Status inspection and service life assessment of welded joints between TP304H / SA213 T22 steels of different sort had been carried out by comprehensively using various testing methods.It had been believed that the welded joint between different steel sorts on sampled tube already reached the end of its service life.Based on this result

the welded joints between different steel sorts on high temperature superheater had been completely retrofitted in a planned major repair in April

2004.The welded joints have been allocated in the space of lower temperature at top of the furnace

a voiding tube replacement in large area after occurrence of leakage.