Tuesday, November 12, 2013

Longitudinal and spiral welded differences and blasting methods

The main difference of longitudinal and spiral welded pipe lies in the two different production processes, the formation of the first Longitudinal molding machine through the first hot rolled coil shape, so that it becomes smooth cylindrical outer surface, and then soldering, welding or the use of a solder layer of the proximity effect of arcing and burning of the skin effect, the edge of the heating tube and melted in a suitable cooled compression molding. LSAW and ERW tube edge is melted in different ways by the distinction, generally called by arc melting LSAW steel pipe and ERW is the use of high-frequency current melted. Spiral welded pipe production process is to follow the appropriate helix angle of the low-carbon low-alloy structural steel and carbon steel coils into the tube, and then seam welded pipe forming. Spiral welded pipe spiral submerged arc welded pipe is the main form. Can narrow the billet production of large diameter spiral steel pipe is the most significant feature is widely used in all walks of life of the gas pipeline construction.

To reduce the quality of the coating, layer type and construction of environmental factors on the life of the coating Longitudinal should be regularly Longitudinal rust. There are four common rust, namely, pickling, cleaning, descaling and tools rust spray. Pickling is the most common ways of rust, sand-blasting not only can be used as a further treatment step after, but also the Longitudinal surface rust, scale, old coatings completely removed, although this cleaning method make steel surface roughness and cleanliness requirements are up to par, but that is a chemical cleaning method, likely to cause pollution of the surrounding environment. Straight seam steel pipes cleaned only as an adjunct to anti-corrosion treatment, because the steel surface cleaning methods can only dust, grease and lubricants and other residual organics removed, and can not play antiseptic effect, as we usually wash Like, you can clean the surface of the dirt, most bacteria are still left in the hand. Professional and technical personnel with a wire brush and other cleaning tools on the surface to be polished, this approach is known tools rust, loose rust, welding slag and oxide so can be completely removed, but for steel surface firmly attached oxide is powerless and can not achieve the standard preservative effect. Jet is the use of grit blasting, steel shot abrasive materials such as high-quality powerful centrifugal force through the jet to jet straight seam steel surface, not only can effectively remove surface dirt, rust and oxides, etc., will be as abrasive roughness Longitudinal friction and achieve the standard required under the action.

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