Some applications of analytical TEM to the characterisation of high temperature equipment

Much of the high temperature refinery and power generation equipment curren tly in use in Australia is typically quite old. In many cases plant has bee n operating for over 20 years, and in a few cases, for 40 + years. Understa nding and predicting the behaviour of service-exposed equipment, which has operated at high temperatures and pressures for extended periods, requires a detailed understanding of the material microstructures and properties. Re maining life assessment of aged plant brings to bear a raft of techniques t o measure mechanical properties and to look for damage effects. Analytical transmission electron microscopy (AEM), while not a traditional tool for lo oking at such problems, can provide some useful insights into the microstru ctural degradation processes which can occur during service, such as carbid e coarsening, secondary precipitation and transformation. This paper will h ighlight some of the potentially useful information which AEM can provide, along with some of its limitations, with reference to refiner pressure vess els, turbine generating rotors, and superheater outlet headers. (C) 2001 El sevier Science Ltd. All rights reserved.