206 Y Gong et aL/Engineering Failure Analysis 31(2013)203-210 Table 1 Chemical compositions of the failed tube(wt%). C P Mn Ni ailed tube 16.458 1997 ≤075 0.030 ≤0045 ≤20 100-14.0 16.0-18.0 2.0-3.0 (a) Fig. 4. Metallographic structures of the failed tube, 200x(a)"Yin'face, (b)Yang face. 1 CH COOCH3 80 70 CH3Br CSHSCH3 C2H2Br2 CsHe so5566570758 Fig. 5. GC-MS results of the exhaust gas from CTA dryer. Fig 4a and b displayed the metallographic structures of the 'Yin' and the 'Yang' faces respectively of the failed tube both xhibiting typical austenitic structures with average grain size of about 6. However, it should be particularly pointed out that lots of dot-like inclusions existed within the grains, basically composed of MnS and silicon oxides, and would probably act as the initiating sites of localized corrosions when being exposed to aggressive environments [ 12. Although, the material could be regarded qualified in general.Fig. 4a and b displayed the metallographic structures of the ‘Yin’ and the ‘Yang’ faces respectively of the failed tube, both exhibiting typical austenitic structures with average grain size of about 6. However, it should be particularly pointed out that lots of dot-like inclusions existed within the grains, basically composed of MnS and silicon oxides, and would probably act as the initiating sites of localized corrosions when being exposed to aggressive environments [12]. Although, the material could be regarded qualified in general. Table 1 Chemical compositions of the failed tube (wt%). Element C Si S P Mn Ni Cr Mo Failed tube 0.017 0.398 0.007 0.030 1.642 12.158 16.458 1.997 316L 60.03 60.75 60.030 60.045 62.0 10.0–14.0 16.0–18.0 2.0–3.0 Fig. 4. Metallographic structures of the failed tube, 200 (a) ‘Yin’ face, (b) ‘Yang’ face. Fig. 5. GC–MS results of the exhaust gas from CTA dryer. 206 Y. Gong et al. / Engineering Failure Analysis 31 (2013) 203–210