Classification of welded steel pipes
Welded steel pipes can be classified into the following major categories based on their production process, weld seam type, and application field. Each type has its own unique process characteristics and applicable scenarios:
Classification by welding process
|
Type |
English abbreviation |
Process characteristics |
Typical applications |
|
High-frequency resistance welded pipe |
ERW |
High-frequency current is used to heat the edges of the tube blank, which is then extruded (without welding material). The weld seam is smooth and production efficiency is high. |
Building structures, water pipes, oil and gas pipelines |
|
Straight seam submerged arc welded pipe |
LSAW |
Steel plate milling → JCO/UOE forming → Double-sided submerged arc welding High weld quality, capable of producing large-diameter thick-walled pipes |
Oil/gas long-distance pipelines, offshore platforms |
|
Spiral submerged arc welded pipe |
SSAW |
Steel strip spiral curling forming → continuous submerged arc welding Flexible diameter adjustment |
Municipal pipe networks, pile pipes, low-pressure fluid conveyance,Automotive exhaust systems, precision mechanical components |
|
Laser welded tubes |
LASW |
High-energy laser beam welding Small heat-affected zone, suitable for thin-walled precision tubes |
Municipal pipe networks, pile pipes, low-pressure fluid conveyance,Automotive exhaust systems, precision mechanical components |
Classification by weld shape
|
Type |
Features |
Advantages |
|
Straight welded steel pipe |
Weld seam parallel to the axis of the pipe body(ERW/LSAW) |
High dimensional accuracy and good pressure resistance |
|
Spiral welded steel pipe |
Weld seam in a spiral line (SSAW) |
High bending resistance, suitable for dynamic load environments |
|
Seamless steel pipe |
Eliminate welds through cold rolling/hot expansion processes |
Appearance close to seamless tubes, more competitive pricing |
Classified by subsequent processing methods
|
Treatment method |
Technical points |
Effect |
|
Hot-dip galvanized welded pipe |
Zinc liquid immersion coating |
Corrosion resistance improved by 3-5 times (ASTM A53) |
|
Cold-galvanized welded pipe |
Cold-galvanized welded pipe |
Low cost, suitable for indoor dry environments |
|
Corrosion-resistant coated pipes |
3PE (epoxy + adhesive + polyethylene) or FBE (fused epoxy) |
Suitable for acidic soil/subsea pipelines (API 5L) |
|
Cold-rolled precision welded tubes |
Cold-rolled reduction in diameter after welding |
Seamless tubes as an alternative to machining |
Technical Selection Recommendations
a.Pressure priority: Choose LSAW or thick-walled ERW pipes.
b.Cost priority: SSAW is 15-20% cheaper than LSAW.
c.Corrosion protection requirements: 3PE coated pipes can have a service life of up to 50 years when used in soil.
d.Precision applications: LASW can replace some cold-drawn seamless tubes.
Understanding these classification standards can help engineers and purchasers select the optimal welded steel pipe solution based on specific operating conditions (pressure, medium, environment, etc.).
