Common materials of welded pipe are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.The billet used for welding steel pipe is steel plate or strip steel, which can be divided into furnace welded pipe, electric welding (resistance welding) pipe and automatic arc welding pipe because of its different welding process. Because of the different welding forms, it can be divided into straight seam welded pipe and spiral welded pipe. Because of the shape of its end is divided into circular welded pipe and special shape (square, flat, etc.) welded pipe. Welded pipes can be divided into the following varieties because of their different materials and uses:GB/T3091-2008 (Welded steel pipe for conveying low pressure fluid): Mainly used for conveying water, gas, air, oil and heating hot water or steam and other general low pressure fluid and other purposes. Its representative material is: Q235A steel.GB/T14291-2006 (Welded steel pipe for fluid transportation in mining): mainly used for straight seam welded steel pipe for air pressure, drainage and shaft gas discharge in mining. Its representative material Q235A, B grade steel.GB/T12770-2002 (Welded stainless steel pipe for mechanical structure): Mainly used for machinery, automobile, bicycle, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative material 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb and so on.GB/T12771-1991 (Welded stainless steel pipe for fluid transportation) : Mainly used for conveying low pressure corrosive media. The material is 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.In addition, welding stainless steel pipe for decoration (GB/T 18705-2002), welding stainless steel pipe for architectural decoration (JG/T 3030-1995), and welding steel pipe for heat exchanger (YB4103-2000).Since the 1930s, with the rapid development of continuous rolling production of high quality strip steel and the progress of welding and inspection technology, the quality of weld is constantly improved, the varieties and specifications of welded steel pipe are increasing day by day, and in more and more fields instead of seamless steel pipe. Welded steel pipe is divided into straight welded pipe and spiral welded pipe according to the form of weld. Classification by production method: Process classification - arc welded pipe, resistance welded pipe, (high frequency, low frequency) gas welded pipe, furnace welded pipe.Small diameter welded pipe adopts straight seam welding, large diameter welded pipe adopts spiral welding. According to the shape of the end of the steel pipe is divided into circular welded pipe and special shape (square, rectangular, etc.) welded pipe; According to different materials and uses, it can be divided into welding steel pipe for mining fluid transportation, galvanized welding steel pipe for low pressure fluid transportation, electric welding steel pipe for belt conveyor roller, etc.According to the current national standard in the specification size table, according to the outer diameter * wall thickness from small to large sort.Straight welded pipe production process is simple, high production efficiency, low cost, rapid development. The strength of spiral welded pipe is generally higher than that of straight welded pipe, and welded pipe with larger diameter can be produced with narrower billet, and welded pipe with different diameter can also be produced with billet of the same width. But compared with the same length of straight seam pipe, the weld length is increased by 30~100%, and the production speed is lower.Large diameter or thick welded pipe, generally made of steel billet directly, and small welded pipe thin wall welded pipe only need to be directly welded through the steel strip. It is then simply polished and brushed.Add: Welded pipe is welded with strip steel, so in its original status is not higher than seamless pipe.Raw material unwinding -- leveling -- end shearing and welding -- lofting -- forming -- welding -- internal and external bead removal -- precalibration -- induction heat treatment -- sizing and straightening -- Eddy current testing -- cutting -- hydrostatic inspection -- pickling -- Final inspection (strictly controlled) -- Packaging -- Shipping.Straight welded pipe production process is simple, high production efficiency, low cost, rapid development. The strength of spiral welded pipe is generally higher than that of straight welded pipe, and welded pipe with larger diameter can be produced with narrower billet, and welded pipe with different diameter can also be produced with billet of the same width. But compared with the same length of straight seam pipe, the weld length is increased by 30~100%, and the production speed is lower.The products are widely used in tap water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction, and is one of 20 key products developed in our country.For liquid transportation: water supply, drainage. For gas transportation: gas, steam, liquefied petroleum gas.For structure: for piling pipe, as a bridge; Pipe for wharf, road, building structure, etc.
