Abstract: After a certain plant's HCl catalytic oxidation recovery recycling system was used for a period of time, Ta2.5W tee suffered serious damage and failed. By macroscopic inspection, chemical composition analysis, metallographic structure observation, electron microscopy analysis and numerical simulation of the fluid in the pipe, the failure analysis of the damaged Ta2.5W tee sampling was carried out.The results show that fluid wear is the main reason for the failure of Ta2.5W lining.The flow velocity gradient at the gas intersection is large, forming a turbulent return zone, and the gas continuously impacts and rubs on the inner surface of the pipe to form pores, resulting in surface damage.