1. What "DN2391" Actually Means
DN: Stands for "Diameter Nominal." It is a dimensionless number representing the approximate internal diameter in millimeters. It is the European equivalent of the North American "NPS" (Nominal Pipe Size).
2391: This indicates a nominal diameter of 2391 mm, which is approximately 94.13 inches.
So, a DN2391 pipe has an internal diameter of roughly 2.39 meters (7.8 feet).
2. Corresponding North American Standard (NPS)
The closest NPS designation for DN2391 is NPS 94. Pipes of this size are not common and are considered specialized, custom-made products.
3. Common Carbon Steel Material Grades for Large Diameter Pipes
While "DN2391" defines the size, the pipe would be manufactured from a specific carbon steel material standard. The most common ones for large-diameter pipes are:
API 5L: This is the American Petroleum Institute standard for line pipe, used extensively in the oil and gas industry for transmission pipelines. Common grades include:
API 5L Grade B: A standard, low-cost grade for low to medium pressure.
API 5L X42, X52, X60, X65, X70, etc.: Higher strength grades (the number indicates the minimum yield strength in ksi). For a pipe this large, a high-strength grade like X65 or X70 is often used to withstand high internal pressures with thinner walls, saving on material and weight.
ASTM A106 / A53: These are standard specifications for seamless and welded carbon steel pipe for high-temperature service (A106) and general service (A53). They are common in process plants and power generation.
Grade A: Lower strength.
Grade B: The most common grade.
Grade C: Higher strength.
ASTM A252: This standard is specifically for welded steel pipe piles used in foundational construction (e.g., for bridges, buildings). This is a very likely application for a pipe of this diameter.
Grade 1, Grade 2, Grade 3: With increasing tensile and yield strength.
4. Manufacturing Process for DN2391 Pipe
A pipe of this massive size is always welded. It cannot be made seamless. The primary manufacturing processes are:
SAW (Submerged Arc Welding): This is the most common method.
U&O / UOE (U-ing and O-ing & Expanding): Steel plate is first pressed into a "U" shape, then into an "O" shape, and the longitudinal seam is welded on the inside and outside using SAW. The pipe is then mechanically expanded to achieve perfect roundness and relieve stresses.
JCOE (J-ing, C-ing and O-ing & Expanding): A similar process involving a step-by-step forming of the plate into a "J" shape, then a "C" shape, and finally an "O" shape before welding and expanding. This method is often more flexible for varying diameters and wall thicknesses.
5. Typical Dimensions (OD and Wall Thickness)
For DN2391, the Outside Diameter (OD) is fixed, while the wall thickness varies based on the pressure rating (schedule) or specific design requirements.
Outside Diameter (OD): According to the ISO 11960 standard, the OD for a DN2400 pipe (the closest standard size) is typically 2440 mm.
Wall Thickness: This can vary widely. For example:
Light Wall (e.g., for structural piles): Could be 12-16 mm.
Heavy Wall (e.g., for high-pressure pipeline): Could be 25 mm, 40 mm, or even thicker.
The exact dimensions (OD, WT, length) would be specified in the purchase order based on the project's engineering calculations.
6. Primary Applications
A carbon steel pipe of this enormous size is used in critical large-scale infrastructure:
Water Transmission Mains: For major cities or irrigation projects.
Oil and Gas Transmission Pipelines: As mainline pipes for long-distance transport.
Piling: As permanent structural foundations for bridges, skyscrapers, and offshore platforms (using ASTM A252).
Penstocks: Large pipes that carry water to hydroelectric turbines.
Stormwater and Sewage Outfalls: Large-diameter discharge pipes.
Summary
| Feature | Description |
|---|---|
| Full Designation | Typically something like: API 5L X65 PSL2 DN2391 |
| Meaning of DN2391 | Nominal Diameter of 2391 mm |
| Equivalent NPS | NPS 94 |
| Approx. Outside Diameter | ~2440 mm (96 inches) |
| Material | Carbon Steel (per API 5L, ASTM A106, ASTM A252, etc.) |
| Manufacturing | Welded (SAW, UOE/JCOE process) |
| Key Applications | Major pipelines, water mains, structural piling, penstocks |
In conclusion, "DN2391 Carbon Steel Pipe" refers to a massive, custom-welded pipe specified by its European size code. The exact material grade, wall thickness, and length are determined by the specific pressure, structural, and environmental demands of the project it will be used for. When sourcing such a pipe, you would need to provide the full material specification and required dimensions to a manufacturer capable of large-diameter pipe production.
