PSI - Issue 60

304 Md Rakim et al. / Procedia Structural Integrity 60 (2024) 298–310 Md Rakim et al. / Structural Integrity Procedia 00 (2023) 000 – 000 7 measurements. After regression analysis, the curve looks like in Figs. 3 to 8 and also the values of 1 and 2 have been mentioned in the curves provided. Considering a crack extension of 0.2 mm, an offset line is drawn taking the same slope of . The point at which this offset line will intersect the power law fitting curve, that intersecting value corresponding to J -integral is considered as the elastic-plastic fracture toughness ( J IC ). Thus, the J IC values have been compiled and shown in the below tabulation for all the materials i.e., base (Table 2), weld (Table 3) and forged (Table 4) of alloy 617M at temperature ranges of 27 °C, 650 °C, 710 °C and 750 °C under different aged durations up to 20000 hours.

Table 2: J IC (MPa.mm) value at different temperatures and ageing time for base material Temperature (°C) Ageing Time (Hours) 0 1000 5000

20000 98.692 116.714 201.399 92.588

27

276.705 251.79 242.541 182.747

256.557 245.988 265.355 145.485

196.263 190.371 233.17 186.243

650 710 750

Table 3: J IC (MPa.mm) value at different temperatures and ageing time for weld material Temperature (°C) Ageing Time (Hours) 0 1000 2000

5000

27

255.334 204.302 177.155

223.209 196.187 166.06 110.302

237.53 170.577 168.889 78.686

155.656 147.408 144.624 69.104

650 710 750

97.93

Table 4: J IC (MPa.mm) value at different temperatures and ageing time for forged material Temperature (°C) Ageing Time (Hours) 0 1000 5000

10000

27

373.878 272.277 255.561

210.33 193.78

211.016

------

650 710 750

171.8

142.383 135.966 107.951

171.8

148.22 131.267

------

142.383

4. Discussion of the Results

In the current investigations, the effect of temperature and ageing time on elastic-plastic fracture toughness ( J IC ) has been studied. Figs. 9-14 shows the variation of J IC value of base, weld and forged metals with temperature and