Development of prediction method of the reduced fatigue strength at contact part between components that is caused by the effect of hydrogen

氢气是解决能源和全球环境问题的最有前途的手段。然而，氢会降低金属材料的强度。本文提出了一种考虑氢气影响的设计方法，特别是对含接触部件的氢气设备部件进行了设计。首先，表征了接触部分疲劳强度的显著降低。阐明了疲劳强度降低的原因是氢的比磨损和氢对裂纹形核的辅助作用。以断裂力学为基础，通过考虑氢引起疲劳强度降低的机理，建立了含接触的氢气设备部件的设计方法。

Hydrogen is the most promising means of solving the energy and global environment issues. However, hydrogen deteriorates strength of metallic materials. In this study, a design method in which the effect of hydrogenis considered is developed, particularly for the components of hydrogen equipment involving contact part. Firstly, a significant reduction in the fatigue strength of the contact part is characterized. The causes of the reduced fatigue strength, which are the specific wear in hydrogen and the assist of crack nucleation by hydrogen, are then elucidated. Based on fracture mechanics, the design method of the components of hydrogen equipment involving contact is established by considering these mechanisms that hydrogen causes the reduction in fatigue strength.