On effect of hydrogen on very high cycle fatigue behaviours of high strength steels

Abstract

In order to analyse the effect of hydrogen on very high cycle fatigue properties, hydrogen was precharged into two high strength steels. The applied stress intensity factor range at the periphery of inclusions before and after being precharged is approximately proportional to the cubic root of inclusion size. In addition, the applied stress intensity factor range at the periphery of inclusions after being precharged was lower compared with uncharged specimens. The additional stress intensity factor range generated by hydrogen ΔK_H is raised after the hydrogen was precharged. A simple prediction equation of S–N curve was proposed by introducing the hydrogen influence factor. The proposed prediction equation can reasonably describe the S–N curves for precharged specimens.

Keywords:

• Very high cycle fatigue
• High strength steels
• Hydrogen
• Inclusion
• S–N curve

The present work was financially supported by the National Natural Science Foundation of China (grant no. 51101094) and Fund project of Technology Development of Shandong Academy of Sciences (grant no. KJHZ 2011-04).