As an important part of steel products, steel pipes are divided into two categories: seamless steel pipe (round) and welded steel pipe (board, band) due to the different manufacturing processes and the shape of the pipes used.
1. Cold -rolled molding steel allows local flexion to have a local flexion, so that the bearing capacity after the pole is flexed; while the hot -rolled steel does not allow local flexion to occur in the cross section.
2. The causes of hot -rolled steel and cold -rolled steel residual stress are different, so the distribution on the cross section is also very different. The residual stress distribution on the cold -curved thin wall section is bent, while the residual stress distribution of hot -rolled steel or welded steel section is a thin film type.
There is not much difference between the two steel pipes in the finished product. Generally, they are manufactured according to standards. There is no difference in mechanical properties. Higher.
The welded steel pipe is also called a welded pipe. It is a steel pipe made of steel plate or steel belt and welded after curling. Welding steel pipe production technology is simple, high production efficiency, many varieties and specifications, and small equipment funds, but generally lower than seamless steel pipes.
The welding steel pipe is divided into straight seam welded pipes and spiral welded pipes in the form of welds. The strength of the spiral tube is generally higher than that of the straight seam welded pipe. It can use a welded pipe with a larger dispenation diameter with a narrower material. It can also use different welded pipes with different width production pipe diameters of the same width. However, compared with the same length of the same length, the length of the weld is increased by 30 ~ 100%, and the production speed is lower. Therefore, most of the smaller -caliber welded pipes are welded with straight seams, and most of the large -caliber welded pipes are mostly spiral welded.
