Stainless Steel EFW Pipes Supplier & Exporter
Metinox Overseas is a leading stainless steel EFW pipe manufacturer in India, with its specialisation being large diameter electric fusion welded stainless steel pipes to the ASTM A358 / ASME SA 358 standards. The SS EFW pipes are manufactured through rolling austenitic stainless steel plate and welding the seam using electric fusion welding with filler metal it provides a strong, radiographically-inspected weld seam applicable to high-pressure and high-temperature corrosive service. Grades of 304, 304L, 316, 316L, 317L and 321 available in NPS 8 through 72 across Classes 1 to 5 with each pipe containing full mill test certification.
Request a quote now!Types of Stainless Steel EFW Pipes
Stainless Steel 304 EFW Pipes
Stainless Steel 304L EFW Pipes
Stainless Steel 304H EFW Pipes
Stainless Steel 310S EFW Pipes
Stainless Steel 310H EFW Pipes
Stainless Steel 316/316L EFW Pipes
Stainless Steel 316H EFW Pipes
 316Ti Welded Pipes.webp)
Stainless Steel 316Ti EFW Pipes
Stainless Steel 317/317L EFW Pipes
Stainless Steel 321/321H EFW Pipes
Stainless Steel 347/347H EFW Pipes
Stainless Steel 904L EFW Pipes
Types of Stainless Steel Electric Fusion Welded Pipes
Stainless steel EFW pipes under ASTM A358 are classified into five classes based on weld type, filler metal use, and radiographic inspection requirement. Selecting the correct class is critical to matching your pressure service and inspection code requirements.
1. ASTM A358 Class 1 EFW Pipe — Double Welded, 100% RT
ASTM A358 Class 1 is the highest-integrity SS EFW pipe classification. The pipe is double welded which is welded from both the outside and the inside — using filler metal in all passes. 100% radiographic (X-ray) inspection of the completed weld seam is mandatory per ASME Section V.
2. ASTM A358 Class 2 EFW Pipe — Double Welded, No RT Required
Class 2 stainless steel welded EFW pipes are double welded with filler metal in all passes, identical weld construction to Class 1 — but without the mandatory radiographic inspection requirement. Class 2 offers the structural benefit of double-sided welding at reduced inspection cost, suitable where the applicable piping code does not require full RT.
3. ASTM A358 Class 3 EFW Pipe — Single Welded, 100% RT
Class 3 electric fusion welded stainless steel pipes are single welded (from the outside only) with filler metal in all passes and 100% radiographic inspection of the weld seam. Single-side welding is used where internal access is limited or pipe diameter makes back-welding impractical.
4. ASTM A358 Class 4 EFW Pipe — Single Welded, Inner Pass Without Filler, 100% RT
Class 4 is identical to Class 3 except that the weld pass exposed to the inside pipe surface may be made without the addition of filler metal. This allows for autogenous (no-filler) root pass welding where this is preferred. 100% radiographic inspection is required.
5. ASTM A358 Class 5 EFW Pipe — Double Welded, Spot RT
Class 5 SS EFW pipes are double welded with filler metal in all passes, but require only spot (random) radiographic inspection per ASME Section VIII Div.1 UW-52, not full 100% RT. Class 5 balances construction quality with reduced inspection cost for lower-criticality large-bore applications.
6. Stainless Steel EFW Pipes — ASTM A671 / A672 (Carbon Steel Reference)
For projects specifying ASTM A671 CC65, ASTM A671 CC65 CL22, ASTM A672 C65 CL22, or A671 CC70 in carbon steel alongside stainless EFW pipes, Metinox can supply the full EFW pipe package across both carbon and stainless steel specifications. ASTM A671 / A672 are the carbon and alloy steel equivalents of ASTM A358 for EFW pipe, covering similar classes and weld quality requirements.
Available Grades for Stainless Steel EFW Pipes
Metinox manufactures stainless steel EFW pipes from austenitic stainless steel plate conforming to ASTM A240, covering all major grades from standard 304/316 through duplex and super-austenitic alloys.
