| About this Abstract |
| Meeting |
2024 AWS Professional Program
|
| Symposium
|
2024 AWS Professional Program
|
| Presentation Title |
Strain Age Cracking of Arc Welded Ni-Base Superalloy Laser-Powder Bed Fusion Components |
| Author(s) |
Timothy Pickle, Abdelrahman Abdelmotagaly, Evan Perri, Benjamin Rafferty, Jeremy Iten, Chad Augustine, Zhenzhen Yu |
| On-Site Speaker (Planned) |
Timothy Pickle |
| Abstract Scope |
Laser-powder bed fusion (L-PBF) additive manufactured (AM) nickel superalloys provide precise products for supercritical carbon dioxide (sCO2) primary heat exchanger (PHX) components in concentrating solar power (CSP) plants. Inconel 740H and Haynes 282 alloys exhibit substantial creep and corrosion resistance, and therefore are considered as candidates for PHX components withstanding service temperatures up to 760°C. In design, arc welding of L-PBF components may be necessary. However, strain aging cracking (SAC) could potentially occur during aging post weld heat treatment (PWHT) at 790-840°C due to the competition between aging of γ’, bulk stress relaxation, and localized plastic strain accumulation along precipitate free zones (PFZs). In this work, a GleebleŽ 3500 thermomechanical physical simulator is used to evaluate SAC susceptibility of L-PBF AM Inconel 740H and Haynes 282 components and their arc welds prepared by gas tungsten arc welding (GTAW). The impacts of printing orientation, heating rate and initial stress/strain conditions on SAC susceptibility are evaluated with an 800°C test temperature. Conventional wrought-to-wrought Haynes 282 plate GTA welds are made to establish a basis for SAC comparison between L-PBF and wrought cross welded specimens. It is found that the vertical print orientation sustains higher stresses and strain compared to horizontal print orientation in both Haynes 282 and Inconel 740H. In the vertical orientation, Haynes 282 contains a higher strain threshold to cracking compared to Inconel 740H prints. Additionally, a c-curve trend is identified in the time-to-failure as a function of heating rate plot, indicating that specimens heated at intermediate rates fail the fastest. Fast heating rates in general led to greater resistant to cracking even with higher stress upon reaching 800°C. Fractography and metallurgical characterization of secondary cracks are conducted to understand the effects of γ’ strain aging and other secondary, intergranular precipitates on cracking. |
| Proceedings Inclusion? |
Undecided |