Effect of microstructural anisotropy and test pressure on the hydrogen embrittlement of a Hot-Rolled DSS 2205

The excellent anti-corrosion resistance properties of duplex stainless steels (DSS) have made it a great choice material for engineering applications in corrosive environments. But it is still necessary to broaden the knowledge of these materials in hydrogen environments to know its susceptibility to embrittlement and the effects on mechanical properties. This paper focuses on studying the mechanical behaviour of DSS grade 2205 by means of tensile tests in pure hydrogen gas environment at different pressures (in-situ testing), avoiding electrochemical or ex-situ procedures that introduce uncertainties. Standard smooth and notched specimens following ASTM G142 have been used. Specimens have been machined in longitudinal and transversal orientations from a hot-rolled plate to study the anisotropy. The results show the influence of orientation on the mechanical properties. The tests at pressures ranging from 35 bar to 140 bar in hydrogen have a huge impact reducing the mechanical properties of DSS 2205 compared to tests in inert environments. Moreover, the failure mechanisms have been analyzed founding brittle behaviour characteristic of HE.