Session: MF-02-06 Materials for Hydrogen Service (Joint with CS-02 and HT-07) - Hydrogen Exposure Effects

Paper Number: 108285

108285 - Required Soaking Time for Hydrogen Testing 

As the need and demand for clean energy intensifies, there is a push for hydrogen to be transported through legacy oil and gas pipelines or new pipeline builds. Currently, there is limited test data on the impact of these activities on the mechanical properties (fatigue, fracture toughness, crack growth rates, etc.) and life cycle of steel piping. Also, the wide range of steel grades, weld methods, quality of manufacturing, etc. involved with oil and gas pipelines will influence the degree of impact and require a large database of test results. While conducting these test programs, establishing an acceptable H2 soak time that efficiently achieves near steady state conditions with respect to properties of evolution is of the utmost importance.

The purpose of this work was to discern the relative effects of various hydrogen soaking times on the fracture mechanics response of legacy steel pipe.  24 bolt loaded CT samples were machined out of a legacy steel pipe (approximately 0.3-in. WT). Pre-cracking was performed in air with a final deltaK on the order of 15 to 18 ksi-in^0.5 and R ratio of approximately 0.3. The pre-cracked CT samples were bolt loaded to the final Crack Mouth Opening Displacement (CMOD) value to match the stress intensity that was observed on the sample during pre-cracking.

The samples were exposed to 100% H2 at 1,800 psig at room temperature for various soaking times including 1 day, 7 days, 21 days, and 42 days.  Four specimens were exposed to each soak time.  One was tested for diffusible H2 and three were mechanically tested to quantify the effect of H2.

There is very limited data publicly available on diffusion rates / soak times when running tests in gaseous H2 with only ASME B31.12 as conservative guidance. Many H2 scientists, engineers, and researchers have expressed concern regarding this issue. This work will increase the knowledge of an acceptable soak time while testing pipe steels in gaseous H2.

Presenting Author: Jesse Rhodes EWI

Presenting Author Biography: Jesse Rhodes, P.E., is an Applications Engineer in the Structural Integrity group at EWI. He has a B.S. in Materials Science and Engineering from the Ohio State University.

At EWI, he provides mechanical testing and fracture toughness analysis of pipe used for onshore gas transmission, tests additively manufactured pipe with internal sensing capability, and is developing additional capabilities to test materials in Hydrogen environments at high pressures.

Prior to joining EWI, Jesse worked at DNV for 12 years, where he specialized in corrosion research and testing related to complex offshore oil and gas materials applications and flow-assisted corrosion studies. He has designed, developed, and supervised the fabrication of single-phase flow loops systems for these applications.

Authors:

Jesse Rhodes EWI
Tom McGaughy EWI
Joshua James EWI