2018 年 2018 巻 63 号 p. 27-39
The theme of this paper is the hydrogen uptake in high-strength steel mainly for spring and stabilizer of automobile, when used in actual use environment and/or corroded in laboratory-simulating accelerated corrosion environment. In addition, this report gives a new interpretation to diffusive hydrogen concentration measured with Gas-Chromatograph-based Thermo-Desorption-Spectroscopy. When hydrogen in corroded steel (bcc-based ferrite, bainite or martensite) is measured after removing corrosion layer, hydrogen signal often appears at 300 to 400℃, in addition to both diffusive hydrogen signal at below 200℃ and non-diffusive hydrogen signal at over 400℃. However, the hydrogen signal at 300 to 400℃ has not been defined correctly, and it has been regarded as a long-standing unclear problem. Through experimental data and evidence, it is shown that the hydrogen peaks at 300 to 400℃ is based on inevitably-remaining deeply-rooted rust of FeOOH which cannot be removed perfectly from corroded steel sample even with a careful hand-polishing. The hydrogen spectrum appearing at around 300 to 400℃ has no relation to both diffusive hydrogen and non-diffusive hydrogen, and it is generated inside Gas Chromatograph, and therefore, it is not involved with hydrogen embrittlement at all.