The damaged form of LSAW steel pipe surface

LSAW steel pipe is formed by the surface layer of very thin and strong stability of fine chromium-rich oxide film (protective film), to prevent the continued infiltration of oxygen atoms, to oxidation, and access to anti-corrosion ability. If there is some reason, this film was the constant destruction, air or liquid oxygen or metal atoms will continue to penetrate the iron atom out from the constant analysis of the formation of loose iron oxide, metal surface corrosion will be constantly . This surface film in the form of a lot of damage, more common in everyday life are summarized as follows:

1 LSAW steel pipe surface deposit product with other metals containing dust particles or heterogeneous metal fixtures in the humid air, and stainless steel fixtures between the condensate, the two together into a micro-battery, causing the electric chemical reactions, protective film is damaged, call it that electrochemical corrosion.

2 Straight pipe surface adhesion organic juice (such as vegetables, soup, sputum, etc.), oxygen in the water case, constitutes organic acids, organic acids long is the corrosion of metal surfaces.

3 LSAW steel pipe surface adhesion with acid, alkali, salts (such as a wall decoration lye, lime splash), causing localized corrosion.

4 in a polluted air (which contain a large number of sulfide, carbon dioxide, nitrogen oxide atmosphere), the case of condensed water to form sulfuric acid, nitric acid, acetic acid solution point, cause chemical corrosion.

The Application Range of LSAW

​LSAW steel pipe diameter in the range between 406 ~ 1600mm, in exceptional cases even more, the ratio of wall thickness and diameter of about 0.06 to 0.08. Modern foreign technology can produce pipe up to 100mm wall thickness of pipe.

Industrial production of steel plate or LSAW steel pipe only a few ways, the principle difference is the method of forming steel pipe, steel pipe after forming the follow-up process is basically the same. Methodological principles of forming the weld depends on the distribution of steel, according to the distribution of the pipes to weld two basic forms: straight seam and spiral seam steel pipe. Corresponding to this, straight seam welded pipe production into the production and the production of spiral seam pipe. Straight seam and spiral seam steel pipe the most widely used method is submerged arc welding (SAW), its good quality, high productivity, technology is mature and stable. Currently, straight seam steel pipe widely used abroad following range: air land and sea transport, water and oil trunk pipelines; transport chemicals and chemical products of stainless steel tube; marine industrial structure with a tube; boiler manufacturing and special purpose pipe structural tube.