Introduction
When a pipeline requires a large diameter, heavy wall, or demanding weld quality, the welding method becomes an important factor in pipe selection. DSAW steel pipe is widely used for large-diameter welded pipe because its longitudinal or helical seam is welded from both sides using submerged arc welding.
However, DSAW is a welding method rather than a separate pipe type or product standard. Buyers also need to understand how it relates to LSAW, which standards apply, and what inspection requirements should be considered.
This guide explains how DSAW works, where it is used, and what buyers should check before placing an order.
What Is DSAW?
What Does DSAW Stand For?
DSAW stands for Double Submerged Arc Welding. It refers to a welding process in which submerged arc welding is performed on both sides of a pipe seam.
During submerged arc welding, the arc is covered by granular flux. This protects the weld pool from the surrounding atmosphere. Welding wire is then fed into the joint to form the weld.
In DSAW production, the seam is welded from both the inside and outside of the pipe. The two welds are designed to achieve the required penetration and fusion through the pipe wall.
Therefore, DSAW should be understood as a welding process, not as a separate product standard.
How Is DSAW Related to LSAW and SSAW?
LSAW, SSAW, and DSAW describe different aspects of welded pipe production. LSAW and SSAW describe the seam configuration, while DSAW describes the welding method.
With LSAW steel pipe, the seam runs along the length of the pipe. The pipe is formed from steel plate before the longitudinal seam is welded. When submerged arc welding is used on both sides, the pipe can be described as both LSAW and DSAW.
The same principle applies to SSAW steel pipe. Its seam follows a spiral path around the pipe. If the seam is welded from both sides, it can also be classified as DSAW.
ASTM A1005/A1005M covers both longitudinal and helical seam steel pipe produced by double submerged arc welding.
| Term | What It Describes | Seam / Welding Method |
| LSAW | Longitudinal welded pipe | Longitudinal seam |
| SSAW | Spiral welded pipe | Helical seam |
| DSAW | Double submerged arc welding | Welding from both sides |
A pipe can therefore be LSAW and DSAW when it has a longitudinal seam welded from both sides. It can also be SSAW and DSAW when its spiral seam is welded in the same way.
How Is DSAW Steel Pipe Manufactured?
DSAW steel pipe is made by forming steel plate into a pipe shape. The seam is then welded from both sides using submerged arc welding. The exact sequence can vary according to the qualified welding procedure.
Step 1: Form the Steel Plate
The steel plate is formed into the required pipe shape. Its edges are brought together to create the seam.
Before welding begins, the joint is prepared to achieve the required weld penetration.
Step 2: Inside Welding (IW)
The first weld is made from inside the pipe. The welding torch follows the joint and fills the root of the seam.
Step 3: Outside Welding (OW)
The second weld is made from the outside. Additional weld metal is deposited to complete the joint.
The two welds fuse within the pipe wall. When the qualified welding procedure is followed, full penetration through the wall can be achieved.
Step 4: Dimensional Control
After welding, mechanical expansion may be used to improve dimensional accuracy. This process can help bring the pipe closer to the required roundness.
DSAW vs. Single-Sided SAW: What Is the Difference?
| Comparison | Single-Sided SAW | DSAW |
| Welding method | Welding from one side | Welding from both sides |
| Weld configuration | Single-sided weld | Inside weld + outside weld |
| Penetration | Depends on joint design and welding procedure | Two-sided welding can support full-wall penetration |
| Typical use | Used when single-sided welding meets project requirements | Often used for large-diameter or heavy-wall pipe |
Where Is DSAW Steel Pipe Used?
DSAW steel pipe is mainly used when large-diameter welded pipe is required. Common applications include:
Oil and Gas Pipelines
DSAW pipe is widely used for oil and gas transmission pipelines. API 5L line pipe is commonly specified for these projects.
Water Transmission
Large-diameter DSAW pipe is also used in municipal and industrial water transmission systems. It is suitable for projects that require large pipe diameters and defined wall thicknesses.
Piling and Structural Projects
DSAW pipe can be used for steel piling and large structural projects. Its large diameter makes it suitable for applications where high load capacity is required. It can also be supplied as a large diameter steel pipe for specific foundation and infrastructure projects.
Offshore and Infrastructure Projects
DSAW pipe may also be used in offshore pipelines, marine structures, and major infrastructure projects. The required grade, dimensions, coating, and inspection level depend on the project specification.
How to Choose DSAW Steel Pipe for Your Project?
There is no universal wall thickness or pressure limit that requires DSAW. The welding method should be selected according to the pipe design and project requirements.
