Arc Welding Tubes
We offer SAW or Submerged Arc Weld, as the name suggests, is a manufacturing method for large diameter Welded Tubes. SAW Tubes are mainly are classified into Helical / Spiral SAW (HSAW) and Longitudinal SAW (LSAW). Generally large diameter tubes from Size 12¾” (324mm) onwards can be manufactured in LSAW construction and Size 16” (406mm) onwards in HSAW construction.
SAW are manufactured as per various standards and specifications like the Indian Standards IS3589,IS1978,IS2129,IS5504 American Standards like ASTM A53, API 5L (up to X80), AWWA C – 200, ASTM A134, A139, A252, A381, A589, A671, A672, A691, A1005, and British Standards BS7191. SAW tubes are usually used by various industries and for various applications viz. Oil & Gas, Hydrocarbon & Process Industry, Water & Sewerage, Piling, Structural or industrial applications like the mining and dredging etc.
Longitudinal Submerged Arc Welding is a specific welding technique used in tubes production where the finished product requires a particularly high wall thickness due to high internal or external pressures.
With this in mind the main applications of LSAW tubes include oil, natural gas, gas, central heating, water supply, sewage treatment and other similar uses.
Steel tubes are long, hollow tubes that are used mainly to convey products from one location to another. They are produced mainly by two distinct manufacturing methods which result in either a welded tube or seamless tube. In both the manufacturing methods, raw steel is first cast into a more workable starting form (slabs, hot billet or flat strip). It is then made into a tube by stretching the hot steel slab/billet out into a seamless tube or forcing the edges of flat steel strip together and sealing them with a weld.
When operational conditions require high wall thickness due to high internal or external pressures, LSAW (Longitudinal Submerged Arc Welding) tubes are commonly the most economical solution.
The LSAW tube diameter range is larger than ERW (Electric resistance welding), normally from 16 inch (406 mm) to 60 inch (1500 mm). Good performances on high pressure resistance, and low-temperature corrosion resistance.
In LSAW tube mills, processing is carried out by cold forming heavy carbon steel plates, the tube pre‐material on which many of the tube properties depend.
The material of LSAW steel tube is unit middle or heavy thickness sheet, coiled in the molding or forming machine, welded by double submerged arc welding and expand the diameter. The specification scope is wide, and have good toughness, ductility, uniformity, compactness, etc.
Longitudinal submerged arc welded (LSAW) tube manufacture process is bending and welding wide steel plates to tube from leveled hot rolled coils by both the JCOE and UOE (the forming process in which the plate like the letter “J”, “C”, “O” or “U” shape, then expansion) forming processes.
In Figure 1 is shown a UOE method for production of longitudinally welded large diameter tubes. Longitudinally edges of steel plates are first beveled using carbide milling equipment. Beveled plates are then formed into a U shape using a U-press subsequently into an O shape using an O-press.
Figure 1: Longitudinal seam Submerged Welded (LSAW) tubes with UOE process
Inspection: Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation), Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test), Exterior Size Inspection, Hydrostatic Test, X-ray Test. Application of LSAW Steel Tubes : The tubes are mainly used for oil, natural gas, gas, central heating, water supply, sewage treatment, low-pressure fluid delivery and so on.