About this Abstract |
Meeting |
Advances in Welding and Additive Manufacturing Research 2022
|
Symposium
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Advances in Welding and Additive Manufacturing Research 2022
|
Presentation Title |
Remaining Lifetime Assessment and Creep Degradation Mechanism Study on a 114,000-hour Service-Aged Forge 91-Pipe 91 Steel Header Weld |
Author(s) |
Yiyu Wang, Wei Zhang, Yanli Wang, John Siefert, Alex Bridges, Steven Kung, Zhili Feng |
On-Site Speaker (Planned) |
Yiyu Wang |
Abstract Scope |
Creep degradation in heat affected zone (HAZ) of 9Cr steel welds has been a major concern for their long-term service applications in fossil fuel power plants. Residual lifetime assessment of welded 9Cr steel steam components is crucial for power plant operation and maintenance. In this talk, we summarize our recent work in assessing remaining lifetime of a SA-182 forge 91 (F91) steel reducer to a SA-335 pipe 91 (P91) steel header, which was in service for 141,000 hours (16 years, 1991-2015). Creep testing of this header weld was conducted using an integrated in-situ high temperature creep digital image correlation (DIC) system. The localized creep strain measured by DIC reveal how creep deformation was preferentially accumulated across highly nonuniform welds. Pre-test and post-test metallurgical characterization with multi-scale microscopy techniques were also conducted to analyze critical metallurgical factors (matrix grain, precipitate, inclusion). Effect of pre-existing creep damages in HAZs from the long-term service on the welds was investigated in detail. A correlation between the measured creep properties and the underly microstructures in HAZs was built. This work provides an insight into creep deformation mechanisms of 9Cr steel welds from another prospective. The DIC testing and characterization data have also been successfully used for developing the integrated computational welding engineering (ICWE) modeling tools for creep lifetime prediction of 9Cr steel welds. |
Proceedings Inclusion? |
Undecided |
Keywords |
Additive Manufacturing, |