API 5L welded steel pipe types on oil pipelines include spiral submerged arc welded pipe (SSAW), longitudinal submerged arc welded pipe (LSAW), and electric resistance welded pipe (ERW).

There are many grades of raw materials for API 5L steel pipes like: GR.B, X42, X46, X52, X56, X60, X70, X80, etc. ANSI / API 5L specifies the manufacture of two product levels (PSL1 and PSL2).

Pipeline pipes should be subjected to water pressure tests one by one, and the standard does not provide for non-destructive substitution of water pressure. This is also a big difference between API standards and Chinese standards. PSL1 does not require non-destructive inspection, PSL2 should be non-destructive inspection one by one.

Applied for petroleum and natural gas industries, oil industries requirements for transportation and are expected working in extreme situations, low and high temperatures, corrosion resistance for corrosive environments, and for sour services in H2S conditions.

There are 3 welding types: ERW (Electric Resistance Welding), LSAW (Longitudinally Submerged Arc Welding), and SSAW (Spirally Submerged Arc Welding) welding types.

HIC Tested API Hot Finished Seamless (HFS)
API 5L Cold Drawn or Finished Seamless (CDS)
PSL 2 API 5L Electric Resistance Welding (ERW)
API 5L PSL2 High-Frequency Induction Welding (HFIW)
Carbon Steel API 5L Hot Finished Welding (HFW)
API 5L Steel Butt Welded Pipes (BWP)
API 5L CS Electric Fusion Welding (EFW)
CS API 5L Sub-merged Arc Welding (SAW)
API Steel Cold Drawn Electric Resistance Welding (CEW)
API Spec 5L Oxy-Acetylene Welding (OAW)
API Hand-Welding or Manual Arc Welding (MAW)

LSAW pipe applied to diameters from 20 in (508 mm) to 40 in (1016 mm), there are many types of farming methods for LSAW steel pipes: UO (UOE), JCO (JCOE). The steel plate is first pressed into a U shape in the forming die, and then pressed into an O shape, and then internally and externally submerged arc welding is performed. After welding, it is usually called UOE welded pipe at the end of the full-length range (Expanding).

It is UO welded pipe. Roll Bending the steel plate, and then carry out internal and external submerged arc welding. After welding, the diameter is expanded to RBE welded pipe or not to RB welded pipe. The steel plate is formed in the order of J type-C type-O type, and the diameter is expanded to JCOE welded pipe after welding, or it is not expanded to JCO welded pipe.

LSAW Welded Steel Line Pipe (JCOE) Manufacturing Flow Chart:
Plate UT – Vacuum Lifting – Ultrasonic Inspection – Edge Milling – Pre Bending – Type J Forming – Type C Forming – Type O Forming – Tack Welding By CO2 Gas Shield Arc Welding – Tab Welding – Inside Welding – Outside Welding – Removal of Tab Plate – Cleaning – Rounding – X Test – Ultrasonic Testing – Washing Before Expansion – Mechanical Expansion – Washing After Expansion – Straightness – Hydrostatic Test – Ultrasonic Testing – Weld Grinding for Pipe Ends – Mechanical Facing – X-Ray Test for Body and Both Ends – Ultrasonic Testing for Pipe Ends – Magnetic Particle Inspection For Both Ends – Weighing and Measuring Length – Product Inspection – Outside Coating – Inside Coating – Marking – Packing and Warehousing

LSAW Welded Steel Line Pipe (UOE) Manufacturing Flow Chart:
The three main forming processes of the UOE LSAW steel pipe forming process include steel plate pre-bending, U forming, and O forming. Each process adopts a dedicated forming press to complete the three processes of pre-bending the edge of the steel plate, U forming and O forming in sequence to deform the steel plate into a circular tube.

SSAW pipe applied for diameters up to 60 in (1524 mm) made of strip steel coils as raw materials, often extruded and formed by automatic double-wire double-sided submerged arc welding. The spiral steel pipe feeds the strip steel into the welded pipe unit. After rolling by multiple rollers, the strip steel is gradually rolled up to form a round tube blank with an open gap. The reduction of the squeeze roller is adjusted to control the weld gap at 1~ 3mm and make both ends of the welding joint flush.

SSAW Steel Pipe Manufacturing Flow Chart:
Uncoiling – Flattening – Shearing and Butt Welding – Edge Milling – Preliminary Rolling – Forming – Inside and Outside Welding – Cutting Off – Ultrasonic Testing – X-Ray Test – Weld Grinding for Pipe Ends – Expanding at Pipe Ends – Hydrostatic Test – Ultrasonic Inspection – Pipe Ends Beveling – X Test – Production Inspection – Marking – Warehousing

As above manufacturing processes, we can see SAW (LSAW, SSAW) and ERW pipes are entirely different right from formation, welding, etc. and hence, the performance of both the pipes differ in the following aspects:

1. The Surface Quality.
The surface quality of ERW pipes is better when compared to SAW (LSAW, SSAW) pipes. As ERW pipes are smooth and have a better finish. Most of the SAW tube, it has weld reinforcement internal and external.

2. The Defects Found in ERW Pipes Are Lesser Than SAW Pipes.
As there is a solvent deposit in SAW. It results in more defects apart from the defects in the volume. The defects found in ERW pipes are only confined to wire-line and straight welds. And it can inspect. The defects can notice. And the ultrasonic reflection on the surface makes it easier to detect.

3. The Residual Stress Ratio in ERW is Lower Than SAW Pipes.
As ERW pipe deformation happens more in ERW followed by sizing of a flat oval. It results in elliptical vertical changes and necking, thereby making the stress smaller. The displacement of ERW pipes was smaller when compared to SAW pipes. Even they are using the same material. And it was also easy to detect.

4. The Performance.
Although the performance of both ERW and SAW pipes are the same. Once the pipes have a defect, the steel scrap and welding can do on ERW. While it is not the same in the case of SAW, which would result in cracking or corrosion, making the ERW more durable.

API 5L welded steel pipe is loose or in bundles tightened with Iron Strips. Special packings: Metal or Wooden Cases, Pallets, etc. Marking Requirements Rolled, die stamped, or paint stenciled (manufacturer’s option).

Manufacturer’s name, brand, or trademark
Hydrostatic test pressure and/or NDE, or NH if neither is specified
Size, length, weight per foot (NPS 4 and larger)
ANSI schedule number or weight class or wall thickness
Additional “S” if tested supplementary requirements

For Petroleum and natural gas industries, steel pipe for pipeline transportation systems.
Steel pipe Inc supplied the pipe complied with the international standard API 5L, which specified requirements for the manufacture of two product specifications levels (PSL1 and PSL2) of welded line pipe for use in pipeline transportation systems in the oil and gas industries.