Longitudinal and spiral welded pipe is the main difference between the two different production processes, first of all, the formation of straight seam welded pipe is the first through the molding machine to form hot rolled coil, making it into a cylindrical cylindrical outer surface, and then Welding, welding using the proximity effect or under the flux layer of the arc and skin effect, heating the edge of the tube and make it melt, in the appropriate extrusion cooling forming. Longitudinal submerged arc welded pipe and high-frequency straight seam welded pipe is different from the edge of the tube melting differentiate, the general use of arc melting is called the straight seam submerged arc welded pipe, high frequency straight seam welded pipe is the use of high frequency current melting. Spiral welded pipe production process is first in accordance with the appropriate angle of the spiral low-carbon structural steel and low carbon steel coil into the tube, and then welded seam molding. Spiral submerged arc welded pipe is the main form of spiral welded pipe. Can use the narrow steel billets to produce large diameter steel pipe is the most significant feature of the spiral pipe, widely used in all walks of life in China's gas pipeline construction.
To reduce the coating quality, layer type and the construction of environmental factors on the life of straight seam welded pipe coating life, regular welding of straight pipe to rust. Common methods of descaling are four, namely, pickling, cleaning, spray derusting and tool rust. Pickling is one of the most commonly used methods of derusting, not only as a reprocessing process after sand blasting, but also the surface of the straight seam welded pipe rust, oxide, worn coating completely removed, although this cleaning method can make steel surface roughness and cleanliness are up to standard requirements, but after all, is a chemical cleaning method, the surrounding environment is likely to cause pollution. Straight seam steel pipe cleaning can only be used as an auxiliary means in the anti-corrosion treatment, because the cleaning method can only steel surface dust, grease, and lubricants and other residual organic matter removed, and can not play a preservative effect, as we usually wash their hands , You can clean the surface of the dirt, most of the bacteria still remain in the hand. Professional and technical personnel with steel wire brush and other cleaning tools to polish the surface of the workpiece, this approach is called tool rust, loose rust, welding slag and oxide, etc. can be completely removed, but the steel surface attached to the solid Scale is powerless, can not achieve the standard anti-corrosion effect. Spray derusting is the use of steel grit, steel balls and other high-quality abrasive material through the jet strong centrifugal force to the surface of straight seam steel pipe to spray, not only can effectively remove the surface dirt, rust and oxides, roughness will be abrasive And the longitudinal welded pipe friction under the standard level.
