Seamless Galvanized Steel Pipe & Tube
We supply galvanized seamless pipe for high pressure and heavy wall lines. The base pipe is seamless to ASTM A106 or A53 Type S, then hot-dip galvanized inside and out. Sizes run from 1/2" to 24", Sch 40 to XXS.
No weld seam, so no weak line under pressure or bending
Base pipe with heat numbers traced to the zinc lot
Zinc coating of 420 g/m² minimum, tested per lot
Plain, beveled or threaded ends. Fixed lengths: 5.8 m, 6 m, 12 m. Single Random Length (SRL: 4.88–6.71 m) and Double Random Length (DRL: 10.67–13.1 m) available. Custom cut lengths upon request
Why Order GI Seamless Pipe From Us
01
Real Seamless, Proven
Every lot ships with the base pipe mill certificate showing the seamless process.
02
Heavy Walls in Stock
Seamless covers walls that welded pipe rarely reaches, such as Sch 80, Sch 160 and XXS.
03
One Certificate Chain
Base pipe and galvanizing are linked by heat number and coating lot. You can trace each length from the mill to your site.
04
Ends Ready to Install
We cut, bevel and thread after galvanizing, then cap the ends.
Galvanized Seamless Steel Pipe for Pressure and Heavy Wall
Galvanized seamless steel pipe is pierced from a solid billet. It has no weld, so its strength is the same all the way round. Add a hot-dip zinc coat, and you get a pressure pipe that also resists rust.
You will find it in high-pressure fire mains, ship piping and mine water lines. It also fits jobs where the pipe is bent, flared or threaded with a deep cut. In those cases, a weld seam is the first place a crack starts.
Seamless Galvanized Pipe & Tube Range
A106 Grade B Seamless, Hot-Dip Galvanized
For high-pressure water and fire lines. Sch 40 to XXS.
A53 Type S Grade B Galvanized
The seamless form of A53. Common where specs name A53 but ban the weld seam.
Heavy Wall Seamless GI Pipe
Sch 80, Sch 160 and XXS for mining, marine and hydraulic service.
Seamless Galvanized Tube by OD
Cold-drawn or hot-rolled tube by OD × wall, for machine parts and frames.
Specifications
| Item | Range |
|---|---|
| Size | 1/2″ – 24″ (DN15 – DN600); OD 21.3 – 610 mm |
| Wall | Sch 40, Sch 80, Sch 160, XXS; 2.5 – 26 mm |
| Base pipe | ASTM A106 Gr. B, A53 Type S Gr. B, API 5L, GB/T 8163 |
| Coating | Hot-dip, 420 g/m² minimum |
| Ends | Plain, bevelled, threaded and coupled |
| Length | 5.8 m, 6 m, 12m, or as requested |
When Seamless Galvanized Pipe Is Worth It
Seamless galvanized pipe costs more than welded and takes longer to make. For most water, fence and structural jobs, ERW galvanized pipe does the work. So the real question is when to pay for seamless.
Choose Seamless When
- Your spec bans a weld seam. Many marine, mining and high-pressure fire specs do.
- The wall is Sch 80 or heavier. Welded pipe in heavy walls is hard to find in small sizes.
- The pipe will be bent tightly, flared or deep threaded.
- Pressure is high and the pipe runs where a failure is costly.
Choose Welded When
For Sch 40 water lines, sprinklers and structures, ERW galvanized pipe meets the same A53 strength. It costs less and ships faster. See ERW Galvanized Steel Pipe & Tube.
How to Make Sure It Is Really Seamless
Some offers call welded pipe “seamless”. Check the base pipe certificate. It should name A106, A53 Type S, or another seamless standard. Look inside the bore with a light. Welded pipe may show a straight line. A cut ring etched with acid shows the weld clearly.
Watch the Temperature
Zinc coating is sensitive to high temperatures. With continuous service above approximately 200°C, the galvanized layer may peel away from the steel substrate. Therefore, galvanized seamless pipe is not recommended for steam or hot oil lines. For such high-temperature service, use black seamless pipe.
Lead Time and Order Size
Seamless galvanized pipe is often made to order. Base pipe is bought, cut and sent to the galvanizer. Plan 3-4 weeks, and expect a minimum order per siz. Stock heavy-wall sizes ship faster. We keep 9,000 tons of galvanized pipe & tube in stock (out of 80,000 tons in total).
Frequently Asked Questions
Is GI pipe seamless or welded?
Most GI pipe is welded (ERW). Seamless GI pipe is a smaller, special product. If your drawing just says "GI pipe", welded is usually fine. Ask for seamless only when the spec or the service needs it.
What standard is galvanized seamless pipe made to?
The steel pipe follows ASTM A106 Grade B or A53 Type S Grade B in most orders. The zinc coat follows A53 or ASTM A123 . Some markets use GB/T 8163 or EN 10216 base pipe.
Can seamless galvanized pipe be threaded?
Yes. We thread after galvanizing to NPT or BSP. Heavy-wall seamless pipe takes a deep thread well. Threads are capped for transit.
How much does seamless galvanized pipe cost?
Wall, size and quantity move the price. Send your list, and we will quote within 8 working hours.
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