What is LSAW steel pipes? It’s Features and Manufacturing Processes.
Longitudinal submerged arc welding (LSAW) is a special welding technique used in the production of pipelines with particularly high requirements for finished wall thickness due to high internal or external pressure.
Therefore, the main application areas of straight seam submerged arc welded pipelines(LSAW steel pipes) include oil, natural gas, gas, centralized heating, water supply, sewage treatment, and other similar uses.
Steel pipe is a long hollow pipe mainly used to transport products from one place to another. They are mainly produced by two different manufacturing methods, either welded pipes or seamless pipes. In these two manufacturing methods, coarse steel is first cast into a more easily machined initial form (slab, hot steel billet, or flat strip). Then, by stretching the hot steel billets/billets into seamless pipes or pressing the edges of flat steel strips together and sealing them with welds, they are made into pipes. When operating conditions require higher wall thickness due to high internal or external pressure, LSAW (longitudinal submerged arc welding) pipelines are usually the most economical solution. The diameter range of straight seam submerged arc welded pipes is larger than resistance welding (ERW), typically ranging from 16 inches (406 millimeters) to 60 inches (1500 millimeters). Good resistance to high pressure and low temperature corrosion. In the straight seam submerged arc welded pipe unit, the processing is carried out by cold forming thick carbon steel plates, which are the prefabricated materials that many steel pipes rely on for their performance.
The material of the straight seam submerged arc welded steel pipe is a medium thick plate, which is wound in a forming machine or forming machine and welded with double submerged arc welding expansion. Wide range of specifications, with good toughness, ductility, uniformity, compactness and other characteristics. The manufacturing process of straight seam submerged arc welding (LSAW) pipes is achieved through the JCOE and UOE (during the forming process, the steel plate is shaped like the letters “J”, “C”, “O” or “U”, and then expanded) forming process, which bends and welds wide and thick steel plates from flat hot-rolled coils onto the steel pipe. Figure 1 shows a UOE method for producing large-diameter straight seam welded pipes. Firstly, use a hard alloy milling equipment to chamfer the longitudinal edges of the steel plate. Then, use a U-shaped press to shape the inclined sheet into a U-shape, and then use an O-shaped press to shape it into an O-shape.
The main technical parameters of LSAW steel pipes are as follows:
Wall thickness: up to 6.4-23.8mm (0.252-0.94in) in X80 steel grade; up to 6.4-26.4mm (0.252-1.04in) in X70 steel grade. The wall thickness can be increased to different degrees when the material is reduced.
Product standards: ISO3183, API Spec 5L, GB9711, AS/NZS 1163:2016, etc.
The diameter of LSAW steel pipe can reach Φ406.4-Φ1422.4mm.
The longest length of the pipe can be up to 12.8m.
Main features of LSAW steel pipes:
(1) The steel pipe has one longitudinal weld, and both internal and external welds are welded by one submerged arc welding.
(2) After the overall mechanical expansion treatment, the internal stress of the steel pipe is small and uniformly distributed, which can effectively prevent stress corrosion cracking, with high dimensional accuracy, which is convenient for on-site welding construction.
(3)Adopting the process of pre-welding and then finishing welding, the welding process is stable and the weld quality is high.
(4)The weld seam is easy to realise non-destructive flaw detection during production and non-destructive flaw review in the field during use.
(5)Wide range of product specifications, can produce both small diameter, large wall thickness and large diameter, large wall thickness of steel pipe.
Related topic: The difference between ERW steel pipes and LSAW steel pipes.
LONGMA produce and export LSAW steel pipes since 2003. As one of China leading steel pipes manufacturers since 2003, certified by API 5L, ISO9001, ISO14001, FPC, LONGMA always supply high quality API 5L B LSAW steel pipes/API 5L X42 LSAW steel pipes/API 5L X70 LSAW steel pipes/AS 1163 LSAW steel pipes with full range pipe grades & pipe specifications. Contact by info@ilongma.com to get more information.
