F-f. Chen et aL/ Engineering Failure Analysis 37(2014)42-52 able 1 Chemical composition of TAl in-service titanium tube and the standard values(wt). Fe N H Other elements Total of the rest elements Measured values International values 03 ≤0.1 Note: International values are from GB/T 3620. 1-2007titanium and titanium alloy brand and their chemical composition"[8 Fig 3. Metallographic structure of one in-service titanium tube 200x kN Force-displacement curve 12 4. Force-d Table 2 Mechanical properties of in-service titanium tubes. Tensile strength(ab/MPa) Elongation percentage ( Average 327 379 Note: Sample 1 and sample 2 were taken from tubes 2A032012-l and 2A032012-5, 6 in condenser 2A of unit 1Table 1 Chemical composition of TA1 in-service titanium tube and the standard values (wt%). Chemical element Fe C N O H Other elements Total of the rest elements Measured values 0.058 0.012 0.004 0.1 0.0026 – – SB338 values 0.30 0.08 0.03 0.25 0.15 60.1 60.4 International values 0.20 0.08 0.03 0.18 0.015 60.1 60.4 Note: International values are from GB/T 3620.1-2007 ‘‘titanium and titanium alloy brand and their chemical composition’’ [8]. Fig. 3. Metallographic structure of one in-service titanium tube 200. Fig. 4. Force–displacement curve of tensile test sample. Table 2 Mechanical properties of in-service titanium tubes. Item Yielding strength (r0.2/MPa) Tensile strength (rb/MPa) Elongation percentage (d5/%) Sample 1 365 440 37.0 Sample 2 290 450 38.8 Average 327 445 37.9 Note: Sample 1 and sample 2 were taken from tubes 2A032012-1 and 2A032012-5, 6 in condenser 2A of unit 1. 44 F.-J. Chen et al. / Engineering Failure Analysis 37 (2014) 42–52