CHEMICAL COMPOSITION OF ASTM A358 EFW 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 |
| TP304H | S30409 | 0.04–0.10 | 18.0–20.0 | 8.0–11.0 | — | — | High-carbon; elevated-temp creep strength |
| TP316 | S31600 | 0.08 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — | Mo addition; pitting & crevice resistance |
| TP316L | S31603 | 0.035 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — | Low-carbon 316; marine and pharma standard |
| TP316H | S31609 | 0.04–0.10 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — | High-carbon; creep-range pressure service |
| TP317L | S31703 | 0.035 | 18.0–20.0 | 11.0–15.0 | 3.0–4.0 | — | Higher Mo; acid process resistance |
| TP321 | S32100 | 0.08 | 17.0–19.0 | 9.0–12.0 | — | Ti ≥ 5×C | Ti-stabilised; high-temp sensitisation resistant |
| TP321H | S32109 | 0.04–0.10 | 17.0–19.0 | 9.0–12.0 | — | Ti ≥ 4×C | Creep-range elevated-temperature boiler service |
| TP347 | S34700 | 0.08 | 17.0–19.0 | 9.0–13.0 | — | Nb+Ta ≥ 10×C | Nb-stabilised; oxidation resistant to 870°C |
| TP347H | S34709 | 0.04–0.10 | 17.0–19.0 | 9.0–13.0 | — | Nb+Ta ≥ 8×C | High-temp boiler and superheater service |
| TP310S | S31008 | 0.08 | 24.0–26.0 | 19.0–22.0 | — | — | High-temp service to 1100°C |
| Duplex 2205 | S32205 | 0.030 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | N 0.08–0.20 | 2× 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 OF ASTM A358 EFW PIPE GRADES
| Grade | Tensile Strength Min (MPa) | Yield Strength Min (MPa) | Elongation Min % | Hardness Max (HRB) |
|---|---|---|---|---|
| TP304 / TP304L | 515 | 205 | 35 | 92 |
| TP304H | 515 | 205 | 35 | 92 |
| TP316 / TP316L | 515 | 205 | 35 | 92 |
| TP316H | 515 | 205 | 35 | 92 |
| TP317L | 515 | 205 | 35 | 95 |
| TP321 / TP321H | 515 | 205 | 35 | 92 |
| TP347 / TP347H | 515 | 205 | 35 | 92 |
| TP310S | 515 | 205 | 35 | 95 |
| Duplex 2205 | 620 | 450 | 25 | 31 HRC |
| Super Duplex 2507 | 795 | 550 | 15 | 32 HRC |
ASTM A358 EFW PIPES
| Base Metal Grade | Recommended Filler Metal (AWS) | Notes |
|---|---|---|
| TP304 / TP304L | ER308 / ER308L | Standard austenitic filler |
| TP316 / TP316L | ER316 / ER316L | Mo-bearing filler; matches base metal |
| TP317L | ER317L | Higher Mo content filler |
| TP321 | ER347 | Nb-stabilised filler preferred for 321 |
| TP347 / TP347H | ER347 | Nb-stabilised; matches base metal |
| TP310S | ER310 | High Cr-Ni filler for high-temp grades |
| Duplex 2205 | ER2209 | Over-alloyed duplex filler |
| Super Duplex 2507 | ER2594 | Over-alloyed super duplex filler |
Sizes, Schedules & Standards of Stainless Steel EFW Pipes
All Metinox stainless steel EFW pipes are manufactured to ASTM A358 / ASME SA358 and conform to ASME B36.19M dimensional requirements. Mill test certificates to EN 10204 3.1 are standard; 3.2 (third-party witnessed by SGS, BV, or TÜV) available on request.
STANDARDS AND SPECIFICATIONS
| Standard | Full Title | Application |
|---|---|---|
| ASTM A358 / ASME SA358 | Electric-Fusion-Welded Austenitic Cr-Ni SS Pipe for High-Temperature Service & General Applications | Primary standard for all SS EFW pipes |
| ASTM A240 / ASME SA240 | Chromium & Cr-Ni SS Plate, Sheet & Strip for Pressure Vessels & General Applications | Source plate material standard for A358 EFW manufacture |
| ASME B36.19M | Stainless Steel Pipe Dimensions | OD and wall thickness reference for schedule pipes |
| ASME B16.25 | Buttwelding Ends | Bevel end preparation for EFW pipe ends |
| ASME BPVC Section IX | Welding & Brazing Qualifications | WPS / PQR qualification for EFW weld processes |
| ASME BPVC Section V | Nondestructive Examination | Radiographic examination requirements (100% RT for CL1, CL3, CL4) |
| EN 10028-7 | Flat Products Made of SS for Pressure Purposes | European plate standard; used for EN-specified EFW |
| NACE MR0175 / ISO 15156 | Petroleum & Natural Gas — Materials for Sour Service | Required for duplex EFW pipes in H₂S service |
