently investigated. Consequently, a comprehensive failure analysis including a variety of characterization methods was conducted to identify the root cause based on our previous failure analysis experiences 1-9]. 田 1. Appearance and structure of CWP: (a)appearance of SA CWP and(b)structure of the CWP.However, in this event, after only ten months’ operation, substantially less than the design lifetime of 30 years, a number of severe fractures occurred on the CWP of thermal power unit 8, as shown in Fig. 2, causing substantial economic losses as well as potential safety problems. By means of visual inspection, it was easy to find that most of the fractures occurred on the weld joints rather than the base materials, just as Fig. 2(a)–(c) show. Material property, manufacturing technology, equip￾ment operation, service environment, routine maintenance or other factors, which were the main causes for inducing these abnormal fractures, were urgently investigated. Consequently, a comprehensive failure analysis including a variety of characterization methods was conducted to identify the root cause based on our previous failure analysis experiences [1–9]. Fig. 1. Appearance and structure of CWP: (a) appearance of 8A CWP and (b) structure of the CWP. Y.-Y. Ma et al. / Engineering Failure Analysis 47 (2015) 162–177 163