Stainless Steel Welded Pipes Supplier & Exporter
Metinox Overseas is a leading stainless steel welded pipe manufacturer in India that provides the complete line of SS welded pipes made using TIG, ERW and EFW method. We manufacture our stainless steel welded pipes in grades 304 and 304L, 316, 316L, 321, 347, and duplex 2205 NPS 1/8 to 72 schedules SCH 5S to SCH 80S. Being a reputable stainless steel welded pipe manufacturer in India, we provide fabricators, EPCs, and project buyers in 40+ countries and certify our mill tests with full third party inspection on all orders.
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Types of Stainless Steel Welded Pipes
Stainless Steel 304 Welded Pipes
Stainless Steel 304L Welded Pipes
Stainless Steel 304H Welded Pipes
Stainless Steel 310S Welded Pipes
Stainless Steel 310H Welded Pipes
Stainless Steel 316/316L Welded Pipes
Stainless Steel 316H Welded Pipes
Stainless Steel 316Ti Welded Pipes
Stainless Steel 317/317L Welded Pipes
Stainless Steel 321/321H Welded Pipes
Stainless Steel 347/347H Welded Pipes
We manufacture and supply all major types of SS welded pipes, each suited to specific pressure ratings, diameter requirements, and industry applications. All types are available in multiple grades and schedules with full ASTM / ASME / EN certification.
ERW (Electric Resistance Welded) Stainless Steel Pipes
ERW stainless steel welded pipes are produced by continuously forming a stainless steel strip or coil into a cylindrical shape and joining the longitudinal seam using electric resistance welding without the addition of filler metal. The weld zone is then heat-treated and the pipe solution-annealed and pickled. ERW produces a consistent, clean weld seam ideal for light-to-moderate pressure and general-purpose applications.
EFW (Electric Fusion Welded) Stainless Steel Pipes - ASTM A358
EFW stainless steel welded pipes are manufactured by rolling stainless steel plate into a cylindrical shape and joining the longitudinal seam by electric fusion welding using filler metal. The use of filler metal and full radiographic inspection makes EFW pipes suitable for large-diameter, heavy-wall, and high-temperature pressure service where ERW construction is not adequate.
Stainless Steel Welded Tubes - ASTM A249 / A269
Stainless steel welded tubes are manufactured from precision-rolled stainless strip, TIG-welded without filler metal, and drawn or sized to exact OD and wall tolerance. They are supplied per ASTM A249 for boiler, superheater, and heat-exchanger service, and ASTM A269 for general corrosive service where exact OD and wall dimensions are required rather than NPS scheduling.
Heavily Cold-Worked (HCW) Welded Pipes - ASTM A312
HCW pipes are produced by applying cold working of not less than 35% reduction in wall thickness to a welded pipe prior to final solution annealing. This process eliminates the weld seam distinction, giving HCW pipe mechanical properties closely equivalent to seamless, at improved dimensional precision. Suitable for high-pressure moderate-temperature service.
Large-Diameter Welded Pipes (EFW / LSAW)
For large-bore applications above NPS 14", Metinox supplies longitudinal submerged arc welded (LSAW) and EFW stainless steel pipes formed from heavy plate. Single or double longitudinal seam construction is available per purchaser approval. These large-diameter welded pipes are commonly used in desalination headers, offshore manifolds, and large industrial process lines.
Stainless Steel Structural Welded Pipes - ASTM A554
Stainless steel structural welded pipes per ASTM A554 are produced for mechanical and structural applications, not pressure service. Available in round, square, and rectangular profiles, they are the standard specification for architectural facades, balustrades, handrails, and structural frameworks requiring a consistent surface finish.
Available Grades for Stainless Steel Welded Pipes
Metinox stocks and supplies stainless steel welded pipes in a wide range of austenitic, duplex, and super duplex grades. Below is the full chemical composition and application reference.
