Quality Classification of Large-Diameter Longitudinal Welded Pipes

The application of large-diameter straight seam welded pipes has become very common in people's lives, so do you know what grades the quality of large-diameter straight seam welded pipes can be divided into?

Generally, the surface of hot-rolled large-diameter longitudinally welded pipe products is FA, and the surface of large-diameter longitudinally welded pipe products after pickling is FB. Cold rolled large diameter longitudinal welded pipe products are FB/FC/FD.

Ordinary large-diameter longitudinal welded pipe products do not require high surface requirements, such as the inner panel of an automobile, with an FB surface. For the outer panels of some cars whose general requirements are not particularly high, use FC. For high-end cars, use FD surface.

Usually, pickled large-diameter longitudinal welded pipe products are FB surface, so they can replace cold-rolled products to make some structural parts.

There are a few fewer processes in the back, which can save costs for the enterprise. Moreover, the iron oxide scale on the surface is removed, and it is easy to weld.

Relatively speaking, compared with hot-rolled products, pickling products are easier to weld. If there is subsequent oiling, painting, etc., it will be easier and the quality will be better.

In addition, the dimensional accuracy is much better than that of hot-rolled products, and the dimensional accuracy is higher than that of hot-rolled large-diameter straight seam welded pipe products. Moreover, the pickling products are flat, the shape of the plate is better, and the unevenness is better. Compared with hot-rolled products, the surface finish is also much better, and the aesthetic level is higher.