Hydrogen embrittlement and corrosion fatigue were reviewed and discussed. The necessity of the determination of hydrogen solubility in steel was emphasized in order to discuss the hydrogen embrittlement phenomenon. As for the corrosion fatigue, many typical examples were presented to illustrate that many parameters affect this complicated phenomenon. Most of the discussions were focused on the problems of engineering importance. It was pointed out that the measurement of corrosion current is useful as the criterion for evaluating the strength of corrosion fatigue.
