What are the classifications of straight-seam pipes?

　　 Straight-seam pipe What are the product categories? Let’s take a look!

　　1. Straight-seam pipes are classified by welding type: they can be divided into straight-welded pipes and spiral-welded pipes.

　　Longitudinal welded pipe: It features a simple manufacturing process, high production efficiency, low cost, and rapid development.

　　Spiral-welded pipe: Generally exhibits higher strength than straight-seam welded pipe. It can produce welded pipes with larger diameters using narrower blanks, and it can also manufacture welded pipes of varying diameters from blanks of the same width. However, compared with straight pipes of the same length, the weld length is increased by 30% to 100%, and the production speed is lower. Consequently, most small-diameter welded pipes are manufactured using straight seam welding, while most large-diameter welded pipes are produced using spiral seam welding.

　　2. Straight-seam pipes are classified by application into: ordinary welded pipes, galvanized welded pipes, oxygen‑welded pipes, conduit pipes, metric welded pipes, roller‑track pipes, deep‑well pump pipes, automotive pipes, transformer pipes, welded thin‑film pipes, welded formed pipes, and spiral‑welded pipes.

　　Plain welded pipe: Plain welded pipe is used for conveying low-pressure fluids. It can also be manufactured from other easily weldable low-carbon steels. Steel pipes must undergo hydrostatic pressure, bending, and dent‑resistance tests, and their surface quality is subject to specific requirements. Typical delivery lengths range from 4 to 10 meters, with length markings often required. Welded pipes are specified by nominal diameter; they come in two types—plain steel pipe and thick‑walled steel pipe—depending on the designated wall thickness. Pipes are supplied with either plain ends or threaded ends, as applicable.

　　Galvanized steel pipe: To enhance the corrosion resistance of steel pipes, ordinary black steel pipes are galvanized. Galvanized steel pipes are classified into hot-dip galvanized and electro-galvanized types; hot-dip galvanizing provides a thicker zinc coating, while electro-galvanizing is more cost-effective.

　　Oxygen welding pipes: Used as oxygen blowers in steelmaking, they are typically small-diameter welded steel tubes with diameters ranging from 3/8 inch to 2 inches. To prevent corrosion, some are aluminum‑treated.

　　Electrical conduit: Ordinary carbon steel welded steel pipe, used in concrete and various structural distribution applications, with common nominal diameters ranging from 13 to 76 mm. Electrical conduits have relatively thin walls; most are coated or galvanized before use and must pass cold‑forming tests.

　　Metric welded steel pipes: These are supplied in the form of seamless tubes, designated by their outer diameter × wall thickness in millimeters. They are manufactured from ordinary carbon steel, high‑quality carbon steel, or low‑alloy steel, using either hot‑rolled or cold‑rolled welding processes, or by cold‑rolling after hot‑rolled welding. Metric welded pipes are classified as either heavy‑walled or thin‑walled; the former are typically used for structural components such as drive shafts or fluid‑conveying applications, while the latter are employed in the fabrication of furniture, lighting fixtures, and similar products. In all cases, the pipe must meet specified requirements for tensile strength and bend‑test performance.

　　Roller tubes: welded steel pipes used for conveyor roller assemblies, with diameters ranging from 63.5 to 219.0 mm. The pipe must exhibit minimal curvature, end faces perpendicular to the centerline, and meet specified ovality tolerances; hydrostatic pressure and flattening tests are typically performed.

　　Transformer tubes: Used for manufacturing transformer heating tubes and other heat exchangers, they are made from ordinary carbon steel and must undergo flattening, flaring, bending, and hydraulic testing. Steel tubes are delivered either as cut lengths or in coil form, with specific requirements regarding tube curvature.

　　Welded thin-walled tubes are primarily used in the manufacture of furniture, toys, lighting fixtures, and more. In recent years, thin-walled tubes made from stainless steel strip have seen widespread application, finding use in high-end furniture, decorative elements, fencing, and other areas.

　　Spiral welded pipe is manufactured by rolling low-carbon structural steel or low-alloy structural steel strips into a helical shape at a specified helix angle and then welding the seam. Narrow strips can be used to produce large-diameter pipes. Spiral welded pipes are primarily employed for oil and natural gas transmission pipelines, with their dimensions expressed as outer diameter × wall thickness.

　　3. Classification based on the final form

　　They are classified into circular welded pipes and specially shaped welded pipes (such as square, flat, etc.).