Evaluation of Testing Conditions Effects on the Resistance to Sulfide Stress Cracking

Sulfide stress cracking (SSC) is becoming a more critical issue due to higher levels of H₂S in new reservoirs. 

Furthermore, more severe working conditions in terms of mechanical loads in H₂S reservoirs requires high grade steels with lower SSC resistance than conventional steels grades. 

For that reasons it is of fundamental importance to evaluate the methods used to determine the fracture resistance in sour environment. 

In this work, finite element analysis was used to model the hydrogen concentration in the DCB sample used in the NACE standard method D.  

This model was used together with crack initiation criteria to feed a developed computer program, capable of evaluation crack length evolution with time. 

The evolution of the electrochemical solution- surface system was taken into account trough a variation law with the time adjusted based on experimental results. 

As a result, the instantaneously K_applied, and consequently the K_ISCC, can be estimated. The predictions were compared with experimental testing results in terms of K_applied vs. K_ISCC.