Spiral pipe, also known as spiral steel pipe or spiral welded pipe , is made by rolling low-carbon structural steel or low-alloy structural steel strip into a tube blank according to a certain helical angle (called forming angle) , and then welding the pipe seam. , which can produce large-diameter steel pipes from narrower strips.

The outer diameter of the spiral tube is about 30 nanometers, the inner diameter is about 10 nanometers, and the pitch between adjacent spirals is about 11 nanometers. Every week of the helical tube is surrounded by 6 nucleosomes, and the H1 histone is located on the inner surface of the helical tube lumen, which plays an important role in maintaining the structure of the helical tube. Helicalization of 10 nm fibers composed of nucleosomes to form 30 nm thick fibers further compresses the DNA length by a factor of 6.
industrial pipe

Spiral pipes are mainly used for oil and natural gas pipelines, and their specifications are expressed by outer diameter * wall thickness. There are single-side welded and double-sided welded spiral pipes, and the welded pipes should ensure that the hydraulic test, the tensile strength of the weld and the cold bending performance meet the regulations.