Effect of displacement rate and subcritical crack growth on J-R curves of API X65 steels in sour environment

Fracture tests in sour solution of an API X65 steel for J-R curves determination were performed at different displacement rates. The results indicated a strong dependence of J-R curves on the displacement rate. At low displacement rates the J-R curves were affected by subcritical crack growth. Above a certain displacement rate, incubation time prior to subcritical crack growth was observed, being the experimental J-R curves not affected by this mechanism. A procedure to evaluate the contribution or not of subcritical crack growth to J-R curves of carbon steels in aggressive environments, verified for that specific steel-environment combination, is being proposed.