Summary
A DIN 17100 LSAW steel pipe refers to a Longitudinally Submerged Arc Welded pipe manufactured from steel that conforms to the German industrial standard DIN 17100. This standard, now largely superseded but still widely referenced, specifies the technical delivery conditions for non-alloy quality steels.
The key points are:
LSAW: The manufacturing process creates a high-strength, large-diameter pipe.
DIN 17100: The material standard defines the chemical and mechanical properties of the steel used.
1. What is LSAW Pipe?
LSAW is a manufacturing process for creating large-diameter steel pipes (typically from 16 inches up to 60 inches or more).
Process: Steel plates (skelp) are first formed into a U-shape and then an O-shape in a press or roller. The longitudinal seam is then welded on the inside and outside using the Submerged Arc Welding (SAW) process. SAW involves forming an arc between a continuously fed electrode and the workpiece, with a layer of fusible granular flux covering the arc. This produces high-quality, robust welds with deep penetration.
Key Characteristics:
High Strength: Suitable for high-pressure applications.
Large Sizes: Can produce pipes with larger diameters and thicker walls than other methods like ERW (Electric Resistance Welding).
Reliable Welds: The SAW process is automated and provides excellent weld integrity.
2. Understanding DIN 17100
DIN 17100 is the historic German standard for "Non-alloy quality steels (Qualitätsstähle)". Its full title is "DIN 17100: Steel for general structural purposes; Quality standards".
Purpose: It defines grades of carbon and carbon-manganese steels based on their minimum yield strength (ReH) and impact energy properties. The most common grades under this standard are St 37, St 44, St 52, and their sub-grades.
Current Status: DIN 17100 has been officially replaced by the European standard EN 10025-1/2 (Non-alloy structural steels). However, the old designations are still very commonly used in specifications and industry parlance, especially for projects with German engineering influence.
Common Steel Grades under DIN 17100 and their EN 10025 Equivalents:
| DIN 17100 Grade | Approximate EN 10025 Grade | Minimum Yield Strength (ReH) | Key Characteristics |
|---|---|---|---|
| St 37 | S235 | 235 MPa | Good weldability and formability, general structural use. |
| St 44 | S275 | 275 MPa | Medium strength, general structural use. |
| St 52 | S355 | 355 MPa | Higher strength, used for more demanding structural and pressure applications. |
*Note: The sub-grades (e.g., St 37-2, St 52-3) indicate different impact toughness requirements at specific temperatures.*
3. Combining the Two: DIN 17100 LSAW Pipe
A pipe specified as "DIN 17100 LSAW" means:
The pipe is manufactured using the LSAW process.
The steel material used for the pipe plate conforms to the chemical composition and mechanical properties (yield strength, tensile strength, elongation, impact toughness) defined by a specific grade within the DIN 17100 standard (e.g., St 37, St 52).
4. Key Specifications for DIN 17100 LSAW Pipes
When ordering or specifying such a pipe, the full description would include:
Material Grade: e.g., DIN 17100 St 52-3N
Manufacturing Standard: Often a pipe-specific standard like DIN 2458 (Longitudinally welded steel tubes) or API 5L for line pipe, which would reference the material properties.
Dimensions: Outside Diameter (OD) and Wall Thickness (WT).
Length: Random or fixed length.
Testing: Required tests (e.g., hydrostatic testing, non-destructive testing of welds, mechanical testing of samples).
5. Common Applications
Due to their strength and ability to be produced in large sizes, these pipes are used in critical heavy-duty applications:
Oil and Gas Transmission Pipelines: For onshore and offshore trunk lines.
Piling: As foundation piles for large structures and bridges.
Marine Structures: For constructing ports, off-shore platforms, and sea walls.
Civil Engineering: As structural columns in buildings and industrial halls.
Water Transmission: For large-diameter water mains.
Conclusion
In essence, DIN 17100 LSAW steel pipe is a robust, large-diameter pipe made from a defined quality of non-alloy steel. While the material standard (DIN 17100) is historic, it specifies well-understood and reliable steel grades. The LSAW manufacturing process ensures the pipe is capable of handling high stresses, making it a premier choice for major infrastructure projects worldwide. When encountering this specification, it's always good practice to confirm the exact material grade (e.g., St 52-3) and the applicable dimensional and testing standards.
