EFW Pipe
Electric-fusion-welded (EFW) pipe — filler-welded for larger diameters and heavier walls — in carbon, alloy and stainless grades to ASTM/ASME.
Technical specification
| Parameter | Specification |
|---|---|
| Product | Electric-fusion-welded (EFW) pipe — plate / coil rolled and seam-welded with filler metal |
| Manufacturing route | EFW; submerged-arc welding (SAW) where specified. “LSAW” is a longitudinal SAW seam that overlaps EFW / SAW terminology, not a separate material. |
| Dimensional standard | ASME B36.10M (carbon / alloy) · B36.19M (stainless / duplex); or custom OD × plate thickness |
| Size range | Typically NPS 6 and larger (plate-formed), grade / class-specific — smaller sizes via ERW or seamless |
| Wall / class | Standard schedule or custom OD × plate thickness; product class per the specification — not a universal range |
| Material specifications | ASTM A671, A672, A691 (carbon / alloy EFW); A358 (stainless EFW); A928 (duplex EFW, with filler) |
| Sour service | NACE MR0175 / ISO 15156 where qualified — not implied by API PSL2 alone |
| Documentation | EN 10204 3.1 / 3.2, PMI, plate & weld traceability |
How it is made
EFW pipe is made by rolling plate or coil into a cylinder and joining the seam with filler metal by a fusion process such as submerged-arc welding (SAW). EFW is a manufacturing category, not a single welding process; SAW is used where specified, and “LSAW” describes a longitudinal SAW seam that overlaps EFW / SAW terminology rather than being a separate material. The seam may be single- or double-welded and is examined by radiography to the extent the product class requires — complete, spot, or not required by the class — and stress-relieved or fully heat-treated per the order. Weld-joint efficiency and design factors are assigned by the applicable construction code from the product, joint construction, examination and temperature — radiography alone does not create a universal 100 % RT or a 1.0 factor, and a compliant weld is not a certified pressure vessel. Schedule or class defines a nominal wall, not a pressure rating; the actual wall follows the B36.10M / B36.19M table or the ordered OD × plate thickness.
ASTM A358 stainless classes
| Class | Weld configuration | Radiography |
|---|---|---|
| Class 1 | Double-welded (filler both sides) | Complete (100 %) |
| Class 2 | Double-welded | Not required by class |
| Class 3 | Single-welded | Complete (100 %) |
| Class 4 | Class 3 with a permitted no-filler inside pass | Complete (100 %) |
| Class 5 | Double-welded | Spot |
ASTM A928 duplex EFW
| Radiography | Construction |
|---|---|
| Complete | Filler-welded, solution heat-treated |
| Spot | Filler-welded, solution heat-treated |
| Not required by class | Filler-welded, solution heat-treated |
Grades & materials
EFW specifications and representative grades below. EFW pipe is defined by a pipe grade, a source plate grade and a class; availability by grade, class and size is confirmed on quotation. Seamless-only specifications (A106, A335) are covered on the seamless pipe page.
