Abstract
Fretting fatigue strength of SUS304 was significantly lower in hydrogen than in air. One of the causes was adhesion between contacting surfaces and formation of small cracks. Therefore, impurities in hydrogen can have influence on fretting fatigue strength in hydrogen. In this study, small amount of oxygen was added to the hydrogen, and then fretting fatigue test of SUS304 was carried out in the mixed gas. The fretting fatigue strength in the mixed gas is in the middle between those in air and in hydrogen. Increase in friction force coefficient was also cause of the reduction of fretting fatigue strength in hydrogen. The friction force coefficient in the mixed gas was similar to that in air. There were oxidized fretting wear particles on the fretted surface tested in the mixed gas. Therefore, the increase in fretting fatigue strength by the addition of small amount of oxygen was achieved by mitigation of the adhesion between contacting surfaces.
