Better materials for constructing electrical power plants, including a variety of alloys, are becoming increasingly important to their operation. The first international conference to address the subject, Alloys in Power Plant Technology, will be held this June in Berlin.
The question of what materials to use in which components of a conventional power plant usually arises when changes in the design or operation are being considered. Materials may include alloys, composites, ceramics, coatings, and linings. All must be resistant to corrosion, have a long service life, be safe to process, and be cost-efficient to produce. Strength is also important in this high-duty environment, where the impacts of startup and shutdown procedures and the effects of cyclic service can reduce material service life.
For example, T24 is a ferritic material used in the membrane walls of thermal power plants with a steam temperature of about 600 degrees C. Above that steam temperature, nickel-based alloys like T91 are probably better choices. But unexpected problems with T24 have occurred during its handling, according to Frank Neumann, head of project and technical support at RWE Technology in Germany. In a lecture, he will describe the damages that have occurred and report on test results and conclusions about the origin and nature of those damages.
Some components require specific manufacturing conditions that must be allowed for by construction engineers. Erik Solomonsson, distribution manager of Sandvik Powdermet in Sweden, will discuss hot isostatic produced components for power plants. During this process, complex components can be produced with powder metallurgy, which avoids complicated welded structures.
Engineers from European Technology Development in Great Britain will talk about repairing thick-walled components of P91 martensitic steel and preventing crack formation. They will also explain how temperatures are controlled in the thermal treatment of the P92 alloy after welding. Thermodynamic modeling plays a major role during this process.
Karl Maile, acting director of the Institute for Materials Testing at the University of Stuttgart and chairman of the conference, will give a talk on high-temperature materials for advanced fossil fuel-fired plants, including testing procedures.
The conference will highlight both the economic and technological considerations for new materials. Topics include load and duty profiles for high-temperature alloys, application areas for innovative material concepts, resource efficiency offered by composite materials, production technologies and joining methods, testing methods and component testability, and load and duty limits relative to power plant load flexibility.