| Family | Grades | Standard | Service |
|---|---|---|---|
| Carbon EFW (atmospheric / low-temp) | A671 CA55, CB60 / 65 / 70, CC60 / 65 / 70, CD70 / 80, CE55 / 60 | ASTM A671 | Atmospheric & lower-temp |
| Carbon EFW (high-pressure) | A672 B60 / 65 / 70, C60 / 65 / 70, D70 / 80 | ASTM A672 | Moderate-temp, higher pressure |
| Carbon / alloy EFW (high-temp) | A691 CM, 1Cr, 1¼Cr, 2¼Cr, 5Cr, 9Cr | ASTM A691 | High-temperature |
| Austenitic stainless EFW | A358 TP304 / 304L / 316 / 316L / 321 / 347 / 310S (Cl.1–5) | ASTM A358 | Corrosion / high temp |
| Duplex EFW | A928 S31803 / S32205 (2205), S32750 (2507) | ASTM A928 | Chloride / sour |
A671 / A672 / A691 — pipe grade, source plate & class
| Specification | Example pipe grades | Source plate | Class governs | Service |
|---|---|---|---|---|
| ASTM A671 | CB60 / 65 / 70, CC60 / 65 / 70, CD70 / 80 | A515 / A516 / A537 | Heat treatment & radiography (Cl.10–33) | Atmospheric / lower-temp |
| ASTM A672 | B60 / 65 / 70, C60 / 65 / 70, D70 / 80 | A515 / A516 / A537 | Heat treatment & radiography by class | Moderate-temp, high pressure |
| ASTM A691 | CM, 1¼Cr, 2¼Cr, 5Cr, 9Cr | A204 (C-Mo), A387 (Cr-Mo) | Heat treatment & radiography by class | High-temperature |
Chemical composition (representative)
| Grade | Spec / plate | C | Mn | Si | P max | S max | Cr | Ni | Mo | Other |
|---|---|---|---|---|---|---|---|---|---|---|
| A671 CC70 / A672 C70 | A516-70 plate | 0.30 max | 0.85–1.20 | 0.15–0.40 | 0.030 | 0.030 | — | — | — | plate A516 Gr.70 |
| A671 CB70 / A672 B70 | A515-70 plate | 0.31 max | 0.90 max | 0.15–0.40 | 0.030 | 0.030 | — | — | — | plate A515 Gr.70 |
| A671 CD80 / A672 D80 | A537 Cl.2 plate | 0.24 max | 0.70–1.60 | 0.15–0.55 | 0.035 | 0.035 | — | — | — | plate A537 |
| A691 1¼Cr | A387-11 plate | 0.05–0.17 | 0.40–0.65 | 0.50–0.80 | 0.035 | 0.035 | 1.00–1.50 | — | 0.45–0.65 | — |
| A691 2¼Cr | A387-22 plate | 0.05–0.15 | 0.30–0.60 | 0.50 max | 0.035 | 0.035 | 2.00–2.50 | — | 0.90–1.10 | — |
| A691 5Cr | A387-5 plate | 0.15 max | 0.30–0.60 | 0.50 max | 0.035 | 0.030 | 4.00–6.00 | — | 0.45–0.65 | — |
| A691 9Cr | A387-91 plate | 0.08–0.12 | 0.30–0.60 | 0.20–0.50 | 0.020 | 0.010 | 8.0–9.5 | 0.40 max | 0.85–1.05 | V 0.18–0.25, Nb 0.06–0.10, N 0.03–0.07 |
| A358 TP304L | A358 | 0.035 max | 2.00 max | 1.00 max | 0.045 | 0.030 | 18.0–20.0 | 8.0–13.0 | — | — |
| A358 TP316L | A358 | 0.035 max | 2.00 max | 1.00 max | 0.045 | 0.030 | 16.0–18.0 | 10.0–15.0 | 2.0–3.0 | — |
| A358 TP321 | A358 | 0.08 max | 2.00 max | 1.00 max | 0.045 | 0.030 | 17.0–19.0 | 9.0–13.0 | — | Ti 5×(C+N)–0.70 |
| A358 TP347 | A358 | 0.08 max | 2.00 max | 1.00 max | 0.045 | 0.030 | 17.0–19.0 | 9.0–13.0 | — | Nb 10×C–1.00 |
| A358 TP310S | A358 | 0.08 max | 2.00 max | 1.50 max | 0.045 | 0.030 | 24.0–26.0 | 19.0–22.0 | — | — |
| A928 S31803 | A928 | 0.030 max | 2.00 max | 1.00 max | 0.030 | 0.020 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | N 0.08–0.20 |
| A928 S32205 | A928 | 0.030 max | 2.00 max | 1.00 max | 0.030 | 0.020 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | N 0.14–0.20 |
| A928 S32750 | A928 | 0.030 max | 1.20 max | 0.80 max | 0.035 | 0.020 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | N 0.24–0.32 |
Standards & specifications
Dimensional & product
- ASME B36.10M carbon / alloy · B36.19M stainless / duplex; or custom OD × plate thickness
- ASTM A671 / A672 EFW carbon — atmospheric / high-pressure
- ASTM A691 EFW carbon / alloy — high-temperature
- ASTM A358 stainless EFW (Cl.1–5) · A928 duplex EFW (with filler)
Class, testing & service
- Class governs weld configuration, radiography (complete / spot / not required) & heat treatment
- Weld-joint efficiency & design factor from the construction code — not a universal 1.0
- RT and UT are not automatically interchangeable; a no-RT class is still inspected
- NACE MR0175 / ISO 15156 where qualified — not implied by PSL2
- A928 (with filler) ≠ A790 (no filler); see welded pipe
Mechanical properties (representative grades)
Representative grades — full MTC values on request. Values are specification minima or ranges at room temperature; for carbon / alloy EFW they track the parent plate grade. Transverse weld tensile and guided-bend tests also apply; cryogenic service needs qualified toughness at the design temperature, not a general Charpy note.
