EFFECT OF INTERNAL HYDROGEN ON FATIGUE STRENGTH OF TYPE 316 STAINLESS STEEL

The effects of hydrogen embrittlement has been extensively researched, however, relatively little research has been devoted to the effects of internal hydrogen on the fatigue strength of structural metals. This paper examines the effect of internal hydrogen on the fatigue strength of strain-hardened type 316 stainless steel in rotating beam fatigue tests. The tensile properties and high cycle fatigue life of two type 316 stainless steel alloys were studied using thermal precharging to approximate high-pressure hydrogen exposure for long times. Tensile testing was found to be consistent with previous studies using the identical environmental condition. Hydrogen precharging increased the number of cycles to failure by 5 to 10 times compared to non-charged specimens. The basic shape of the S-N curve and the apparent fatigue limit were essentially unchanged by thermal precharging with hydrogen.