Creep testing standards and the influence of bending

AbstractFew data appear to be available quantifying the relationship between bending, or off-axis loading, and the high temperature creep properties of industrially important alloys. This paper reviews the literature on the topic and also presents some new experimental evidence showing the influence of bending on the creep properties of IN939 at 850°C.In general, for materials with reasonable ductility i.e. >3%, the amount of bending likely to be encountered due to normal machining tolerances on the testpiece grip ends and loading bar adaptors is not sufficient to cause a significant change in the expected creep life in comparison with the normal scatter attributable to the other testing tolerances e.g. temperature and load.This paper will help address the plea incorporated into the newly revised creep Standard ISO 204 requesting data correlating creep and bending that could provide information for inclusion into a statement of measurement uncertainty.