Influence of hydrogen from cathodic protection on the fracture susceptibility of 25%Cr duplex stainless steel – Constant load SENT testing and FE-modelling using hydrogen influenced cohesive zone elements

• Published in: Engineering fracture mechanics Vol. 76; no. 7; pp. 827 - 844
• Main Authors: Olden, Vigdis, Thaulow, Christian, Johnsen, Roy, Østby, Erling, Berstad, Torodd
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2009; Elsevier
• Subjects: Applied sciences; Cohesive zone modelling; Condensed matter: structure, mechanical and thermal properties; Corrosion; Corrosion prevention; Crack growth threshold; Diffusion in solids; Environmental cracking; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Metals. Metallurgy; Physics; Solid mechanics; Stainless steels; Structural and continuum mechanics; Structural assessment; Transport properties of condensed matter (nonelectronic); Environmental cracking; Crack growth threshold; Cohesive zone modelling; Structural assessment; Stainless steels; Cathodic protection; Lower bound; Prestress; Cohesive end; Rupture; Experimental study; Test bar; Modeling; Crack propagation; Alloy steel; Stress intensity factor; Stainless steel; Topography; Hydrogen additions; Impurity diffusion; Dual phase steel; Threshold stress; Hydrogen embrittlement; Crack
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2008.11.011

Laboratory experiments and cohesive zone simulation of Hydrogen Induced Stress Cracking in SENT tests specimens of 25%Cr duplex stainless steel have been performed. A polynomial formulation of the traction separation law and hydrogen dependent critical stress was applied. Best agreement with the experiments was found for an initial critical stress of 2200MPa and a critical separation of 0.005mm. Proposed threshold stress intensity factor and lower bound net section stress is 20MPa√m and 480MPa. High crack growth rates and typical hydrogen influenced fracture topography suggest large influence of the stress and strain in the fracture process zone on the hydrogen diffusion rate.