Welded steel pipe, also known as welded pipe, steel pipe with a steel plate or strip after curl forming welded steel. Welded steel pipe production process is simple, high production efficiency, different specifications, less investment in equipment, but the general strength of less than seamless. Again being revised GB709 in said opened flat and are original tablet should be called: Cut sheets and single-rolled steel sheet, also known as welded pipe welded steel pipe, steel pipe with a steel plate or strip after curl forming welded steel. Pipe commonly used material for: Q235A, Q235C, Q235B, 16Mn, 20 #, Q345, L245, L290, X42, X46, X60, X80,0Cr13, 1Cr17,00Cr19Ni11,1Cr18Ni9,0Cr18Ni11Nb like. Pipe Category By Application: divided into general pipe, galvanized pipe, Oxygen pipe, wire casing, metric pipe, roller tube, deep well pump tube, automotive, transformer tubes, welded thin-walled tubes, welded Pipes , scaffolding tubes and spiral welded pipe. Classification according to production method (1) according to process sub - arc welded pipe, ERW pipe (high-frequency, low frequency), gas pipe, stove pipe. (2) by weld points - longitudinally welded pipes, spiral welded pipe. Press the cross-sectional shape classification (1) simple section steel - circular steel pipe, square steel pipe, oval pipe, steel triangular, hexagonal steel, diamond steel, octagonal steel, semi-steel circle, other. (2) complex section steel - equilateral hexagonal steel pipe, five plum-shaped steel, steel double convex, double concave steel, oval-shaped steel, conical steel pipe, corrugated steel pipe, steel case, other. Classification according to thickness: thin steel, thick-walled steel pipe. Press the end of the shape classification: divided into circular pipe and shaped (square, flat, etc.) pipe. Features Pipe Longitudinal production process is simple, high efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than the Longitudinal, can narrow the billet production of large diameter pipe, you can also use the same width of the billet production of different pipe diameters. However, compared with the same length of straight pipe joints, weld length of 30 to 100%, and lower production rate. Therefore, the smaller diameter pipe were powered by straight seam welded, large diameter spiral welded pipe for the most part.