Suppression of hydrogen invasion into austenitic stainless steel by means of cavitation peening

Abstract

It has been demonstrated in the present paper that compressive residual stress introduced by cavitation peening can prevent hydrogen invasion into surface of austenitic stainless steel JIS SUS316L. The specimen was treated by cavitation peening employing a cavitating jet in air. After that, the residual stress measurement was performed using an X-ray diffraction analysis with 2D method. Then the surface was catholically charged with hydrogen. Hydrogen content was evaluated by a thermal desorption analysis using a gas chromatography. The obtained results show the compressive residual stress reduces hydrogen content by 85 % when the compressive residual stress is 378 MPa. The hydrogen content decreases along with increase in the compressive residual stress. Considering a profile of the compressive residual stress with respect to depth from the surface, suppressive effect on hydrogen invasion and area of compressive residual stress in depth direction has a strong correlation whose correlation coefficient is 0.997 and the probability of uncorrected is less than 0.1 %.