The production and use of hydrogen in the chemical and transportation industries has increased in recent years in efforts to curb greenhouse gas emissions and to make productive use of industrial waste.&nbsp; For many applications, the preferred storage method for hydrogen is as a pressurized gas in metal-lined pressure vessels.&nbsp; Storage of hydrogen is challenging due to interactions between hydrogen ions and the metallic vessel liner, which can result in embrittlement and hydrogen enhanced localized plasticity.&nbsp; These interactions impact how damage develops in the microstructure prior to cracking and how quickly cracks propagate after initiation.&nbsp; Only the latter has been related to the output from non-destructive testing to affect time in service.&nbsp; &nbsp;In this study, we examine how differences in the pre-cracking fatigue behavior observed in steel loaded in hydrogen rich environments affect measurements of acoustic nonlinearity.&nbsp; &nbsp;&nbsp;For this study, a set of SA-372 Grade J steel compact tensile specimens were cut from a commercial ASME Type II pressure vessel.&nbsp; The specimens were cyclically loaded to induce fatigue damage under two conditions: (1) exposed to ambient air and (2) exposed to pressurized hydrogen gas at 3000 psi.&nbsp; One set of specimens was cycled to 20, 40, 60, and 80% of the number of cycles to crack initiation in each exposure condition.&nbsp; Early stage damage was evaluated using the second harmonic ratio, examined using through-thickness measurements made with commercial piezoelectric transducers and a high-power ultrasonic instrument.&nbsp; &nbsp;The results show differences in the growth of the acoustic nonlinearity parameter in materials exposed to hydrogen, and in the values reached prior to crack initiation.&nbsp; By providing an understanding of how nonlinearity develops in hydrogen-exposed steel, this study provides the first step toward early-fatigue monitoring and life extension in hydrogen infrastructure.

Second Harmonic Generation in Pressure Vessel Steel Fatigued in Hydrogen

Paper Proceedings: https://asmedigitalcollection.asme.org/qnde/QNDE2021/volume/85529

ASME 2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.