Automatic welding manufacturing method for large-diameter super-long oil and gas transmission longitudinal submerged arc welded pipe

The invention provides an automatic welding and manufacturing method of a large-diameter ultra-long oil and gas transmission longitudinal submerged arc welding pipe, which comprises the following steps: taking two target steel pipes to be welded, respectively processing grooves at the pipe ends of the two target steel pipes, and connecting the two target steel pipes by adopting an inner aligning device; two target steel pipes are placed on a horizontal rotating roller, and the horizontal rotating roller drives the two target steel pipes to rotate in the circumferential direction; the MAG welding process is adopted, and continuous circumferential pre-welding is conducted in the outer grooves of the two target steel pipes; withdrawing the inner aligning device; the SAW welding technology is adopted, circumferential circumferential welding is synchronously completed on inner and outer seams of two target steel pipes, and efficient and automatic welding of the large-diameter super-long longitudinal submerged arc