Put Abstract Since the final reheater outlet stub header in fossil power plant is exposed to high temperatures, it is structurally fabricated by dissimilar weld. TP316H and P92 were selected as materials of dissimilar weld joint. However these two materials have a large difference in thermal expansion. Hence IN740H was used as a transition piece material between them.
In this study, creep rupture life was assessed for IN740H and P92 dissimilar weld joint and microstructure was observed. From the result of creep test, it is noted that all test specimens were ruptured at heat affected zone (HAZ) of P92 and creep life was approximately 90% in comparison to that of P92 base metal. And at the fractured region, coarse MC carbides were observed in case of fusion line fracture while in case of Type IV region fracture, grains were fine and coarse MC carbides were not found. In order to assess more accurate creep life, more data acquisition and long-term experimental data are required.