| Grade | Basis | Tensile (MPa) | Yield min (MPa) | Elong min (%) |
|---|---|---|---|---|
| A671 CC65 / A672 C65 | A516-65 plate | 450–585 | 240 | 23 |
| A671 CC70 / A672 C70 | A516-70 plate | 485–620 | 260 | 21 |
| A671 CB70 / A672 B70 | A515-70 plate | 485–620 | 260 | 21 |
| A671 CD80 / A672 D80 | A537 Cl.2 plate | 550–690 | 415 | 22 |
| A691 1¼Cr | A387-11 Cl.2 | 515–690 | 310 | 22 |
| A691 2¼Cr | A387-22 Cl.2 | 515–690 | 310 | 18 |
| A691 5Cr | A387-5 Cl.2 | 515–690 | 310 | 18 |
| A691 9Cr | A387-91 | 585–760 | 415 | 20 |
| A358 TP304 / 304H | Austenitic SS | 515 min | 205 | 35 |
| A358 TP304L | Austenitic SS | 485 min | 170 | 35 |
| A358 TP316 / 316H | Austenitic SS | 515 min | 205 | 35 |
| A358 TP316L | Austenitic SS | 485 min | 170 | 35 |
| A358 TP321 | Austenitic SS | 515 min | 205 | 35 |
| A358 TP347 | Austenitic SS | 515 min | 205 | 35 |
| A358 TP310S | Austenitic SS | 515 min | 205 | 35 |
| A928 S31803 (2205) | Duplex | 620 min | 450 | 25 |
| A928 S32205 (2205) | Duplex | 655 min | 485 | 25 |
| A928 S32750 (2507) | Super duplex | 795 min | 550 | 15 |
Testing, inspection & documentation
| Test / document | Detail |
|---|---|
| Chemical / PMI | Parent and, where specified, weld-metal chemistry; PMI on alloy / stainless / duplex. PMI does not replace full chemistry. |
| Tensile (base & weld) | Base-metal and transverse weld tensile (ASTM A370) |
| Guided-bend | Guided-bend for weld ductility |
| Impact (Charpy) | Grade / procedure / HAZ at the design temperature — a general Charpy note does not qualify cryogenic service |
| Radiography | Complete, spot or not-required-by-class per the product class (A358, A928, A671 / A672 / A691). RT and UT are not automatically interchangeable. |
| Hydrostatic | Hydrotest to the product standard |
| Corrosion | IGC per ASTM A262 where specified (austenitic); ferrite / phase balance (duplex) |
| Certification | EN 10204 3.1 as standard; 3.2 validated by an independent authorised party |
Applications & industries served
Dimensions, schedules & theoretical weight
EFW pipe is supplied to a standard schedule or, commonly, as custom OD × plate thickness. Mass is kg/m = π × t × (D − t) × ρ × 10⁻⁶ (carbon-steel basis ρ = 7850 kg/m³); lb/ft ≈ kg/m × 0.672; nominal ID = D − 2t. Figures exclude weld reinforcement, coating and lining. EFW is typically NPS 6 and larger; a specification’s size scope is not a confirmed supply range — availability by grade, class and size is confirmed on RFQ.