SIZE & WALL THICKNESS REFERENCE TABLE — ASTM A358 EFW PIPES
| NPS (inch) | OD (mm) | SCH 5S Wall (mm) | SCH 10S Wall (mm) | SCH 40S Wall (mm) | SCH 80S Wall (mm) | Custom Wall (mm) |
|---|---|---|---|---|---|---|
| 8" | 219.08 | 2.77 | 3.76 | 8.18 | 12.70 | Up to 60 mm |
| 10" | 273.05 | 3.40 | 4.19 | 9.27 | 12.70 | Up to 60 mm |
| 12" | 323.85 | 3.96 | 4.57 | 9.53 | 12.70 | Up to 60 mm |
| 14" | 355.60 | 3.96 | 6.35 | 9.53 | 12.70 | Up to 60 mm |
| 16" | 406.40 | 4.19 | 6.35 | 9.53 | 12.70 | Up to 60 mm |
| 18" | 457.20 | 4.19 | 6.35 | 9.53 | 12.70 | Up to 60 mm |
| 20" | 508.00 | 4.78 | 6.35 | 9.53 | 12.70 | Up to 60 mm |
| 24" | 609.60 | 6.35 | 6.35 | 9.53 | — | Up to 60 mm |
| 30" | 762.00 | — | 6.35 | — | — | Custom |
| 36" | 914.40 | — | 6.35 | — | — | Custom |
| 48" | 1,219.20 | — | — | — | — | Custom |
| 60" | 1,524.00 | — | — | — | — | Custom |
| 72" | 1,828.80 | — | — | — | — | Custom |
Full range: NPS 8" to NPS 72" (OD 219 mm to 1,829 mm) | Wall: 3 mm to 60 mm | Length: up to 6 m standard; custom lengths on request.
ASTM A358 CLASS COMPARISON TABLE
| Class | Weld Type | Filler Metal | Radiographic Inspection | Joint Efficiency | Best Application |
|---|---|---|---|---|---|
| Class 1 | Double welded | All passes | 100% RT (mandatory) | 1.00 | Critical pressure service, boilers, ASME BPVC |
| Class 2 | Double welded | All passes | None required | Per code (typ. 0.85) | General industrial, moderate pressure |
| Class 3 | Single welded | All passes | 100% RT (mandatory) | 1.00 | Large-bore where back welding is impractical |
| Class 4 | Single welded | Outer passes; inner autogenous | 100% RT (mandatory) | 1.00 | Autogenous root pass preferred; full RT |
| Class 5 | Double welded | All passes | Spot RT only | Per code | Non-critical large-bore, water service |
TESTING & INSPECTION REQUIREMENTS — ASTM A358
| Test | Requirement |
|---|---|
| Hydrostatic pressure test | Each pipe length — per ASTM A358 Clause 13 |
| Radiographic (X-ray) examination | 100% weld seam — CL1, CL3, CL4; Spot — CL5; None — CL2 |
| Transverse tension test | One specimen per lot per heat |
| Transverse guided-bend weld test | Face and root bend per heat |
| Visual and dimensional inspection | 100% all pipes |
| Chemical composition | Heat analysis + product analysis per A240 |
| Mechanical properties | Per applicable grade in A240 |
| Penetrant / magnetic particle examination | Optional — per supplementary requirement S3 |
| Ferrite content (weld deposit) | Optional — per supplementary requirement S4 |
| Intergranular corrosion test | Optional — per supplementary requirement S6 (ASTM A262 Practice E) |
STANDARD LENGTHS & END PREPARATION
| Parameter | Details |
|---|---|
| Standard length | Up to 6,000 mm (6 m) |
| Custom lengths | Available on inquiry |
| End preparation | Plain end (PE) / Bevelled end (BE) per ASME B16.25 (37.5° ± 2.5°) |
| Surface finish | No.1 pickled finish (standard) |
Applications of Stainless Steel EFW Pipes
Stainless steel EFW pipes per ASTM A358 are the industry standard for large-diameter, high-pressure, and high-temperature applications where seamless manufacture is impractical and weld integrity must be verified by radiographic inspection.
1. Oil & Gas
The products include Class 1 EFW TP316L and duplex 2205 large-bore pipes used in the crude distillation unit (CDU) outlet headers, gas treating plants manifolds, offshore production separators, and ties in spools.
2. Petrochemical & Chemical Processing
ASTM A358 Class 1 TP316L, TP317L and 904L EFW pipes are used in reactor inlet/outlet headers, reboiler circuits of distillation columns, acid process mains and the transfer of large bore chemical headers where seamless is not available in the necessary diameter.
3. Power Generation -- Boiler and Steam Headers
ASTM A358 / ASME SA358 Class 1 TP321H and TP347H EFW pipes used in the main steam line headers, superheater outlet headers, feed water heater connections, and main large heat exchanger steam lines.
