ERW Galvanized Steel Pipe & Tube
We supply ERW GI pipe, welded by high frequency and galvanized for water, fire and structural use. Sizes run from NPS 1/8" to 26" and round OD 12.7–610 mm, in round, square and rectangular pipe & tube.
Weld seam flattening, hydro and eddy current tested
To ASTM A53 Type E, A135, A795, API 5L Gr. B, BS 1387 / EN 10255, EN 10219 and GB/T 3091
Hot-dip 300–600 g/m² after welding, or pre-galvanized 60–275 g/m² from GI coil
Inside weld bead removed on request for smooth flow
Why Order ERW Galvanized Pipe From Us
01
Weld Seam Tested on Every Length
Each length passes eddy current or hydro testing. Flattening and bend tests run per lot. The results go on the certificate.
02
Clear Specifications and Bundle Labels
ERW galvanized pipe & tube is supplied to agreed sizes, walls and standards. Each bundle is labelled, so you can check it against your order on arrival.
03
Your Choice of Coating
Hot-dip for water and outdoor lines. Pre-galvanized for dry frames and furniture. We advise which fits your use.
04
Large Volumes, Short Lead Time
ERW lines run fast. Typical lead time is 8–12 working days. We keep 9,000 tons of galvanized pipe & tube in stock (out of 80,000 tons in total). Mill orders for special walls take 2–3 weeks, depending on the order.
ERW Galvanized Steel Pipe: The Everyday Workhorse
Most galvanized pipe sold worldwide is ERW. The mill rolls steel strip into a tube. High-frequency current heats the edges, and rollers press them into one solid weld. No filler metal is added.
The result is a pipe with even wall, tight OD and a clean finish. It costs less than seamless and comes in longer runs. For Sch 40 water lines, sprinklers, fences and frames, ERW galvanized pipe is the sensible default.
ERW Galvanized Pipe & Tube Range
Hot-Dip ERW GI Pipe
Welded first, then dipped in zinc inside and out. For water, fire and irrigation. See Hot-Dip Galvanized Steel Pipe & Tube.
Pre-Galvanized ERW Pipe & Tube
Welded from zinc-coated strip, with the outside seam re-zinced. For frames, greenhouses and furniture.
ERW Square and Rectangular Tube
Box sections from the same lines, in pre-galvanized or hot-dip finish.
Schedule 40 ERW Galvanized Pipe
ASTM A53 Type E Grade B, threaded and coupled. See Schedule 40 Galvanized Pipe.
Specifications
| Item | Range |
|---|---|
| Size | NPS 1/8″ – 26″ (DN6 – DN650); round tube OD 12.7 – 610 mm |
| Wall | Sch 5 – Sch 160 / XXS (per size); BS 1387 L / M / H |
| Steel | ASTM A53 Gr. A / B, API 5L Gr. B, EN 10255 S195T, EN 10219 S235JRH / S355J2H, Q195–Q355B, STK400 / STK500 |
| Welding | High-frequency ERW (HFW) |
| Coating | Hot-dip 300–600 g/m²; pre-galvanized 60–275 g/m² (both sides); electro-galvanized 5–20 µm |
| Tests | Flattening, bend, hydrostatic, eddy current |
| Standards | ASTM A53 Type E, A135, A795, A500, API 5L, BS 1387, EN 10255, EN 10219, GB/T 3091, JIS G3444; zinc to EN 10240 / ISO 1461 |
| Length | 5.8 m / 6 m / 12 m; 20 ft / 21 ft / 40 ft; or cut to length; ends plain, bevelled, threaded & coupled or grooved |
How to Judge an ERW Galvanized Pipe Offer
Two offers for "ERW GI pipe" can be very different products. The weld, the coat and the wall decide what you really get. Here is what to check.
1. The Weld Seam
A good ERW weld is as strong as the pipe. A poor one splits under pressure or when threaded. Ask how the seam is tested. Eddy current on every length is standard. A flattening test per lot proves the weld is ductile. Hydro testing proves the pipe holds pressure.
If you cut grooves or deep threads, ask for the weld to be heat treated. It makes the seam less brittle.
2. Inside Bead
ERW leaves a small bead inside the pipe. For water and fire lines, it barely matters. For pipe you will push cables or rods through, or for hydraulic use, ask for the inside bead to be removed. It costs a little more.
3. Welded, Then Galvanized, or the Reverse?
This is the biggest difference between offers. Galvanized welded steel pipe can be dipped after welding (hot-dip) or welded from coated strip (pre-galvanized). Hot-dip covers the weld and the bore. Pre-galvanized leaves the inside weld nearly bare.
For any water line, insist on hot-dip. The coat is several times thicker, and the bore is protected. For dry frames, pre-galvanized is fine and cheaper.
4. Wall Tolerance
Some low offers use strip at the bottom of the tolerance. A “2.0 mm” pipe may measure 1.8 mm. Ask for the minimum wall in writing. Check a few pipes with a micrometer when they arrive.
5. When to Go Seamless Instead
ERW covers almost all galvanized pipe uses. Choose seamless only when your spec bans a weld, or the wall is very heavy. See Seamless Galvanized Steel Pipe & Tube. Above 26″, larger pipe is made by submerged arc welding (LSAW or SSAW) up to OD 2000 mm, not ERW.
Frequently Asked Questions
What does ERW mean on GI pipe?
ERW stands for electric resistance welded. The pipe is formed from strip and welded by high-frequency current, without filler metal. Most GI pipe is ERW. It is then hot-dip galvanized or made from pre-galvanized strip.
Is ERW galvanized pipe good for water lines?
Yes, if it is hot-dip galvanized after welding. The zinc then covers the bore and the weld. Check local codes for drinking water. Pre-galvanized ERW pipe is not suitable for water lines.
Is ERW galvanized steel pipe as strong as seamless?
For the same grade and wall, yes, in most uses. A53 Type E and Type S share the same strength grades. Seamless is preferred only for very high pressure, heavy walls or when a spec rules out welds.
How much does ERW galvanized pipe cost?
It is the lowest-cost galvanized pipe for most sizes. Price depends on size, wall, coating and quantity. Send your list, and we will quote within 2–4 working hours. Quotes are valid for 3 days.
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