Erprobung von Austenit-Ferrit-Verbindungen der Werkstoffe X 3 CrNiMoN 17 13 (1.4910) und X 10 CrMoVNb 9 1 (1.4903) für den Einsatz in modernen Hochtemperaturkraftwerken

Conventional coal-fired power plants with steam temperatures over 560 °C require superheater systems of austenitic materials (e.g. 1.4910) in the steam generator. Since the high-pressure pipework is manufactured from ferritic-martensitic material (e.g. 1.4903). more or less numerous austenite-ferrite-compound are necessary according to each type of design. Three years ago, tests commenced on compounding P91 and austenite components (tubes and forged bars of the materials 1.4903 and 1.4910) in accordance with the HIP diffusion welding process. Initial tests and appropriate examinations of the seams indicated that excellent mechanical engineering properties are altainable if the whole compound is finally subjected to a heat treatment. Current ISO-stress tests and creep tests with hitherto more than 8000 hours are yielding values which are only slightly below the average values of the steel 1.4903. The HIP process is, however. relatively expensive. As a cost-effective procedure designed for series production. the friction welding process has been tested since the beginning of 1995 at the instigation of VEW. The initial results are to be regarded as satisfactory.