Abstract: The inclination of the outlet header pipe joint of a certain ultra supercritical boiler resulted in significant deformation of the welded junction after the pipe joint was connected to the serpentine tube group. Considering the long-term service of the furnace tube, an analysis was conducted on the deformation of the welded junction. The results show that there are no defects at the welded junction, the chemical composition is normal, the metallographic twin morphology is complete and clear, and no abnormal structure is found; When the working pressure is not higher than 3.9MPa and the working temperature is not higher than 563 ℃, the structure at the welding junction has passed the strength check and does not affect the normal operation of the pipe joint and the serpentine tube group.

Key words: ultra supercritical bolier, pipe joint inclination, metallographic structure, strength verification