LSAW Steel Pipe A Brief Introdction
LSAW steel pipe a brief introdction
LSAW steel pipe is a professional expression term for straight seam submerged arc welded steel pipe. LSAW steel pipe is a single plate as raw material, the steel plate in the mold or molding machine in the pressure (volume) into a tube, the use of double-sided submerged arc welding and expansion from the production. Its finished product range is wide, the toughness, plasticity, uniformity and compactness of the weld are better, and it has the advantages of large diameter, thick wall, high pressure resistance and low corrosion resistance. In the construction of high-strength, high-quality long-distance oil and gas pipelines, the required steel pipe is mostly large diameter thick-walled submerged arc welded pipe. According to the API standard, in the large oil and gas transmission pipeline, when through the alpine zone, the seabed, the urban population density area 1 class, 2 type area, straight seam submerged arc welded pipe is the only designated tube type.
LSAW steel pipe Submerged arc welding (including submerged arc welding and electroslag welding, etc.) is a kind of arc in the flux layer under the welding method of welding. Its inherent welding quality is stable, welding productivity is high, no arc and dust and so few advantages, making it a pressure vessel, pipe section manufacturing, box beam and other important steel structure in the production of the main welding methods. Although there have been many kinds of efficient, high-quality new welding methods, but the application of submerged arc welding is still no impact. From a variety of welding methods of the proportion of the proportion of deposited metal weight, submerged arc welding about 10%, and has been little for many years.
When the welding wire is determined (usually depending on the welded steel), the matching flux becomes a key material, which directly affects the mechanical properties of the weld metal (especially plasticity and low temperature toughness), crack resistance, weld defect rate And welding productivity. Wire and flux with the weight ratio of welding wire: flux = 1.1 ~ 1.6, depending on the type of welding joints, the type of flux used, welding specifications may be. Compared with the flux, the amount of sintered flux is more economical, about 20% less.
LSAW steel pipe China's use of flux in about 50,000 tons fluctuations, of which 70% is about melting flux, more than non-melting flux. Europe and the United States industrial developed countries to non-smelting-based flux, about 80%, 90% or more, but there are still smelting flux production and sales, melting flux this lasting productivity and its inherent characteristics.