Chemical Composition of SS Welded Pipe Grades
| Grade | UNS No. | C % Max | Cr % | Ni % | Mo % | Other | Key Property |
|---|---|---|---|---|---|---|---|
| TP304 | S30400 | 0.08 | 18.0-20.0 | 8.0-11.0 | - | - | General corrosion resistance; most widely used |
| TP304L | S30403 | 0.035 | 18.0-20.0 | 8.0-13.0 | - | - | Low-carbon; weld sensitisation-free |
| TP316 | S31600 | 0.08 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | - | Mo addition; pitting and crevice resistance |
| TP316L | S31603 | 0.035 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | - | Low-carbon 316; standard for welded pharma and marine |
| TP317L | S31703 | 0.035 | 18.0-20.0 | 11.0-15.0 | 3.0-4.0 | - | Higher Mo; enhanced acid resistance |
| TP321 | S32100 | 0.08 | 17.0-19.0 | 9.0-12.0 | - | Ti >= 5xC | Ti-stabilised; intergranular corrosion resistant |
| TP347 | S34700 | 0.08 | 17.0-19.0 | 9.0-13.0 | - | Nb+Ta >= 10xC | Nb-stabilised; oxidation resistant to 870C |
| TP310S | S31008 | 0.08 | 24.0-26.0 | 19.0-22.0 | - | - | High-temp service to 1100C |
| Duplex 2205 | S32205 | 0.030 | 21.0-23.0 | 4.5-6.5 | 2.5-3.5 | N 0.08-0.20 | 2x yield strength; SCC resistant |
| Super Duplex 2507 | S32750 | 0.030 | 24.0-26.0 | 6.0-8.0 | 3.0-5.0 | N 0.24-0.32 | PREN > 40; extreme seawater resistance |
| 904L | N08904 | 0.020 | 19.0-23.0 | 23.0-28.0 | 4.0-5.0 | Cu 1.0-2.0 | Super-austenitic; H2SO4 and HCl resistant |
Mechanical Properties Table - SS Welded Pipe Grades
| Grade | Tensile Strength Min (MPa) | Yield Strength Min (MPa) | Elongation Min % | Hardness Max (HRB) |
|---|---|---|---|---|
| TP304 / TP304L | 515 | 205 | 35 | 92 |
| TP316 / TP316L | 515 | 205 | 35 | 92 |
| TP317L | 515 | 205 | 35 | 95 |
| TP321 | 515 | 205 | 35 | 92 |
| TP347 | 515 | 205 | 35 | 92 |
| TP310S | 515 | 205 | 35 | 95 |
| Duplex 2205 | 620 | 450 | 25 | 31 HRC |
| Super Duplex 2507 | 795 | 550 | 15 | 32 HRC |
Internal links: SS 304 Welded Pipes | SS 316 Welded Pipes | SS 321 Welded Pipes | Duplex 2205 Welded Pipes | SS Welded Tubes | 304 vs 316 Comparison
Sizes, Schedules & Standards of Stainless Steel Welded Pipes
All Metinox stainless steel welded pipes conform to ASTM A312 / ASME SA312 (ERW/HCW), ASTM A358 / ASME SA358 (EFW), ASTM A554 (structural), and EN 10217-7 dimensional requirements. Mill test certificates to EN 10204 3.1 are standard; 3.2 third-party witnessed available on request.
