Large-diameter straight seam welded steel pipes are widely used in daily life. Do you know what quality grades are available for them?
Generally, hot-rolled large-diameter straight seam welded steel pipes have a surface finish of FA, while pickled large-diameter straight seam welded steel pipes have a finish of FB. Cold-rolled large-diameter straight seam welded steel pipes have finishes of FB/FC/FD.
Ordinary large-diameter straight seam welded steel pipes are used for applications with less stringent surface requirements, such as automotive interior panels, which use FB. For automotive exterior panels with less stringent requirements, FC is used. High-end vehicles use FD.
Pickled large-diameter straight seam welded steel pipes typically have an FB surface, so they can replace cold-rolled products in some structural components.
This reduces the number of subsequent processing steps, saving costs for companies. Furthermore, removing the surface oxide scale makes welding easier.
Comparatively, pickled products are easier to weld than hot-rolled products. Subsequent processes, such as oiling and painting, are even easier and result in better quality.
Furthermore, the dimensional accuracy is significantly better than that of hot-rolled products, especially for large-diameter straight seam welded steel pipes. Pickled products also have a smoother surface, better shape, and lower unevenness. The surface finish is also much better than hot-rolled products, resulting in a more aesthetically pleasing appearance.
Post time: Feb-28-2026