Large-diameter butt-joint flange structure

The invention relates to the technical field of large-diameter butt-joint flanges for storage tanks, in particular to a large-diameter butt-joint flange structure. The problem that the stresses of a butt-joint welding seam of a flange and the bottom of a storage tank differ largely between the inner surface and the outer surface by the adoption of a conventional butt-joint flange structure, and thus the bearing capacity of the tank bottom is poor is solved. The large-diameter butt-joint flange structure is characterized by comprising a butt-joint ring (1), a weakening groove (2), a conical reinforcing ring (3) and a butt-joint end (4); the upper end of the conical reinforcing ring (3) is fixedly connected with the butt-joint end (4), and the outer side of the lower end of the conical reinforcing ring is fixedly connected with the weakening groove (2); the butt-joint ring (1) is fixedly connected to the outer side of the weakening groove (2); a butt-joint circular seam (5) is fixedly connected to the outer sid