Field test results of high strength heat resistant boiler tube materials

摘要

As a field confirmation on actual performance of newly developed high strength boiler tube materials for Ultra Super Critical (USC) power plants, five candidate steels of short length were installed at a coal fired power plant of the ChugokuElectric Power Co. under a five year field test program. Selected materials are 9-12%Cr ferritic steels (NF616 and HCM12) and 18.25%Cr austenitic steels (SUPER304H, NF709 and HR3C). The first removal of the installed samples was done after 1O,149hexposure and each test material was investigated on the stability of microstructure, steam oxidation and various strength properties.In any of the tested materials, practically no change in microstructure, tensile strength or creep rupture strength was caused by the exposure. With ferritic steels, as expected from other studies, a relatively large reduction in impact absorbed energywas noted. In the case of austenitic steels, excellent resistance to steam oxidation was confirmed with the tubes shotblasted inside.Through these field test results, it is being confirmed that newly developed high strength boiler tube materials can be applied successfully not only for USC but also for conventional coal fired boilers.