Since the 1930s, with the rapid development of continuous steel strip production and advancements in welding and inspection technologies, the quality of welds has continuously improved. The variety and specifications of welded steel pipes have increased, replacing seamless steel pipes in more and more fields. Welded steel pipes are categorized by the type of weld into straight seam and spiral seam pipes. By production method: process classification - arc weld pipes, resistance weld pipes, (high-frequency, low-frequency) gas weld pipes, and furnace weld pipes.

Smaller diameter welded pipes are typically made with straight seam welding, while larger diameter pipes usually employ spiral welding; they are categorized as round welded pipes and non-standard (square, rectangular, etc.) welded pipes based on the shape of the pipe ends; and as mining fluid conveying welded steel pipes, galvanized welded steel pipes for low-pressure fluid conveyance, belt conveyor roller electric welded steel pipes, etc., according to their materials and applications. The specifications and sizes are sorted from small to large based on the outer diameter multiplied by the wall thickness, as per the current national standards.

Product Standards

Common materials for welded pipes include: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

Welded steel pipes are made from steel plates or strips, and are categorized into furnace-welded pipes, electric-welded (resistance-welded) pipes, and automatic arc-welded pipes due to their different welding processes. They are also divided into two types based on their welding forms: straight seam welded pipes and spiral seam welded pipes. Additionally, they are classified into round welded pipes and special-shaped (square, flat, etc.) welded pipes according to their end shapes. Welded pipes are further categorized into various types based on their materials and applications:

GB/T3091-2008 (Welded Steel Pipe for Low Pressure Fluid Transmission): Primarily used for transporting water, gas, air, oil, heating hot water, or steam, etc., general low-pressure fluids and other pipeline applications. The representative material is: Q235A steel pipe.

GB/T14291-2006 (Mine Fluid Transmission Welded Steel Pipe): Primarily used for straight seam welded steel pipes in mining for compressed air supply, drainage, and shaft gas venting. The representative materials are Q235A and B-grade steel.

GB/T12770-2002 (Welded 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 Stainless Steel Pipe for Fluid Transportation): Mainly used for transporting low-pressure corrosive media. Representative materials include 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.

Additionally, decorative welding stainless steel pipes (GB/T 18705-2002), stainless steel welding pipes for building decoration (JG/T 3030-1995), and welded steel tubes for heat exchangers (YB4103-2000).