Classification of the quality of large-diameter longitudinally welded pipes

The application of large-diameter longitudinally welded pipes has become very common in people's lives, so do you know what grades the quality of large-diameter longitudinally welded pipes can be divided into? The following will introduce the specific content to you.

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

Ordinary large-diameter straight seam welded pipe products have low surface requirements, such as automobile inner panels, which are surfaced with FB. For the outer panels of some cars whose general requirements are not particularly high, use FC. For high-end cars, use FD surface. Usually, the pickled large diameter straight seam welded pipe products are FB surface, so some structural parts can be made instead of cold rolled products. 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 oiling and painting are followed, it will be easier and the quality will be better. In addition, the dimensional accuracy is much better than that of hot-rolled products. Compared with hot-rolled large-diameter longitudinally welded pipe products, the dimensional accuracy is relatively high. In addition, the pickling product is flat, the plate shape is also better, and the unevenness is better. The surface finish is also much better than that of hot-rolled products, and the aesthetics are higher.