Consider Wall Thickness
DSAW is often considered for heavy-wall pipe because welding from both sides can help achieve the required penetration.
For thinner pipe, single-sided SAW may be suitable when the qualified welding procedure meets the applicable requirements. A fixed limit, such as 10–14 mm, should not be treated as a universal rule.
Check Pipe Grade and PSL
The pipe grade also affects welding and testing requirements.
For API 5L PSL 2 line pipe, stricter requirements may apply to weld quality and testing. DSAW can be preferred when tighter control of the welded joint is required.
For PSL 1 pipe, single-sided SAW may be acceptable when it meets the applicable requirements. The project specification should always be checked before the welding method is selected.
Consider Service Conditions
Low-temperature service requires adequate impact toughness. High-pressure applications also place greater demands on the pipe and welded joint.
DSAW can be suitable for demanding service conditions. However, the welding method alone does not determine pressure capacity or low-temperature performance. The material grade and required tests must also be considered.
When high strength is required, a suitable high strength steel pipe grade should be selected according to the design conditions and applicable standard.
Follow the Applicable Standard
The final selection should be based on the required product standard.
For oil and gas pipelines, API 5L and ISO 3183 are common references. Both standards cover welded line pipe. The required PSL level depends on the project.
Before placing an order, buyers should confirm the pipe diameter, wall thickness, steel grade, PSL level, service conditions, applicable standards, and inspection requirements. The welding method can then be selected accordingly.
Cangtie DSAW Steel Pipe: Process, Quality, and Specifications
Cangtie supplies DSAW steel pipe for oil, gas, and heavy infrastructure projects. The pipes are formed from steel plate and welded from both sides using submerged arc welding.
Mature Production Technology
Cangtie follows established production procedures to maintain consistent weld quality. The DSAW process includes separate inside and outside welding stages. Full-wall penetration is required, with proper fusion between the weld passes.
Welding parameters are controlled according to the qualified procedure. For carbon steel with a wall thickness of 12–25 mm, the typical heat input is 1.8–2.5 kJ/mm. Weld alignment is also controlled during production. For applicable API 5L products, misalignment is kept within the limits specified by the relevant standard and project requirements.
Quality Control and Inspection
Quality is checked throughout production. Welding parameters are monitored according to the qualified procedure.
Depending on the standard and project requirements, inspection may include automatic ultrasonic testing, radiographic testing, magnetic particle testing, hydrostatic testing, and mechanical testing.
For API 5L products, the requirements cover manufacturing, inspection, testing, marking, and traceability. The current 47th edition of API Spec 5L was published in June 2026.
Technical Specifications and Material Grades
Cangtie’s DSAW steel pipe is available in different sizes and grades for various project requirements.
| Parameter | Specification |
| Welding process | Double Submerged Arc Welding |
| Standards | API 5L PSL1/PSL2, ASTM A671, ASTM A672, EN 10219 |
| Material grades | Gr.B, X42, X52, X60, X65, X70, X80, S355JR |
| Outside diameter | 406–1422 mm |
| Wall thickness | 8–60 mm |
| Length | 6–12.5 m |
| Surface treatment | Bare, black varnish, 3PE, FBE, anti-corrosion oil |
For pipeline projects, the grade, PSL level, dimensions, coating, and inspection scope can be specified according to project requirements.
FAQ
What is DSAW steel pipe?
DSAW stands for Double Submerged Arc Welding. It refers to pipe whose seam is welded by submerged arc welding from both the inside and outside.
What are the advantages of DSAW pipe?
DSAW can provide good weld penetration and joint quality, especially for large-diameter or heavy-wall pipe. Final performance depends on the material, welding procedure, and applicable standard.
What sizes of DSAW steel pipe are available?
Cangtie supplies DSAW steel pipe with outside diameters from 406 to 1422 mm and wall thicknesses from 8 to 60 mm. Lengths from 6 to 12.5 m are available.
Conclusion
DSAW steel pipe is a practical option for projects that require large diameters, heavy wall thicknesses, and controlled weld quality. The process uses submerged arc welding on both sides of the pipe seam.
For buyers, it is important to distinguish DSAW from LSAW. DSAW describes the welding process, while LSAW describes the longitudinal seam configuration. Many LSAW pipes are manufactured using DSAW.
The right pipe should be selected according to the project specification. Key factors include pipe size, wall thickness, steel grade, service conditions, applicable standards, and inspection requirements.
Looking for DSAW steel pipe for your next project? Contact Cangtie to discuss your required specifications, standards, and inspection requirements.
