Large-diameter sleeve butt welding centralizing device

The utility model discloses a centering device for butt welding of a large-diameter sleeve. The centering device comprises a plurality of positioning plates and at least one locking device, the multiple positioning plates are sequentially connected in a hinged mode, the locking device is arranged between the head positioning plate and the tail positioning plate, and the two ends of the upper sleeve and the two ends of the lower sleeve are connected to form a sleeve connecting seam. The large-diameter casing butt welding centralizing device is arranged on the outer wall of the upper casing and the outer wall of the lower casing which are connected in a surrounding mode, and a welding window is formed in the position, corresponding to a casing connecting seam, of the positioning plate. When the positioning device is used, the positioning plates are connected in a hinged mode, the number of the positioning blocks can be increased or decreased according to the diameter of a sleeve, and the positioning device can