Welded vs Seamless Steel Pipe

Steel pipes ranges in seamless steel pipe and welded steel pipe, seamless pipe usually manufactured in hot rolled and cold drawn, welded pipe divided into: Straight seam welded pipe and spiral seam welded pipe. 

Ranges on production methods

Seamless and welded.

Seamless Steel Pipe

Seamless steel pipe as it's name, is manufacturerd from steel round billets, bars, use hot perforation process to transform the round bars in to round pipes. Although it includes several manufacturing processes as follows, hot rolled process used for diameters above 3'' to 24'', cold drawn processes use to produce small diameters below 2'', and cold drawn or cold rolled provides better tolerances than hot rolled. Extruded or jacking process as compensate way to produce pipes in special diameters or big diameters.

1. Hot rolled seamless, 
2. Cold rolled seamless,
3. Cold drawn seamless
4. Extruded pipes
5. Pipe jacking

​Welded Steel Pipe

Welded steel pipe manufactured from steel plates or coils, it use mechanical ways to transform the plates into pipe shapes and do the welding. Welded pipe has better production efficiency, lower cost, big diameters up to 100'' advantages than seamless pipes. There are DSAW, LSAW, SSAW, ERW, HFW different welding methods.

1. Double Submerged Arc Welding Pipe - SAW/DSAW, Ranges in LSAW pipe longitudinal submerged arc welding and SSAW spiral submerged arc welding. LSAW pipe also called JCOE pipe, which it made from steel plate by mechanical press the plates into J-shape, C-shape, O-shape and welding and cold expanding (OD range DN400 to DN1500 for JCOE process). SSAW pipe is made from steel strip or coils which not limited by plates width but can produce large diameters than LSAW pipe, OD range exceed DN2000.
2. Electric Resistance Welded Pipe - ERW (High Frequency HFW pipe, Low Frequency)
3. Gas welded Pipe
4. Furnace Welded Pipe

On seam Types

1. Straight seam, longitudinal seam
2. Spiral seam, spiral welded

Secion shapes

1. Round
2. Square
3. Oval
4. Triangular
5. Hexagonal
6. Rhombus
7. Octagonal
8. Semicircular 
9. Other Complex section Steel Pipe

Classified by Applications:

1. Heat exchanger
2. Machinery parts
3. Oil and gas, petroleum transmission
4. Drilling activities, drill pipe, casing and tubing
5. Chemical industry
6. Food, sugar industry
7. Power station