Home > Welded Pipes > ASTM A358 / SA358
Inox Steel India is a leading manufacturer and exporter of large-diameter Stainless Steel EFW Pipes produced as per ASTM A358 / ASME SA358 in grades 304/304L, 316/316L, 310, 321, and 347. These pipes are engineered for high-temperature, high-corrosion, and high-pressure service, making them ideal for refineries, petrochemicals, power plants, HRSG systems, oil & gas projects, and heavy industrial applications.
ASTM A358 pipes are typically used in critical environments where seamless or ERW pipes cannot meet diameter or performance needs. Large-bore EFW pipes (16” to 60” OD) are formed from stainless steel plates, welded using Electric Fusion Welding, and then solution annealed to ensure corrosion resistance and weld integrity equal to base metal.
Inox Steel India supplies EFW stainless steel pipes globally for steam lines, process piping, exhaust systems, heat recovery units, cracking units, desalination plants, and various high-temperature utilities.
EFW (Electric Fusion Welded) pipes are manufactured by forming stainless steel plates into cylindrical shape and welding the seam using electric fusion, producing full penetration, high-integrity welds suitable for large diameter and high-pressure use.
Key Characteristics:
EFW pipes are widely used where seamless pipes are impractical or unavailable in larger diameters.
Types of ASTM A358 Pipes We Manufacture
✔ Class 1 — Double-welded, radiographed, solution annealed
For high-pressure, high-temperature applications.
✔ Class 2 — Double-welded, no RT
For medium pressure service.
✔ Class 3 — Single-welded, radiographed, solution annealed
For critical service requiring radiographic testing.
✔ Class 4 — Double-welded, spot RT, solution annealed
Used in process industries.
✔ Class 5 — Double-welded, cold worked
Provides enhanced mechanical strength.
1️⃣ Raw Material Selection
Stainless steel plates confirmed through PMI testing.
2️⃣ Plate Edge Preparation
Machined edges ensure full penetration during welding.
3️⃣ Plate Rolling
Plates are rolled into pipe form with precise roundness & control.
4️⃣ Electric Fusion Welding (EFW)
A high-energy electrical arc fuses the edges to create a full-penetration weld.
5️⃣ Internal / External Weld Bead Treatment
Grinding or removal as per application need.
6️⃣ Solution Annealing
Restores corrosion resistance, removes heat tint & relieves stress.
7️⃣ Pickling & Passivation
Ensures clean, corrosion-resistant surface finish.
8️⃣ NDT Testing (as per Class 1–5)
RT / UT / EC tests depending on pipe class and specification.
9️⃣ Hydrostatic Testing
Mandatory test at required pressure levels.
🔟 Final Inspection & Marking
Grade, OD, WT, Class, Heat No., ASTM A358 marking.
Refineries & Petrochemical Plants
Used for high-temp steam, distillation units, cracking units & process piping.
Power Plants & HRSG (Heat Recovery Steam Generators)
Large-diameter stainless steel EFW pipes essential for HRSG ducts & piping.
Oil & Gas (High Temperature/Low Pressure Utilities)
Transporting hot fluids, exhaust gases & utility lines.
Fertilizer & Chemical Processing
Handles corrosive fluids, hot gases & pressure cycles.
Desalination & Marine Utilities
316/316L EFW pipes resist chloride corrosion.
Structural Industrial Applications
Support structures, exhaust stacks & heavy fabrication.
ASTM A358 / SA358 defines Electric Fusion Welded (EFW) Stainless Steel Pipes, primarily used for large diameter piping in high-temperature and corrosive environments. These pipes are manufactured from stainless steel plates using fusion welding, followed by solution annealing, pickling, and mandatory NDT, depending on the Class requirement (Class 1–5).
EFW pipes offer structural strength, dimensional precision, and corrosion resistance equivalent to seamless pipes but in much larger diameters, making them indispensable for refineries, petrochemical units, power plants, HRSGs, and chemical processing facilities.
Inox Steel India manufactures and supplies all five classes of ASTM A358, ensuring full compliance with weld quality, radiographic standards, and mechanical properties.
