Development of non-destructive small specimen creep testing techniques

摘要: Having knowledge of the current creep strength service-aged components in high temperature installations such as nuclear power stations, oil refineries and chemical plants is essential for their safe economic operation. Obtaining this may involve use small material samples. These samples be removed from weld regions or component surfaces. Improving specimens testing techniques, whereby a reliable uniaxial minimum strain rate rupture data can obtained, has been major engineering concern last 20 years so. This thesis includes development ring specimen order to allow manufactured tested with various shapes geometries. The shape size available normally dictates shape, e.g., circular elliptical. However, changing leads change conversion factors, which are used convert corresponding data. Therefore, effects geometry different thicknesses, on described work. finite element analyses have assess shear deformation behaviour also determine optimum ii geometry. Nickel base Superalloy 738 steel at 800oC (Bar-257) P91 650oC validate method. Two new sized test thesis, i.e., (i) (Two-bar) specimen, suitable obtaining MSR (ii) notched multiaxial stress state parameter. modeling, loading manufacturing both types Finite two-bar (TBS) dimensions failure time, rate, dimension ratio ranges specimen. The obtain full set constants two materials, typical (as received) P91steel 600oC weak 650oC. results show remarkably good agreement between obtained techniques tests. advantages over existing included.