220 kV舟山与大陆联网工程2基370 m高塔采用自制大直径钢管与内外圈螺孔法兰T型焊接结构，法兰最大直径2.33 m，钢管最大直径2 m，常规的钢管与法兰焊接制作方法无法保证法兰的焊接变形精度的要求。针对高塔结构特点，采用细丝混合气体保护自动焊接新工艺，包括设置合理的坡口角度、制定焊接顺序、预防变形措施等，进行焊接大直径钢管与内外圈螺孔法兰，可为相关工程设计提供参考。

In the design of domestic transmission high tower, the T-type welded structure of flange with bolt holes on the inner and outer circle and self-made large diameter steel pipe is first applied to two 370 m high towers of 220 kV Zhoushan and mainland power grid connecting project. However, the largest diameter for flange is up to 2.33 m, and for steel pipe up to 2 m. The traditional welding method for flange and steel pipe can not ensure the deformation precision of weld. Therefore, in view of the features of high tower, a new welding process of fine wire mixing gas shield is innovated and adopted, which includes setting reasonable groove angle, making welding sequence, providing measures to resist deformation etc. The results obtained in this paper will provide technical basis for welded structure design and application of large diameter steel pipe and flange in high towers.