Pipe commonly used information is generally Q235A, Q235B, 0Cr13,1Cr17,00Cr19Ni11,1Cr18Ni9,0Cr18Ni11Nb, 16Mn, 20 #, Q345, L245, L290, X42, X46, X70, X80, etc. Mechanical properties of welded steel pipe should be done and flattening test and flaring test experiments, and standard rules need to be arrived at. Pipe should be able to accept a certain internal pressure, 2.5Mpa pressure test conducted when necessary, insist on a minute without leakage. A method using eddy current testing of alternative hydraulic test. It can be cut to length or multiple length factory. Steel surface quality should be smooth, does not allow folding, cracks, delamination, lap welding and other shortcomings. Across the surface of the pipe wall thickness is not allowed to have a negative error zoned Road, scratches, weld dislocation, burns and scarring and other delicate shortcomings. Permissible wall thickness at the weld seam weld reinforcement thickening and presence. Longitudinal plate or strip produced industrially just several ways, not the same as on the principle that the method for forming a steel pipe, steel pipe after forming the subsequent processing process is basically the same. Depending on the method for forming the weld pipe principle spread, spread by weld steel pipe into two basic forms: Longitudinal and spiral pipe. Accordingly, pipe production into production and produce spiral pipe Longitudinal. Longitudinal and spiral pipe the most widely used method is submerged arc welding (SAW), good quality, high productivity, technology seasoned, stable. North Weihong Xinglong Steel Co. Our main steel profiles; square tubes, rectangular tube, shaped square and rectangular tube, galvanized pipe, galvanized angle steel, galvanized channel, beam, round, flat steel, angle, channel, open flat, checkered, plate, manganese plate, H-shaped steel, seamless tube, pipe, galvanized pipe, seamless pipe, thread, wire and various types of bends, fittings and other quality assurance, price reasonable. Beijing company in good faith, the customer comes first, double surplus cooperation and mutually beneficial business philosophy, emphasizing quality, price and the effective integration of services, as the basis for the foundation of this company, and I hope and your company in a pleasant and cooperative harmonious environment work together to create a better future