| Standard | Full Title | Pipe Type | Key Grades |
|---|---|---|---|
| ASTM A312 / ASME SA312 | Seamless, Welded & Heavily Cold-Worked Austenitic SS Pipes | ERW / HCW | TP304, TP304L, TP316, TP316L, TP321, TP347, TP310S |
| ASTM A358 / ASME SA358 | Electric-Fusion-Welded Austenitic Cr-Ni SS Pipe - High-Temp & General | EFW | TP304, TP316, TP316L, TP317L, TP321, TP347, TP310S, 904L |
| ASTM A249 / ASME SA249 | Welded Austenitic SS Boiler, Superheater & HE Tubes | Welded Tubes | TP304, TP316, TP321, TP347 |
| ASTM A269 / ASME SA269 | Seamless & Welded Austenitic SS Tubing - General Service | Welded Tubes | 304, 316, 321 |
| ASTM A554 | Welded SS Mechanical Tubing | Structural Welded | 304, 316, 409, 430 |
| ASTM A790 / ASME SA790 | Seamless & Welded Duplex SS Pipes | Welded Duplex | S31803, S32205, S32750 |
| EN 10217-7 | Welded Steel Tubes for Pressure Purposes - SS | Welded | 1.4301 (304), 1.4404 (316L), 1.4571 (316Ti) |
| JIS G3459 | SS Pipes | Welded | SUS304, SUS316, SUS321 |
| DIN 17457 | Welded Circular Tubes of Austenitic SS | Welded | 1.4301, 1.4401 |
Size & Schedule Reference Table
| Product Type | NPS / OD Range | Wall Thickness / Schedule | Standard Length |
|---|---|---|---|
| ERW Welded Pipe (small bore) | 1/8" - 12" NPS | SCH 5S, 10S, 40S, 80S | 6 m / SRL / CTL |
| ERW Welded Pipe (medium bore) | 14" - 24" NPS | SCH 5S, 10S, 20, 40 | 6 m / Custom |
| EFW Pipe (ASTM A358) | 8" - 72" NPS | 3 mm - 60 mm wall | 6 m / Custom |
| HCW Pipe (ASTM A312) | 1/8" - 14" NPS | SCH 5S - SCH 80S | 6 m / SRL / CTL |
| Structural Welded Tube (A554) | 1/8" - 24" NPS | 0.5 mm - 6 mm wall | 6 m / Custom |
| Welded Tube (A249 / A269) | 6 mm - 508 mm OD | 0.5 mm - 12 mm wall | 6 m / Custom |
ASTM A312 Welded Pipe - Wall Thickness Table (Selected NPS, ANSI B36.19M)
| NPS (inch) | OD (mm) | SCH 5S (mm) | SCH 10S (mm) | SCH 40S (mm) | SCH 80S (mm) |
|---|---|---|---|---|---|
| 1/2" | 21.34 | 1.65 | 2.11 | 2.77 | 3.73 |
| 1" | 33.40 | 1.65 | 2.77 | 3.38 | 4.55 |
| 2" | 60.33 | 1.65 | 2.77 | 3.91 | 5.54 |
| 4" | 114.30 | 2.11 | 3.05 | 6.02 | 8.56 |
| 6" | 168.28 | 2.77 | 3.40 | 7.11 | 10.97 |
| 8" | 219.08 | 2.77 | 3.76 | 8.18 | 12.70 |
| 10" | 273.05 | 3.40 | 4.19 | 9.27 | 12.70 |
| 12" | 323.85 | 3.96 | 4.57 | 9.53 | 12.70 |
Full dimensional data per ANSI/ASME B36.19M. Custom wall thicknesses available on inquiry.
ASTM A358 EFW Pipe - Size & Class Reference
| Class | Weld Type | Filler Metal | Radiography | Typical Application |
|---|---|---|---|---|
| Class 1 | Double welded | All passes | 100% RT | Critical pressure service, boilers |
| Class 2 | Double welded | All passes | None required | General industrial, moderate pressure |
| Class 3 | Single welded | All passes | 100% RT | Process piping, chemical service |
| Class 4 | Single welded | Outer passes only | 100% RT | Large-bore general service |
| Class 5 | Double welded | All passes | Spot RT | Low-risk general applications |
Tolerance Table - ASTM A312 Welded Pipes
| Parameter | Tolerance |
|---|---|
| Outside Diameter (NPS <= 1 1/2") | +- 0.4 mm |
| Outside Diameter (NPS > 1 1/2") | +- 0.75% |
| Wall Thickness - under tolerance | -12.5% of nominal |
| Weld area - over tolerance | Not limited |
| Straightness | 1.5 mm per 1.5 m |
| Length (SRL: 4.8-7.3 m) | As agreed |
| Length (DRL: 8.5-14.6 m) | As agreed |
Applications of Stainless Steel Welded Pipes
Stainless steel welded pipes from Metinox Overseas are specified across a wide range of industries globally wherever cost-effective, corrosion-resistant piping is required in standard to large diameters.
