Abstract: For L415/N08825 bimetallic composite pipe, AWS A5.14 ERNiCrMo-3 welding wire was selected, and the hot wire TIG automatic welding process was studied by changing the bevel angle. The operating performance, microstructure,mechanical properties and intergranular corrosion of the welded joints under different bevel angles were compared and analyzed. The results show that the microstructure of the weld metal is mainly composed of coarse dendritic, cellular or massive austenite and ferrite between the austenite. The microstructure of the heat affected zone is mainly composed of pearlite and polygonal ferrite. The grains are coarse and uneven near the fusion line. The mechanical properties and intergranular corrosion results of the welded joints under different bevel angles all meet the requirements of the designed specifications. From the point of optimizing the welding process and welding cost, 15° U-shaped groove can be selected for on-site welding construction of composite pipes.