I estimate that the bulge you mentioned is caused by thermal shrinkage, and the partition edge is concave rather than convex. You can take a big board ruler to measure the flatness, or take a tape measure to see if the size is small. The method is to reduce welding current and welding feet. Four partitions and three or four welding feet are enough. Adopt zone welding and increase fixed support. If it does not affect the support, it will not be taken down. Forming after welding, and heating at the drum with cutting gun or baking gun. It will change anyway.