Accurate measurement of hydrogen in steels is one of the greatest challenges in the
field of applied science. Even though research on hydrogen in steels has been carried out over the last ten decades, very little progress has been made in fundamental
areas because of the lack of a reliable method for measuring hydrogen within a steel.
The hydrogen atom's small size and its one atomic orbit have caused di culties in
applying readily established measuring techniques to measure the simplest atom.
The small size of the hydrogen atom has also made leak proofing the hydrogen measuring systems extremely difficult; thus, most apparatus are vulnerable to leaking.
Additionally, the need to measure extremely small quantities and the high degree of
statistical variation in the measured quantities have made the measured hydrogen
The main task of this research study was to design and construct a new, direct hydrogen measuring device called the Temperature Vacuum Hydrogen System (TVHS) and to explore some higher temperature measurements of hydrogen in steel using this new device.
This thesis provides a study of the direct hydrogen measuring methods available,
the improvements implemented on the standard eudiometer method to improve the method's accuracy and the users' safety, a discussion of the problems faced during the construction and operation of the TVHS, and the solutions applied to mitigate
them. The hydrogen volumes measured using the TVHS at 50, 150, 250, and 350 C in hydrogen charged AISI 1020 steel samples; and temperature-time relationships
for measured hydrogen quantities; an equation to correlate the measured amounts from the TVHS method with the amounts measured using the standard eudiometer
method are also provided in this thesis.
Key findings of the tests carried out using the TVHS were that a significantly
higher amount of hydrogen egressed at 350 C compared to the amounts that egressed
at lower test temperatures and the time durations took longer than expected for
stabilizing the egressed hydrogen amounts. Equations to predict hydrogen amounts
egress from steel samples that are charged with low hydrogen concentrations were
also derived. In addition, a chemical analysis on a steel sample immersed in mercury at low-elevated temperatures for an extended period showed a possibility for hot
mercury to dissolute carbon from the pearlite structure of the steel, leaving the iron in the structure.