부산대학교 도서관

The purpose of this project was to assess the reliability of the SP (Small Punch) testing method as an alternative mechanical test technique for evaluation of the residual life and integrity assessment of components in ageing plants. The SP testing technique was applied to the low alloy - 2¼Cr 1Mo V modified ferritic steel widely selected for construction of high temperature components in petrochemical plants. The main two test facilities employed during this project were a SP creep testing rig and a SP tensile rig. These equipments assured good accuracy and repeatability of results. As a key component of the development of the test methodology, a new analytical stress-strain model was based on measurements taken on SP specimens from interrupted tests looking at the different phases of the sample deformation. Its implementation offered an important tool for converting the load normally employed in a SP test to the equivalent state of stress and strain, which defines the material behaviour. This proposed stress-strain model was successfully validated, comparing the SP creep results with the conventional uniaxial creep outcome for the as-received material. Thereafter, such a model was used to assess the potential and the sensitivity of the SP technique for evaluating the degree of damage in the aged material, with special emphasis on hydrogen-aged material. The results illustrate that when combined with an appropriate model the SP creep testing technique was shown to be an appropriate tool for integrity assessment of in-service plant components.