Welded Steel Pipe is bent with steel or steel plate is round, square and other shapes and then welded into the surface of the seam with the Steel Pipe. The blank used in the welded steel pipe is steel or strip. Since the 1930s, with the rapid development of high-quality strip rolling and the improvement of welding and inspection technology, the quality of welds has been increasing continuously, and the specifications of welded Steel Pipes have been increasing and more and more fields have been replaced. Sewing steel pipe. Welded steel pipe than the cost of Seamless Steel Pipe, high efficiency classification According to the welding method classification According to the welding method can be divided into different arc welding pipe, high frequency or low frequency resistance welded pipe, gas pipe, furnace pipe, Welded steel pipe: for oil drilling and machinery manufacturing industry. Welded pipe: can be used as water and gas pipes, large diameter straight seam welded pipe for high pressure oil and gas transportation; spiral welded pipe for oil and gas transportation, pipe piles, piers and so on. According to the shape of the weld can be divided into straight seam welded pipe and spiral welded pipe straight seam welded pipe: the production process is simple, high production efficiency, low cost, rapid development. Spiral welded pipe: the strength is generally higher than the straight seam welded pipe, with a narrow blank to produce larger diameter pipe, pipe can also use the same width of the production of different diameter pipe. However, compared with the same length of the straight pipe, the weld length increased by 30 to 100%, and the production rate is low. Therefore, the smaller diameter of the pipe are mostly used straight seam welding, large diameter welded pipe are mostly used spiral welding. According to the use of classification by use is divided into general pipe, galvanized pipe, oxygen blowing pipe, wire casing, metric pipe, roller tube, deep well pump, automotive tube, transformer tube, welded thin-walled tube, Spiral welded pipe. General pipe: general pipe used to transport low pressure fluid. Manufactured with Q195A, Q215A, Q235A steel. It can also be made of other mild steel that is easy to weld. Steel pipe to be water pressure, bending, flattening and other experiments, the surface quality has certain requirements, usually delivery length of 4-10m, often require length (or times) delivery. The specifications of the welded pipe are denoted by nominal caliber (mm or inch). Nominal caliber is different from the actual one. The welded pipe is made of ordinary steel pipe and thickened steel pipe according to the stipulated wall thickness. The pipe is divided into two types: pipe end and thread. Galvanized Steel Pipe: In order to improve the corrosion resistance of steel pipe, the general steel pipe (black tube) for galvanizing. Galvanized steel pipe hot galvanized and electric steel zinc two, hot galvanized galvanized layer thickness, galvanized low cost. Oxygen blowing pipe: used for steel blowing oxygen tube, generally with a small diameter welded steel pipe, specifications from 3/8 inch -2 inch eight. Made with 08,10,15,20 or Q195-Q235 steel strip. For the erosion, and some of the aluminizing treatment. Wire casing: also ordinary carbon steel welded steel pipe, used in concrete and various structural distribution works, commonly used nominal diameter from 13-76mm. The wire jacket wall is thinner, mostly coated or galvanized after use, requiring a cold bending test. Metric Welded Tubes: Specially Made in Seamless Tubes, Welded Steel Tubes with Outer Diameter * Wall Thickness, Tropical, Cold Belt Welding with Ordinary Carbon Steel, High Quality Carbon Steel or Puer Low Alloy Steel, or After Tropical Welding And then made by cold dial method. Metric welded pipe can be used for structural furniture, such as drive shaft, or conveying fluid, thin wall used to produce furniture, lamps, etc., to ensure that the strength of steel and bending test. Roller tube: for belt conveyor roller welding steel pipe, generally used Q215, Q235A, B steel and 20 steel, diameter 63.5-219.0mm. On the tube bending, the end to the vertical line with the center line, the oval has certain requirements, the general water pressure and flattening test. Transformer tube: used in the manufacture of transformer heat pipe and other heat exchangers, the use of ordinary carbon steel manufacturing, requiring crushing, flaring, bending, hydraulic test. Steel pipe to the length or double the delivery, the bending degree of steel pipe have certain requirements. Shaped tube: made of ordinary carbon structural steel and 16Mn steel pipe welded square tube, rectangular tube, cap tube, air plastic steel doors and windows with steel pipe, mainly used for agricultural machinery parts, steel windows and so on. Welding thin wall tube: mainly used to make furniture, toys, lamps and so on. In recent years, stainless steel production of thin-walled tube is widely used, senior furniture, decoration, fence and so on. Spiral welded pipe: is low carbon carbon structural steel or low alloy structural steel strip according to a certain helix angle (called forming angle) rolled into a tube, and then welded joints made, it can be narrow Production of large diameter steel pipe. Spiral welded pipe is mainly used for oil and natural gas pipeline, its specifications with outer diameter * wall thickness said. Spiral welded pipe with single-sided welding and double-sided welding, welded pipe should ensure that water pressure test, weld tensile strength and cold bending performance to meet the requirements. According to the end shape classification is divided into circular welded pipe and shaped (square, flat, etc.) welded pipe. According to the different types of pipe and the use of different classification is divided into: low-pressure fluid transmission with Galvanized Welded Steel Pipe. Mainly used for conveying water, gas, air, oil and heating hot water or steam and other general lower pressure fluid and other use pipe. Galvanized welded steel pipe for low pressure fluid delivery. Mainly used to transport water, gas, air, oil and heating hot water or steam and other general lower pressure fluid and other use of the tube. (Mine fluid transport welded steel pipe). Mainly used for mine pressure, drainage, shaft gas with straight seam welded steel pipe. Its representative material Q235A, B grade steel. (Large diameter welded pipe for low pressure fluid delivery). Mainly used for conveying water, sewage, gas, air, heating steam and other low-pressure fluid and other uses. Stainless steel welded steel pipe for mechanical structure. Mainly used in machinery, automobiles, bicycles, furniture, hotels and hotel decoration and other mechanical parts and structural parts. Its representative material 0Cr13,1Cr17,00Cr19Ni11,1Cr18Ni9,0Cr18Ni11Nb and so on. GB / T12771-1991 (stainless steel welded pipe for fluid delivery). Mainly used for conveying low-pressure corrosive media. Representative material is 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2 and so on. (GB / T 18705-2002), stainless steel welded pipe for building decoration (JG / T 3030-1995), large diameter welded steel pipe for low pressure fluid delivery (GB / T 3091-2001), and heat exchanger Welded steel pipe (YB4103-2000). Straight seam welded pipe production process is simple, high production efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the pipe with larger diameter can be produced with the narrow billet. It can also use the same width