Abstract

Hydrogen embrittlement of steel components is a significant technological challenge, especially in the aerospace industry. Hydrogen is introduced into the steel during production and post-treatment. Trace quantities of hydrogen, as small as one-hundredth of parts per million, have the potential to induce embrittlement. Detection of hydrogen is not feasible by many conventional methods used to detect other elements as a result of its low atomic weight. Implementing a non-destructive method to measure hydrogen levels would greatly enhance the precision of quality control procedures. This study attempts to develop an approach for assessing hydrogen content in 4340 and 300M steel using electrical resistivity measurements. Specimens were charged with hydrogen using the electrochemical method and their hydrogen content was measured using thermal desorption spectroscopy. The change in resistivity was measured before and after hydrogen charging using the four-probe method. The findings reveal that the presence of hydrogen can be detected by the rise in electrical resistivity. To distinguish the impact of hydrogen on electrical resistivity from its effect on steel structure, the recovery of resistivity was measured after hydrogen desorption. The recovery of resistivity showed that hydrogen has an effect on electrical resistivity that is independent of microstructural damage seen in the absence of mechanical loading. This study illustrates that electrical resistivity measurement can potentially serve as the foundation for a novel, rapid, and non-destructive analytical technique for determining hydrogen content in high-strength steel components.