The Large Diameter Stainless Steel Welded Pipe is manufactured by roll forming high-quality stainless steel plate or coil into a cylindrical shape and welding the longitudinal seam using advanced TIG, plasma, or submerged arc welding (SAW) technology. Designed for applications requiring high flow capacity, structural strength, and corrosion resistance, this pipe is available in diameters exceeding the limits of seamless manufacturing. It offers a cost-effective solution for large-scale fluid transport, structural supports, and industrial process systems where diameter requirements range from 14 inches to 48 inches and beyond.
Product Specifications
| Parameter | Details |
|---|
| Standards | ASTM A312, A358, A409; EN 10217-7; ASME B36.19 |
| Available Grades | 304, 304L, 316, 316L, 317L, 321, 347, 310S, Duplex 2205 |
| Outer Diameter | 14″ – 48″ (323.9 mm – 1219 mm); larger upon request |
| Wall Thickness | 3.0 mm – 12.7 mm (Schedule 5S, 10S, 40S; or custom) |
| Length | 3m, 6m, or custom lengths up to 12m |
| Welding Process | TIG (GTAW), Plasma, SAW (Submerged Arc Welding) |
| Weld Seam | Single longitudinal seam (straight seam) |
| Heat Treatment | Annealed after welding (standard) |
| Surface Finish | Pickled, passivated, or mill finish |
| End Finish | Plain ends, beveled ends (for field welding) |
Chemical Composition (Typical Values, %)
| Grade | C ≤ | Si ≤ | Mn ≤ | P ≤ | S ≤ | Cr | Ni | Mo |
|---|
| 304L | 0.03 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-12.0 | – |
| 316L | 0.03 | 0.75 | 2.00 | 0.045 | 0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 |
| 317L | 0.03 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 11.0-15.0 | 3.0-4.0 |
| Duplex 2205 | 0.03 | 1.00 | 2.00 | 0.030 | 0.020 | 22.0-23.0 | 4.5-6.5 | 3.0-3.5 |
Composition per ASTM A312 / A358.
Mechanical Properties (at Room Temperature)
| Grade | Tensile Strength (MPa) min | Yield Strength (MPa) min | Elongation (%) min | Hardness (HB) max |
|---|
| 304L | 485 | 170 | 35 | 201 |
| 316L | 485 | 170 | 35 | 217 |
| 317L | 515 | 205 | 35 | 217 |
| Duplex 2205 | 620 | 450 | 25 | 290 |
Tested in accordance with ASTM E8 / E8M.
Large Diameter vs. Standard Diameter
| Property | Large Diameter (14″-48″) | Standard Diameter (1/8″-12″) |
|---|
| Manufacturing | Plate-formed, welded | Coil-formed, welded or seamless |
| Wall thickness | 3.0 mm – 12.7 mm | 0.5 mm – 12.7 mm |
| Typical length | 6m | 6m |
| Welding process | TIG / Plasma / SAW | TIG / Laser / ERW |
| Primary applications | Bulk fluid, structural, utilities | Process piping, instrumentation |
Dimensional Tolerances (ASTM A312 / A358)
| Parameter | Tolerance |
|---|
| Outer diameter | ±0.8% (max ±6.4 mm) |
| Wall thickness | ±10% |
| Length (fixed) | +0 / -3 mm |
| Straightness | 0.2% of total length |
| Ovality | Within OD tolerance |
Schedule Wall Thickness – Large Diameter (ASME B36.19)
| NPS (inch) | OD (mm) | Schedule 5S (mm) | Schedule 10S (mm) | Schedule 40S (mm) |
|---|
| 14″ | 355.6 | 3.96 | 4.78 | 9.53 |
| 16″ | 406.4 | 4.19 | 4.78 | 9.53 |
| 18″ | 457.2 | 4.19 | 4.78 | 9.53 |
| 20″ | 508.0 | 4.78 | 5.54 | 9.53 |
| 24″ | 609.6 | 5.54 | 6.35 | 9.53 |
| 30″ | 762.0 | 6.35 | 7.92 | 9.53 |
| 36″ | 914.4 | 6.35 | 7.92 | 9.53 |
| 42″ | 1066.8 | 6.35 | 7.92 | 9.53 |
| 48″ | 1219.2 | 6.35 | 7.92 | 9.53 |
Welding Processes for Large Diameter Pipe
| Process | Description | Typical Use |
|---|
| TIG (GTAW) | Root pass for high-quality welds | Sanitary, high-purity |
| Plasma | Deep penetration, smooth bead | General industrial |
| SAW (Submerged Arc) | High deposition rate | Heavy wall, structural |
| Combination (TIG + SAW) | TIG root + SAW fill/cap | High-quality + efficient |
Weld Quality Assurance
| Inspection Method | Standard Practice |
|---|
| Hydrostatic Test | 100% of production |
| Radiographic Test (RT) | Upon request (typically 10-100%) |
| Ultrasonic Test (UT) | Upon request |
| Dye Penetrant Test (PT) | Upon request for weld surface |
| Visual Inspection | 100% of weld seam |
Large Diameter Welded vs. Seamless
| Property | Large Diameter Welded | Seamless (if available) |
|---|
| Max diameter | 48″+ | 24″ (610 mm) |
| Cost | Lower (not available seamless) | N/A – seamless not available |
| Availability | Stocked or short lead time | Not available above 24″ |
| Weld seam | Present – NDT verified | None |
| Wall consistency | Good | N/A |
Contact Us
For inquiries, technical datasheets, or custom sizes, please contact our sales team.
