Análise crítica de ensaios de fluência em amostras reduzidas empregados como ferramenta de avaliação de vida residual de aços utilizados em caldeiras térmicas

Abstract

Power plants are operating at higher temperatures and pressures to meet the increasing electricity demand, resulting in a higher materials creep damage. The damage evaluation requires materials removal to perform creep tests. This procedure is often unfeasible, as it requires repairs that can cause significant damage to the component mechanical properties, in addition to raising the evaluation cost. Small specimens creep test come as an important tool for the power plant components evaluation, since the removal of these samples does not cause damage to the structure. The objective of this work is to validate creep tests with small size specimens as a tool for evaluating the residual life of power plant steels. In addition, small punch creep tests were also carried out in order to consolidate the knowledge about this new technique efficiency. The results showed that the use of small size uniaxial creep tests results in a reliable determination of the material’s creep life. The small punch creep tests results presented some correlation with the conventional one, however, requiring a larger number of samples to validate it. This test is, however, promising and tends to be in the near future an important tool in the creep life evaluation of components operating at high temperatures.