Metodologia experimental para determinação de curvas J-R de aços API X65 em meio ácido

Abstract

One of main challenges for fracture mechanics testing in sour environment is related to the methodology development that reduces instrumentation needs as well defines test parameters to minimize test duration. In this work, with the aim to develop an experimental methodology for J-R curves of API steels in aggressive environments, the influence of some test parameters was analyzed for testing in sour environment. During tests with different displacement rates, subcritical crack growth was verified at low displacement rates, which was also corroborated by large crack extensions observed in the fracture surfaces. Above a certain displacement rate, incubation time prior to subcritical crack growth was observed, which indicates that stable and subcritical crack growth mechanisms can be dissociated, allowing the J-R curves evaluation without contribution of subcritical crack growth mechanism. Thus, in this work an experimental procedure for J-R curves determination of carbon steels in aggressive environments, without subcritical crack growth contribution, is being proposed.