The H absorption characteristics of pure Fe, and eutectoid steel, which had been deformed by cold-drawing were studied. Pure Fe with an α-phase structure, and steel specimens with α-phase plus Fe3C structures, were given various degrees of reduction and various heat-treatments. The amounts of H which were absorbed by specimens that were dipped in 20wt%NH4SCN solution were measured by means of thermal desorption spectrometry. This showed that the H evolution rate of pure Fe exhibited only one peak, while that of the eutectoid steel had 2 peaks. Transmission electron microscopic observations suggested that the lower-temperature peak was due to H that was released from trapping sites such as point defects, clustered defects and dislocations in the α phase. The higher-temperature peak was attributed to H that was released from trapping sites such as defects in Fe3C and/or from the disordered interface between α-phase and Fe3C.

Hydrogen Trapping Characteristics of Cold-Drawn Pure Iron and Eutectoid Steel Evaluated by Thermal Desorption Spectrometry. K.Takai, G.Yamauchi, M.Nakamura, M.Nagumo: Journal of the Japan Institute of Metals, 1998, 62[3], 267-75