Abstract: Finite element analysis method is taken to analysis the reheat steam pipeline elbow heat stress in ultra supercritical unit, which the results showed that, under the intrinsic pressure load, the higher stress fields focus on intrados surface inside arches place, while outside arching place and other places have lower stress. The highest stress filed appeared corner place 25°～35°of inner arching. therefore, the design of elbow inner arching thickness is very important, and the results provided theory basis for the structure design of elbow.

Key words: elbow, ultra supercritical unit, hot -molding, finite element