Ultra-large-diameter longitudinal submerged arc welded pipe forming die and forming process thereof

The invention discloses an ultra-large-diameter longitudinal submerged arc welded pipe forming die and a forming process thereof, and relates to the related field of pipeline forming. The ultra-large-diameter longitudinal submerged arc welded pipe forming die comprises a mounting table, a lower die, a radian control mechanism, an arc detection mechanism, a mounting frame, a servo motor, a pressing mechanism, a prediction piece, a force detection mechanism, a steel plate and a chord height dial indicator; a lower die is fixedly connected to the front end of the top of the mounting table, a radian control mechanism is fixedly connected to the top of the lower die, the lower die is arranged in a U shape, an arc detection mechanism is fixedly connected to the right end of a mounting plate at the left end of the lower die, and a mounting frame is fixedly connected to the rear end of the top of the mounting table. The pressure sensing chip is driven to move through the electromagnetic block, then the contact rod ma