4. Desalination & Water Treatment
Duplex 2205 and super duplex 2507 reverse osmosis (RO) pressure vessel header and brine recycle main, multi-stage flash (MSF) distillation transfer line, and seawater intake manifold.
5. Pharmaceutical and Food Processing
ASTM 358 Class 2 TP316L EFW Pharma pipes with electropolished inside finish used in large bore WFI water ring main, clean steam header, and distribution of process utility in the GMP manufacturing facilities.
6. Pulp, Paper and Fertiliser plants
904L and TP317L EFW bleach plant header pipes, digester connection pipes, sulphuric acid transfer mains, and process lines in fertiliser and chemical plants using concentrated inorganic acids.
7. Shipbuilding & Marine
Super duplex 2507 EFW seawater cooling water and ballast water main piping, fire main risers, and treatment system header of a ballast water treatment system on FPSO vessels and offshore platforms.
8. Construction & Industrial Infrastructure
TP304 Class 2 or Class 5 EFW pipes used in large bore structure columns, silo structures, architectural features elements and industrial infrastructure where diameter specifications are above ERW production range.
RFQ Checklist — What to Include:
- Standard — ASTM A358 / ASME SA358 + Class (1, 2, 3, 4, or 5)
- Grade — TP304, TP304L, TP316, TP316L, TP317L, TP321, TP321H, TP347, 904L, Duplex 2205, or other
- Size — NPS in inches + wall schedule (e.g., 16" SCH 40S) OR OD × wall thickness in mm
- Quantity — Number of pieces / metres / kilograms
- End Preparation — Plain end (PE) / Bevelled end (BE) per ASME B16.25
- Certification Required — EN 10204 3.1 MTC / 3.2 TPI / NACE / ASME BPVC documentation / PMI
- Radiographic Inspection — 100% RT / Spot RT / None (or specify class)
- Delivery Location — Port / city / country + required delivery date or lead time
Contact Our Sales Team:
📧 Email Your RFQ: sales@metinoxoverseas.com
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Related Stainless Steel Products
FAQs About Stainless Steel Pipe
An EFW stainless steel pipe (Electric Fusion Welded) is produced by rolling an austenitic stainless steel plate into a cylindrical form and joining the longitudinal seam by electric fusion welding using filler metal. Unlike ERW (electric resistance welding without filler metal used in ASTM A312), EFW uses filler metal in all weld passes, producing a stronger, more consistent weld seam with deeper penetration — making it suitable for large diameters, heavy walls, and high-temperature pressure service per ASTM A358.
ASTM A312 encompasses seamless and welded (ERW, without filler metal) austenitic stainless steel pipes in the NPS 1 /8 " to NPS 30" size ranges used in general corrosive and high temperature service. ASTM A358 applies to electric-fusion welded (EFW) pipes that use filler metal in applications of large diameter (NPS 8" to 72) that demand high-pressure and high temperature service and filler-metal welding and radiographic examination to ensure the integrity of the weld. The specified standard in case A312 seamless or ERW cannot be obtained at the necessary diameter or wall thickness is A358.
A358 304 is based on TP304 (C max 0.08) and is applicable to general corrosive and high temperature service. A358 304L incorporates TP304L base plate (C max 0.035%) - the low-carbon type - to avoid the possibility of sensitisation (carbide formation at the weld heat-affected positions) during the welding and post-wave heat-treatment. In the majority of applications that involve welding stainless steel EFW pipes on-site or post-welding heat treatment, A358 304L is used. In high temperature creep-range service A358 304H (high-carbon) is used instead.
Yes. Metinox Overseas is a manufacturer of stainless steel EFW pipe as well as a supplier of EFW pipe in India that manages the production of large-diameter EFW pipes in grades 304, 304L, 316, 316L, 317L, 321, 347, 904L, and duplex to ASTM A358 / ASME SA358 including Class 1 to Class 5. We are a manufacturer who has complete qualification of the welding procedure (WPS/PQR as required by the ASME Section IX) and also has the capability of radiographic testing as well as EN 10204 3.1 MTC issuance to serve the EPC contractors, refineries, power plants, and desalination projects of 40 or more countries.
Metinox stainless steel EFW pipes come in NPS 8" (OD 219 mm) to NPS 72" (OD 1,829 mm), with wall thicknesses of 3mm through 60mm in schedules SCH 5S, 10S, 40S and 80S - or by specification of wall per purchaser. Standard lengths Maximum length is 6,000 mm; custom cut lengths. Under NPS 8 inches in size, it is recommended that the ERW welded pipe, as specified in ASTM A312, or the seamless pipe, as specified in ASTM A312 can be used.
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