Welded Pipe Categories: General Welded Pipe, Seam Welded Pipe, Spiral Welded Pipe

Welded steel pipes are those made by bending and deforming steel strips or plates into circular, square, or other shapes and then welding them together, resulting in pipes with seams on the surface. The billets used for welding steel pipes are steel plates or strips.

General Welded Pipe

General welding pipes are used for conveying low-pressure fluids. They are manufactured from steel grades such as Q195A, Q215A, and Q235A. Other easily weldable soft steels can also be used. The pipes must undergo hydrostatic, bending, and flattening tests, with certain surface quality requirements. The standard delivery length is typically 4-10 meters, and it is often required to deliver to a specified length (or multiples thereof). Welding pipe specifications are indicated by nominal diameter (in millimeters or inches), which differs from the actual diameter. Welded pipes come in two types: standard wall thickness and reinforced wall thickness, and are also available with or without threads at the pipe ends.

Seamless Welded Pipe

Process simple, high efficiency, low cost, and rapid development.

Specs: Φ21.3-457.2*1.8-14

Spiral Welded Pipe

Strength is generally higher than that of seamless tubes, allowing larger diameter tubes to be produced from narrower billets, as well as tubes of different diameters from the same width billets. However, compared to tubes of the same length with a longitudinal seam, the weld length increases by 30~100%, and the production speed is slower. Therefore, smaller diameter tubes mostly use longitudinal welding, while larger diameter tubes generally employ spiral welding.

Spiral seam welded steel pipes are divided into two types: automatic submerged arc welding pipes and high-frequency welding pipes.

a. Spiral seam automatic submerged arc welded steel pipes are divided into two categories: Class A and Class B pipes, based on the pressure of the medium transported. Class A pipes are generally made from ordinary carbon steel Q235, Q235F, and low-alloy structural steel 16Mn, while Class B pipes are made from steel grades such as Q235, Q235F, and Q195, and are used as low-pressure fluid conveyance pipes.

b. Spiral Seam High-Frequency Welded Steel Pipe - There is no unified product standard for spiral seam high-frequency welded steel pipes; they are generally manufactured using ordinary carbon steel grades such as Q235, Q235F, and others.

Spec: Φ219-2320*6-22

Standard

GB/T3091-1993 (Galvanized Welded Steel Pipe for Low-Pressure Fluid Transmission). Primarily used for conveying water, gas, air, oil, heating hot water, or steam, and other general low-pressure fluids, as well as for other pipe applications. The representative material is Q235A steel.

GB/T3092-1993 (Galvanized Welded Steel Pipe for Low-Pressure Fluid Transmission). Primarily used for conveying water, gas, air, oil, heating hot water, or steam, and other general low-pressure fluids and for other pipe applications. The representative material is Q235A steel.

GB/T14291-1992 (Mining Fluid Conveyance Welded Steel Pipe). Primarily used for straight seam welded steel pipes in mine ventilation, drainage, and shaft gas venting. The representative material is Q235A, B-grade steel. GB/T14980-1994 (Large Diameter Electric Welded Steel Pipe for Low-Pressure Fluid Conveyance). Mainly used for conveying water, wastewater, gas, air, heating steam, and other low-pressure fluids, as well as other applications. The representative material is Q235A-grade steel.

GB/T12770-1991 (Welded Stainless Steel Tubes for Mechanical Structures). Primarily used in machinery, automobiles, bicycles, furniture, hotel and restaurant decorations, and other mechanical components and structural parts. Representative materials include 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

GB/T12771-1991 (Welded Steel Pipe for Fluid Transmission). Primarily used for transporting low-pressure corrosive media. Representative materials include 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.