About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Welding, Joining, and Bonding of Structural Steels
|
| Presentation Title |
Influence of HAZ Subzone Microstructures on the Hydrogen Susceptibility of HSLA Pipeline Steels |
| Author(s) |
Zhenzhen Yu, Lydia Hines, Jackson McCloskey, Chen Ni, Matthew Connolly, May L. Martin, Gregory Ebel, Joe Bundy, Jorge Penso, Andres Acuna, Ravi Menon, Anoop Samant |
| On-Site Speaker (Planned) |
Zhenzhen Yu |
| Abstract Scope |
A lack of understanding persists regarding how individual subzone microstructures within the heat-affected zone (HAZ) of high-strength low-alloy (HSLA) steel fusion welds influence hydrogen susceptibility, due to the difficulty of isolating these narrow regions for bulk mechanical testing. To systematically evaluate the local hydrogen embrittlement resistance of distinct HAZ subzones in X65M and X70M pipeline steels, a methodology integrating Gleeble simulation, finite element modeling, and metallurgical characterization was developed to enable in-hydrogen single-edge bend testing of subsize specimens containing bulk, homogenized representations of coarse-grained (CGHAZ), fine-grained (FGHAZ), intercritical (ICHAZ), and reheated subregions. Fracture toughness tests in 21 MPa gaseous hydrogen revealed that the final thermal cycle dominates hydrogen resistance. Specifically, sequences ending with a CGHAZ cycle (with a peak temperature high than 1300°C) exhibited a statistically significant drop in performance compared to subregions with lower peak temperatures, driven by an upper bainitic microstructure combined with coarse martensite-austenite (M-A) constituents. |
| Proceedings Inclusion? |
Planned: |