| Parameter / Property | SS EFW Pipes – TP304 / 304L | SS EFW Pipes – TP316 / 316L | Standard Requirements – ASTM A358 / SA358 |
|---|---|---|---|
| Material Type | Austenitic Stainless Steel | Austenitic Stainless Steel (Mo-added) | Electric Fusion Welded Stainless Steel Pipes |
| Grades Covered | TP304 / 304L | TP316 / 316L | Also includes 310, 321, 347 |
| Manufacturing Standard | ASTM A358 Class 1–5 | ASTM A358 Class 1–5 | Mandatory EFW welding + heat treatment |
| Weld Process | EFW (Electric Fusion Welded) | EFW (Electric Fusion Welded) | Full penetration welds |
| Diameter Capability | Large OD (16″ – 60″ or custom) | Large OD (16″ – 60″ or custom) | Large bore pipes |
| Corrosion Resistance | Good | Excellent (Mo improves chloride resistance) | As per ASTM |
| Key Composition | 18% Cr, 8% Ni | 16–18% Cr, 10–14% Ni, 2–3% Mo | ASTM chemical limits |
| Weld Heat Treatment | Solution Annealed | Solution Annealed | Mandatory for Class 1, 3, 4 |
| Mechanical Strength (TS) | 515–690 MPa | 515–690 MPa | As per grade |
| Yield Strength (YS) | 205 MPa | 205 MPa | As specified |
| NDT Requirements | RT / UT / Eddy Current | RT / UT / Eddy Current | Depends on class |
| Hydro Test | Required | Required | Mandatory |
| Classes Available | Class 1–5 | Class 1–5 | Defines weld testing levels |
| Weld Integrity | Full penetration weld | Full penetration weld | Essential requirement |
| Surface Finish | Pickled / Annealed / Polished | Pickled / Annealed / Polished | ASTM compliant |
| OD Range | 16” – 60” (customizable) | 16” – 60” (customizable) | Large-bore |
| Wall Thickness | SCH 10 – SCH 160 / Custom | SCH 10 – SCH 160 / Custom | Based on application |
| Typical Applications | Refineries, HRSG, Chemical, Power Plants | Marine, Desalination, Petrochemicals | High-temp & corrosive service |
| Testing Documentation | MTC 3.1 / RT films / UT reports | MTC 3.1 / RT films / UT reports | Required |
| HSN Code | 7306.40 | 7306.40 | SS welded pipes |
✔ TP304 / TP304L
✔ TP316 / TP316L
✔ TP310
✔ TP321
✔ TP347
| Class | Weld Type | Testing Requirements | Applications |
|---|---|---|---|
| Class 1 | Double-welded | 100% Radiography + Solution Annealed | High-pressure, high-temperature |
| Class 2 | Double-welded | No RT | Medium pressure applications |
| Class 3 | Single-welded | 100% RT + Solution Annealed | Critical process piping |
| Class 4 | Double-welded | Spot RT + Solution Annealed | Chemical / Petrochemical |
| Class 5 | Double-welded | Cold worked after welding | High-strength piping |
✔ For high-temperature piping (Furnaces, HRSG, exhaust systems)
→ Choose TP310 / TP321 / TP347
✔ For chemical, petrochemical & refinery pipelines
→ Choose TP316 / TP316L
✔ For general industrial service
→ Choose TP304 / TP304L
✔ For cyclic temperature fluctuations
→ Choose TP347
✔ For seawater utilities
→ Choose TP316L
| Parameter | Capability |
|---|---|
| Outside Diameter (OD) | 16” – 60” (Custom up to 80”) |
| Wall Thickness | SCH 10 – SCH 160 / Custom Heavy Wall |
| Length | 6 m / 12 m / Custom |
| Weld Type | EFW (Electric Fusion Welded) |
| Finish | Pickled, Annealed, Polished |
| Ends | Bevelled / Plain Ends |
| Form | Round |
| Grade | Price (INR/kg) | Price (USD/kg) |
|---|---|---|
| TP304 / TP304L EFW Pipes | ₹ 300 – ₹ 450 | $ 4.0 – $ 6.0 |
| TP316 / TP316L EFW Pipes | ₹ 420 – ₹ 600 | $ 5.5 – $ 8.0 |
| TP310 / TP321 / TP347 EFW Pipes | ₹ 500 – ₹ 750 | $ 6.5 – $ 10.0 |
| Large Diameter Custom Fabrication | On Request | On Request |
Pricing varies based on OD, thickness, Class (1–5), RT requirements, and documentation.
7306.40 — Stainless Steel Welded Pipes
✔ Mandatory Tests (As per ASTM A358 Class)
✔ Mechanical Tests
✔ Additional Tests (on request)
✔ Documentation Provided
✔ Third-Party Inspection (TPI) Available
SGS • BV • DNV • TÜV • Lloyd’s
Inox Steel India exports ASTM A358 EFW Pipes to:
Middle East:
Africa:
Europe:
Americas:
Asia Pacific:
Used in refineries, petrochemical plants, HRSG units, chemical processing, and industrial utility systems globally.
Large-bore stainless steel piping demands precision welding, full-penetration fusion seams, radiographic testing, and accurate dimensional control. Inox Steel India has established itself as a reliable supplier of ASTM A358 / SA358 EFW pipes for global EPC contractors, refineries, petrochemical plants, and power companies.
Why our A358 EFW pipes stand out:
Inox Steel India is trusted by refineries, chemical plants, HRSG manufacturers, desalination units, offshore platforms, and industrial EPC companies worldwide.
Refineries & Petrochemical Plants
Used for steam lines, reformer tubes, hydrogen lines, cracking units, and high-temp fluid service.
Power Plants / HRSG Systems
Large-bore EFW pipes are critical for ducting, boiler piping, steam distribution, and high-temperature exhaust handling.
Chemical Processing
A358 pipes handle corrosive fluids, acids, solvents, and hot vapors reliably.
Oil & Gas (Onshore & Offshore)
Used for utility lines, flare systems, exhaust systems, and high-temperature processing.
Desalination Plants
316L pipes resist chloride-rich environments in intake/outlet lines.
Furnaces & Heat Exchanger Shells
310/321/347 grades withstand high oxidation & thermal cycling.
Structural Industrial Applications
Large-diameter stainless pipes used as columns, stacks, ducts, and fabrications.
Large-bore EFW pipes require secure loading, surface protection, and rust-prevention packing.
✔ Standard Packing
✔ Heavy Industrial Packing
✔ Export Packing
✔ Ports of Dispatch
✔ Export Markets
Looking for ASTM A358 Stainless Steel EFW Pipes for refineries, power plants, HRSG units, chemical or petrochemical applications?
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
steel@inoxsteelindia.in
+91 9930796690
Inox Steel India
Email
Phone
They define weld type, RT requirement, and heat treatment.
(Class 1 & 3 = 100% RT, Class 2 = No RT, Class 4 = Spot RT, Class 5 = Cold worked)
Yes — especially TP310, TP321, TP347.
Yes — provided for Classes 1 & 3.
Yes — up to 60” or 80” OD.
Yes — to Middle East, Europe, USA, Africa & Asia.
We provide complete technical support, documentation, and global delivery.