Carbon & alloy steel — ASME B36.10M
| NPS | OD (mm) | STD | XS | Sch 160 | XXS | ||||
|---|---|---|---|---|---|---|---|---|---|
| t | kg/m | t | kg/m | t | kg/m | t | kg/m | ||
| 1/2 | 21.3 | 2.77 | 1.27 | 3.73 | 1.62 | 4.78 | 1.95 | 7.47 | 2.55 |
| 3/4 | 26.7 | 2.87 | 1.69 | 3.91 | 2.20 | 5.56 | 2.90 | 7.82 | 3.64 |
| 1 | 33.4 | 3.38 | 2.50 | 4.55 | 3.24 | 6.35 | 4.24 | 9.09 | 5.45 |
| 1-1/4 | 42.2 | 3.56 | 3.39 | 4.85 | 4.47 | 6.35 | 5.61 | 9.70 | 7.77 |
| 1-1/2 | 48.3 | 3.68 | 4.05 | 5.08 | 5.41 | 7.14 | 7.25 | 10.15 | 9.55 |
| 2 | 60.3 | 3.91 | 5.44 | 5.54 | 7.48 | 8.74 | 11.1 | 11.07 | 13.4 |
| 2-1/2 | 73.0 | 5.16 | 8.63 | 7.01 | 11.4 | 9.53 | 14.9 | 14.02 | 20.4 |
| 3 | 88.9 | 5.49 | 11.3 | 7.62 | 15.3 | 11.13 | 21.3 | 15.24 | 27.7 |
| 4 | 114.3 | 6.02 | 16.1 | 8.56 | 22.3 | 13.49 | 33.5 | 17.12 | 41.0 |
| 6 | 168.3 | 7.11 | 28.3 | 10.97 | 42.6 | 18.26 | 67.6 | 21.95 | 79.2 |
| 8 | 219.1 | 8.18 | 42.5 | 12.70 | 64.6 | 23.01 | 111.3 | 22.23 | 107.9 |
| 10 | 273.0 | 9.27 | 60.3 | 12.70 | 81.5 | 28.58 | 172.3 | 25.40 | 155.1 |
| 12 | 323.8 | 9.53 | 73.9 | 12.70 | 97.4 | 33.32 | 238.7 | 25.40 | 186.9 |
| 14 | 355.6 | 9.53 | 81.3 | 12.70 | 107.4 | 35.71 | 281.7 | — | — |
| 16 | 406.4 | 9.53 | 93.3 | 12.70 | 123.3 | 40.49 | 365.4 | — | — |
| 18 | 457.0 | 9.53 | 105.2 | 12.70 | 139.2 | 45.24 | 459.4 | — | — |
| 20 | 508.0 | 9.53 | 117.2 | 12.70 | 155.1 | 50.01 | 564.8 | — | — |
| 24 | 610.0 | 9.53 | 141.1 | 12.70 | 187.1 | 59.54 | 808.3 | — | — |
Stainless & duplex — ASME B36.19M
| NPS | OD (mm) | Sch 5S | Sch 10S | Sch 40S | Sch 80S | ||||
|---|---|---|---|---|---|---|---|---|---|
| t | kg/m | t | kg/m | t | kg/m | t | kg/m | ||
| 1/2 | 21.3 | 1.65 | 0.80 | 2.11 | 1.00 | 2.77 | 1.27 | 3.73 | 1.62 |
| 3/4 | 26.7 | 1.65 | 1.02 | 2.11 | 1.28 | 2.87 | 1.69 | 3.91 | 2.20 |
| 1 | 33.4 | 1.65 | 1.29 | 2.77 | 2.09 | 3.38 | 2.50 | 4.55 | 3.24 |
| 1-1/4 | 42.2 | 1.65 | 1.65 | 2.77 | 2.69 | 3.56 | 3.39 | 4.85 | 4.47 |
| 1-1/2 | 48.3 | 1.65 | 1.90 | 2.77 | 3.11 | 3.68 | 4.05 | 5.08 | 5.41 |
| 2 | 60.3 | 1.65 | 2.39 | 2.77 | 3.93 | 3.91 | 5.44 | 5.54 | 7.48 |
| 2-1/2 | 73.0 | 2.11 | 3.69 | 3.05 | 5.26 | 5.16 | 8.63 | 7.01 | 11.4 |
| 3 | 88.9 | 2.11 | 4.52 | 3.05 | 6.46 | 5.49 | 11.3 | 7.62 | 15.3 |
| 4 | 114.3 | 2.11 | 5.84 | 3.05 | 8.37 | 6.02 | 16.1 | 8.56 | 22.3 |
| 6 | 168.3 | 2.77 | 11.3 | 3.40 | 13.8 | 7.11 | 28.3 | 10.97 | 42.6 |
| 8 | 219.1 | 2.77 | 14.8 | 3.76 | 20.0 | 8.18 | 42.5 | 12.70 | 64.6 |
| 10 | 273.0 | 3.40 | 22.6 | 4.19 | 27.8 | 9.27 | 60.3 | 12.70 | 81.5 |
| 12 | 323.8 | 3.96 | 31.2 | 4.57 | 36.0 | 9.53 | 73.9 | 12.70 | 97.4 |
Provide with your enquiry
- Specification / edition, grade and class.
