Hydrogen might be introduced during fabrication welding or might be taken up from an environment during sour service or cathodic protection. Thus, hydrogen assisted stress corrosion and cold cracking is still a major topic regarding the reliability of welded steel components, as for instance offshore platforms and pipelines. In order to support conclusive testing and life time evaluation of welded steel components, a numerical model for hydrogen assisted cracking has been developed, particularly taking into consideration the geometrical effects of crack propagation on the respective hydrogen distribution alongside and ahead of the crack. Numerical calculations were based on finite element analysis of the hydrogen and stress-strain distribution by using a commercially available
program. The model has been verified experimentally by slow strain rate experiments of supermartensitic stainless steels which are intended to be used more extensively as materials for welded flowlines in North Sea oil and gas production. As first results of such simulations the influence
of the subsurface concentration provided by different H2S saturation levels in the NACE TM 0177-96 standard solution on crack propagation and the effect of crack shape on the hydrogen distribution profile are presented in this contribution.
Keywords: hydrogen assisted cracking, numerical simulation, welded steel components, low carbon martensitic stainless steel, sour service, slow strain rate test, crack propagation.