CREEP ASSESSMENT OF LARGE SIZE HIGH TEMPERATURE COMPONENTS USING SMALL CREEP TEST SPECIMENS

摘要

Most of the large components in the thermal, traditional and nuclear power plants such as pressurized vessels and pipes are operating at elevated temperatures. These temperatures and stress are high enough for creep to occur. For variety of reasons many of these power plants are now operating beyond their design life time. It is -known fact that as the high temperature components aged the failure rate normally increases as a result of their time dependent material damage. Further running of these components may become un-safe and dangerous in some cases. Therefore, creep assessment of the high temperature components of these plants is essential for their safe operation. Mainly for economic reasons these components have to be creep assessed as they are in service. However, assessing the creep strength for these high temperature components as they are in service, it can be challenging task, especially when these components are operating under extremely high temperature and/or stress. This paper introduces newly invented, small creep test specimens techniques. These new small types of specimens can be used to assess the remaining life times for the high temperature components, using only small material samples. These small material samples can be removed from the operating components surface, without affecting their safe operation. Two of the high temperature materials are used to validate the new testing techniques.