Effects of Small Defect and Hydrogen on Fatigue Strength of Weld-Jointed Tube in Austenitic Stainless Steel

Abstract

There was a concern that weld toe and welding defects can be causes of the enhancement of the reduced fatigue strength due to hydrogen. Thus, the effect of hydrogen on the fatigue strength of weld-jointed tubes was evaluated. The welding defects were intentionally produced by incomplete penetration. The materials were SUS304 and SUS316L. Fatigue test was done in 0.6MPa hydrogen gas using hydrogen pre-charged specimens. For both materials, hydrogen caused no reduction in the fatigue strength of the welded specimens even if the fatigue strength was influenced by the stress concentration of the weld toe and there were crack-like welding defects.