Oil & Gas: ERW TP316L welded pipes are used in refinery utility lines, gas treatment facility headers, and offshore non-critical process circuits. Large-bore manifolds and injection headers are supplied in EFW duplex 2205.
Chemical & Petrochemical Processing: ASTM A358 EFW TP316L and 904L welded pipes are used in reactor headers, distillation feed lines, and large-bore acid process piping where seamless construction is less practical.
Pharmaceutical & Biotechnology: ASTM A312 TP316L ERW welded pipes with weld bead removal and electropolished bore are used for WFI loops, clean steam distribution, CIP/SIP systems, and bioprocess utility lines.
Power Generation: ASTM A358 TP321 and TP347 EFW pipes are used in large-bore steam headers, feedwater lines, and heat-exchanger inlet and outlet connections.
Shipbuilding: ERW and SD 2507 EFW pipes are used for seawater cooling mains, ballast water treatment systems, fire suppression mains, and cargo manifolds in ships and FPSO units.
Construction & Architecture: ASTM A554 TP304 and TP316 structural welded pipes in round, square, and rectangular profiles are used in facades, curtain walls, handrails, and balustrade structures.
HVAC Building Services: TP304 SCH 5S ERW welded pipes are used for chilled-water mains, heating loops, compressed-air distribution, and utility services requiring moderate corrosion resistance.
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FAQs About Stainless Steel Welded Pipes
ASTM A312 deals with welded pipes which are made through automatic welding devoid of filler metal (ERW/HCW) and it covers sizes NPS 1/8 to NPS 30. ASTM A358 is used when electric-fusion-welded (EFW) pipes made filled with optional radiographic inspection are used in services of large diameter (NPS 8 to 72) and heavy-wall high-temperature and high-pressure service. A312 is less expensive to standard sizes; A358 is used to critical service of large bore.
SS welded pipe (TP304L) is the standard option when using in food processing, pharmaceutical utilities, HVAC, and general industrial applications in which there is minimal exposure to chlorides. The SS 316 welded pipe (TP316L) contains 2-3% molybdenum which is much more resistant to pitting corrosion and crevice corrosion when used in chloride rich environments, usually required in marine, coastal and chemical process piping. When welding, we should always make the low-carbon L-grade (304L or 316L) when we do not want to experience sensitisation of the weld-zone.
Yes. Metinox Overseas is a well established manufacturer of stainless steel welded pipes in India with manufacturing of ERW, EFW and HCW stainless steel welded pipes in grades of 304, 316, 316L, 321, 347, duplex 2205 and super duplex 2507 to ASTM A312, ASTM A358 and EN 10217-7. We are also a manufacturer and not merely a stockist, we include direct-mill prices, complete heat traceability, and we have the ability to make non-standard sizes and wall thicknesses to customer drawings and project requirements.
EN 10217-7 European Welded pressure stainless steel tube is the standard of welded steel tubes. It includes the austenitic and duplex grades (1.4301/304, 1.4404/316L, 1.4571/316Ti and duplex 1.4462/2205) in welded tube form that is needed in projects in European countries that have applied PED ( Pressure Equipment Directive ). SS welded pipes and tubes are also supplied by Metinox to the European export projects as per EN 10217-7. Dual certification supply is supplied with equivalent grades coupled with ASTM A312 / A358.
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