- OD and wall / plate thickness (or schedule), seam arrangement.
- Length, ends, final treatment and examination scope.
And the commercial detail
- Required tests and certification (3.1 / 3.2, PMI, NACE).
- Service & design conditions, source restrictions.
- Quantity, coating / lining, delivery location and any BOQ.
Frequently asked questions
What is EFW pipe?
EFW (electric-fusion-welded) pipe is made by rolling plate into a cylinder and joining the seam with filler metal by a fusion-welding process such as SAW. It is a manufacturing category, not a single material — carbon (A671 / A672), alloy (A691) and stainless (A358) grades are all made this way, each with its own grade, class, plate basis, treatment and examination.
Is A358 Class 1 the “highest” class, and are Classes 2–5 lower quality?
No — the classes are not a descending performance ranking. They differ by welding configuration and radiography: Class 1 is double-welded with complete radiography, Class 2 is double-welded but radiography is not required by the class, Class 3 is single-welded with complete radiography, Class 4 is Class 3 with a permitted no-filler inside pass, and Class 5 is double-welded with spot radiography. Heat treatment is a separate order requirement, and a “no-RT” class still has other inspections.
Is EFW pipe always 100% radiographed with a joint efficiency of 1.0?
No. Radiography depends on the specification and class (complete, spot, or not required by the class), and additional order requirements can change the scope. Weld-joint efficiency and design factors are assigned by the applicable design code from the product, joint construction, examination and temperature — radiography alone does not create a universal 1.0 factor or a pressure rating, and a compliant weld does not by itself certify a finished pressure vessel.
What is the difference between A671, A672 and A691?
They cover different service. A671 is EFW carbon pipe for atmospheric and lower-temperature service, A672 is EFW carbon pipe for high-pressure service at moderate temperatures, and A691 is EFW carbon / alloy pipe for high-temperature service. They also use different grade / class systems (for example A671 CC-grades vs A672 B-grades vs A691 chromium grades), so the exact grade and class are confirmed per order.
Can EFW pipe be used for cryogenic / LNG service?
Only with the appropriate grade, welding procedure, heat treatment and toughness acceptance at the actual design temperature — a general mention of Charpy testing is not sufficient. Low-temperature qualification requires the specified test temperature, specimen size and orientation, and the energy or lateral-expansion acceptance criteria, all confirmed for the design condition.
What sizes and walls do you supply?
EFW pipe is offered from about NPS 6, in grade / class-specific combinations; it is often specified by actual OD × plate thickness rather than a schedule. Larger or heavier custom sizes are subject to technical review — plate width is only one constraint, alongside forming, welding, heat-treatment and NDE capability — so a firm size / wall / grade combination is confirmed per order rather than assumed from a range.
What information is needed for a quotation?
Provide the standard and edition, grade and class, dimensions (OD and wall / plate thickness, or schedule), seam arrangement, length and quantity, final treatment, examination scope, service and design conditions, ends, finish, documentation and delivery requirements. Availability by grade, class and size is confirmed with the quotation.
Request a quote
Send your requirement to Sagiant Piping Industries and our team responds with grade, material selection, availability and pricing for efw pipe. Attach a BOQ, line list or drawing for a faster, more accurate quotation.
- Fast RFQ response with grade & material-selection support
- EN 10204 3.1 / 3.2 certification, PMI & third-party inspection
- BOQ & line-list project supply — India & export
Mechanical & chemical values shown are ASTM/ASME specification figures; certified heat-specific values appear on the MTC. Availability is confirmed with the quotation.
