Production process of welded steel pipe

Welded steel pipe, also known as welded pipe, is a steel pipe made of Steel Plate or strip steel after crimping and welding, generally with a length of 6 meters.
Commonly used materials for welded pipes are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
The blanks used for welded steel pipes are Steel Plates or strip steel, which are divided into furnace welded pipes, electric welding (resistance welding) pipes and automatic arc welded pipes due to their different welding processes. Because of its different welding forms, it is divided into two types: straight seam welded pipe and spiral welded pipe. Because of its end shape, it is divided into round welded pipe and special-shaped (square, flat, etc.) welded pipe. Due to their different materials and uses, welded pipes are divided into the following varieties:
GB/T3091-2008 (welded steel pipes for low-pressure fluid transportation): mainly used for conveying water, gas, air, oil, heating water or steam and other general low-pressure fluids and other purposes. Its representative material is: Q235A grade steel.
GB/T14291-2006 (welded steel pipes for mine fluid transport): mainly used for straight seam welded steel pipes for mine compressed air, drainage, and shaft discharge gas. Its representative material is Q235A and B grade steel.
GB/T12770-2002 (Stainless Steel welded steel pipe for mechanical structure): mainly used for machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T12771-1991 (stainless steel welded steel pipe for fluid transportation): mainly used for conveying low-pressure corrosive media. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.
In addition, welded Stainless Steel Pipes for decoration (GB/T 18705-2002), welded stainless steel pipes for architectural decoration (JG/T 3030-1995), and welded steel pipes for heat exchangers (YB4103-2000).
The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the welded pipe with a larger diameter can be produced with a narrower billet, and welded pipes with different diameters can be produced with the same width billet. But compared with the straight seam pipe of the same length, the weld length is increased by 30~100%, and the production speed is lower.
Welded pipes with large diameter or thicker diameters are generally directly made of steel billets, while small welded pipes and thin-walled welded pipes only need to be directly welded by steel strips. Then after a simple polishing, brushing on it.
Welded pipe process
Raw material decoiling - leveling - end shearing and welding - looper - forming - welding - inner and outer bead removal - pre-calibration - induction heat treatment - sizing and alignment - eddy current testing - cutting - hydraulic inspection - pickling - final inspection (Strict control) - packaging - shipment.
Features
The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the welded pipe with a larger diameter can be produced with a narrower billet, and welded pipes with different diameters can be produced with the same width billet. But compared with the straight seam pipe of the same length, the weld length is increased by 30~100%, and the production speed is lower.
Application range
The products are widely used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction. It is one of the twenty key products developed by our country.
Used for liquid transportation: water supply and drainage. For gas transportation: gas, steam, liquefied petroleum gas.
For structural purposes: as piling pipes, as bridges; pipes for wharves, roads, building structures, etc.