Effects of Hydrogen Gas Environment on Fatigue Strength at 107 cycles in Plain Specimen of Type 316L Stainless Steel

Abstract

In order to clarify the hydrogen effect on the fatigue strength at 10 7 cycles in a plain specimen of type 316L austenitic stainless steel, rotating bending fatigue tests in laboratory air and plane bending fatigue tests in 1.0 MPa dry hydrogen gas and in air at 313 K were carried out. The main results obtained are as follows. The observed fatigue behavior showed that the fatigue strength at 10 7 cycles in both environments is determined by the non-propagation of a fatigue crack of the order of the grain size. Also, the strength at 10 7 cycles in hydrogen gas is slightly higher than that in air. In the region of high-cycle fatigue, the fatigue life in hydrogen gas is longer than that in air, which is mainly caused by the longer crack initiation life in hydrogen gas. The crack propagation life in hydrogen gas is shorter than that in air but has only a small ratio to the fatigue life in this region.

Low Pressure Hydrogen Gas Effect on Extremely Low Fatigue Crack Growth from Small Blind Holes of SUS304 and SUS316L

“…The testing apparatus used in this study was made in our lab in which a fatigue test in a hydrogen gas environment (11) ~ (14) could be carried out. The system consisted of three parts: the bending fatigue testing machine, the chamber for the environment and the Scanning Laser Microscope (SLM) for observations.…”

“…Stainless steels are candidate materials for components which are exposed to hydrogen gas in a hydrogen energy system. However, even in the case of an austenitic stainless steel, which has a high resistance to hydrogen degradation, a certain degree of hydrogen degradation has been reported (1) ~ (14) . Also, for the long term use of about 10~15 years, it is considered that the fatigue limit design is possible for some elements.…”