Correcting device for deformation of square flange after welding

The utility model relates to a correcting device for deformation of a square flange after welding, which comprises a fixing plate, a push plate is arranged right above the fixing plate, an adjusting mechanism for adjusting the distance between the push plate and the fixing plate is arranged between the push plate and the fixing plate, and four sliding rails are radially arranged on the fixing plate. A pulling claw which extends upwards and is bent towards the center of the fixing plate is connected into each sliding rail in a sliding mode, a pressing plane is arranged on the claw portion of each pulling claw, and the arrangement positions of the four pulling claws on the fixing plate correspond to the four corners of the square flange to be corrected in a one-to-one mode. According to the utility model, the square flange which is deformed after being welded can be reversely deformed, so that the planeness of the flange meets the requirement, and the tail gas postprocessor is ensured not to incline after being