Large-diameter LSAW steel pipes refer to straight seam welded steel pipes with an outer diameter of more than 325mm. The diameter of the steel pipes produced by the double-sided submerged arc welding process can reach 2020mm, and the maximum diameter of a single weld can reach 1220mm. This type of steel pipe is usually made of high-quality steel such as Q345B and Q345C. In low-temperature areas, materials such as Q345D and Q345E are used. The production process includes hot rolling, hot coiling, casting and other methods. The specific procedures include bending, seaming, internal welding, external welding, straightening, flattening and other processes to ensure that the product meets the requirements of petrochemical standards.