27 Hydrogen Induced Stress Cracking Susceptibility of Hyper Duplex UNS S33207 Stainless Steel Tube

A study has been carried out in order to verify if the Hyper Duplex Stainless Steel (HDSS) could suffer HISC like its predecessor, the super duplex stainless steel (SDSS). The HDSS tubes in as-received condition were cathodically charged for 160 h in artificial seawater, under tensile stress, using different cathodic currents in each sample. The charged tubes were submitted to tensile test and their susceptibility to Hydrogen Induced Stress Cracking (HISC) was assessed, as well as an examination of fracture surface. Hydrogen-induced phase transformation was studied by XRD. The γ→α’ transformation was the dominant hydrogen-induced phase transformation in HDSS. The HDSS showed a higher resistance against HISC in comparison with the SDSS. In summary, under these conditions, the results show that the HDSS underwent hydrogen embrittlement.