Hydrogen Permeation and Trapping Characteristics of Cold-Drawn Pure Iron and Eutectoid Steel Evaluated by Thermal Desorption Spectrometry

摘要

Hydrogen absorption characteristics of pure iron and eutectoid steel cold-drawn and annealed have been evaluated by Thermal Desorption Spectrometry (TDS). The pure iron specimens whose structure is ferrite (alpha), and eutectoid steel specimens whose structure is alpha /Fe_3C lamellae, are produced under various degree of reduction area and under various heat treatment conditions. These specimens absorbed hydrogen in 20 mass percent NH_4SCN solution were measured using TDS. TDS analysis shows that the hydrogen desorption of pure iron has a single peak, while that of eutectoid steel has two peaks. The lower-temperature peak corresponds to hydrogen desorbed from trapping sites of point defects, of clusters, and of dislocations. The higher-temperature peak corresponds to hydrogen desorbed from trapping sites of interface dislocations between the alpha and Fe_3C, and/or of point defects and of dislocations in Fe_3C.