Proceedings of the Third International Conference on Metals & Hydrogen P47

Effect of hydrogen embrittlement due to cathodic protection on fracture toughness of a Ni-Fe-Cr-Mo-N strain hardened superaustenitic alloy

J.P.S. Porto (1)1 , T. Renck (1)1 , T. Falcade (1)1 , N. Stefansson (2)2 , C.E.F. Kwietniewski (1)1

  • (1) 1

    Physical Metallurgy Laboratory (LAMEF) - PPGE3M/UFRGS, Porto Alegre, Brazil

  • (2) 2

    ATI Oil &Gas, Houston, Tx, USA


The challenges related to the Brazilian pre-salt and deep-water fields have demanded the development of increased performance materials capable of meeting a set of requirements, such as mechanical strength, corrosion resistance, toughness and, at the same time, sufficient resistance to hydrogen embrittlement under cathodic protection. Nickel-based alloys, such as UNS N08830, a novel Ni-Fe-Cr-Mo-N superaustenitic alloy, stands out as candidate material for subsea applications in the strain hardened condition. In fact, this material can achieve yield strength values above 1100MPa with 21% of elongation. In this paper, we evaluate the susceptibility of this nickel based alloy to hydrogen induced stress cracking under cathodic protection using the CTOD methodology. Electron backscatter diffraction and fractography are applied here to explain the results in terms of fracture toughness taking in consideration some of the material’s microstructural features and the micromechanisms of fracture. The results indicated a very promising combination of mechanical strength and fracture toughness under the influence of environmental hydrogen stress cracking.


  • superaustenitic
  • toughness
  • cathodic protection
  • hydrogen embrittlement