Difference between LSAW and HSAW Pipes

Difference between LSAW and HSAW Pipes

LSAW and HSAW Pipes are widely used in Oil and Gas sector cross country pipeline. A careful option study is required for selection of Pipe type to complete project on schedule and to complete the project with lesser cost and better Internal rate of return (IRR).

LSAW :- Longitudinal Submerged Arc welded

As the name suggest, the LSAW pipe has longitudinal welding seam and the welding method is Submerged arc welding.

LSAW pipe is made of plain metal plate or sheet. First metal sheet goes to edge milling followed with bending as per required pipe diameter. The edge of the bend plate are finished with V shaped groove. The two open edge of sheet get welded internally as well as externally with a longitudinal welding seam with Submerged arc welding process. LSAW pipes are costly than HSAW pipe as the metal sheet cost is more than coil cost. 

Check home page for coil and metal sheet cost under commodities section.

Larger the required diameter of Pipe,  larger width of sheet would be required in case of LSAW Pipe.  

However there is limitation on width and length of Metal plate manufacturing, Hence only smaller diameter pipe can be manufactured as LSAW Pipe. LSAW pipes are recommendable from 16 inch to 60 inch diameter of pipe. It must be noted that lesser diameter pipes (Less than 16 inch ) are made of ERW rather than SAW.

LSAW Pipe with its longitudinal weld having good strength.

Final product either LSAW or HSAW pipe , go with various quality assurance check like Radiography testing , Ultrasonic testing, Hydro testing as well as physical examination of external appearance examination.

HSAW :-Helical  Submerged Arc welded

As the name suggest, the HSAW pipe has helical welding seam and welding method is Submerged arc welding.

HSAW pipe is made of helical metal coil.  Helical coil are metal sheet with less width but it is of good length and wrapped in form of coil.

There are so many benefits of using helical coil for manufacturing of Pipe.

Helical coil are cheaper than metal plate. Hence the cost of HSAW pipe manufacturing is less than LSAW Pipe. It can be used for Higher diameter of HSAW Pipe manufacturing as there is no limitation on diameter of pipe.

The two open edge of sheet get welded with a helical welding seam with Submerged arc welding process. The weld seam has higher length than actual pipe length. This is reason that HSAW Pipe with helical weld having lesser strength than LSAW Pipe. 

The long helical welding makes pipes prone to crack defects ,uneven weld accumulation etc.

 

A typical type of pipe manufactured is listed below. 

Type of Pipe HSAW LSAW ERW
Diameter in Inch 18 to 140 16 to 60 1.5 to 20
Thickness in mm 6 to 25 16 to 60 4 to 14
Service Onshore Oil & Gas Pipeline  Onshore Oil & Gas Pipeline  Onshore Oil & Gas Pipeline
  Water Transmission Pipeline Offshore Oil & Gas Pipeline  

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