The long-term stability of residual stresses in steel

Abstract

There is frequent debate over the long-term stability of calibration specimens. It is an essential component of monitoring, especially for X-ray diffraction equipment used to determine residual stresses. If residual stresses are stable, a second consideration is that the residual stress should not be close to 0 MPa. If such specimens are available for monitoring, it is more sensitive concerning changes. These are key requirements when developing calibration specimens. In this study five specimens were observed, one of them was tested for more than 20 years. The stresses were determined with X-ray diffractometers. In the last four years two different X-ray methods for determination were used. It can be shown that high compressive residual stress does not change in steel if the specimens had no dynamic or static load and were stored under normal laboratory conditions. Article Highlights Finding a material in which compressive residual stress is stable Showing that the stability of compressive residual stress is over a long term The stability of the compressive residual stress is in a great range