| About this Abstract |
| Meeting |
2024 AWS Professional Program
|
| Symposium
|
2024 AWS Professional Program
|
| Presentation Title |
Fracture Toughness Assessment of Over-matched Weld and HAZ Performance in Hydrogen |
| Author(s) |
Jonah Klemm-Toole, Xavier Fross, Zachary Buck, Matthew Connolly |
| On-Site Speaker (Planned) |
Jonah Klemm-Toole |
| Abstract Scope |
Hydrogen has long been desirable as a clean-burning energy carrier, and the international codes and standards communities are beginning to address the effect of hydrogen on pipelines and their welds. Many of the current guidelines for hydrogen service are inherited from existing guidelines on natural gas service. One such guideline found in ASME B31.12 code on Hydrogen Piping and Pipelines is the recommendation to over-match welds in pipelines for hydrogen service. However, hydrogen is well-known to decrease the ductility of steels, and the decrease in the ductility is increasingly severe for higher strength steels, and therefore over-matched welds may perform worse in hydrogen. Here we investigate the effect of high pressure hydrogen gas exposure on the fracture toughness of gas metal arc welds and heat affected zones (HAZs). A collaborative robot controlled Fronius TPS 400i was used to produce v-groove butt joints using ER-70S, ER-80S, and ER-100S filler metals on X70 pipe. Single edge notched tension samples were extracted from the weld metal and HAZs and tested in air and 200 MPa gaseous hydrogen to determine fracture toughness. The results indicate that the presence of gaseous hydrogen significantly decreases toughness in all the welds metals and HAZs evaluated. However, the reduction in fracture toughness was not correlated to the filler material strength, and the welds and HAZs retained toughness above the minimum toughness specified in ASME B31.12. These results support maintaining the current ASME B31.12 guidance to over-match welds intended for hydrogen service. |
| Proceedings Inclusion? |
Undecided |