Galvanized Steel Pipe
Hot-dip galvanized steel pipes with superior corrosion resistance for outdoor structures, fencing, water systems, and agricultural applications. Available in round, square, and rectangular shapes.
Galvanized Steel Pipe
Hot-dip galvanized steel pipes are manufactured by immersing steel pipes into a molten zinc bath, forming a metallurgically bonded zinc coating that provides outstanding corrosion resistance. This galvanizing process creates a robust barrier that protects the underlying steel from rust and oxidation.
Galvanized pipes are widely used in outdoor environments where exposure to moisture and harsh weather conditions is expected. They offer excellent durability, low maintenance costs, and extended service life compared to uncoated steel pipes.
Technical Specifications
| Specification | Round Pipe (ERW) | Square / Rectangular Tube |
|---|---|---|
| Outer Diameter | 4.76 – 1219 mm (1/8″ – 48″) | 15 × 15 – 400 × 400 mm |
| Wall Thickness | 0.5 – 16 mm | 0.5 – 12 mm |
| Length | 0.5 – 12 m or custom length | |
| Zinc Coating Weight | Class A: ≥300 g/m² | Class B: ≥450 g/m² | Class C: ≥600 g/m² | |
| Coating Thickness | 60 – 120 μm typical (up to 200 μm) | |
| Standard | Description |
|---|---|
| ASTM A53 / A123 | Standard specification for hot-dip galvanized pipe |
| BS 1387 | British standard for tubular steel tubes |
| EN 10217 / EN 10240 | European welded steel tube + internal coating standards |
| GB/T 3091 | Chinese standard for liquid delivery welded steel pipe |
| JIS G 3444 | Japanese standard for general structural purposes |
| ISO 1461 | International hot-dip galvanized coatings on iron/steel |
| Property | Value / Description |
|---|---|
| Zinc Purity | ≥98.5% pure zinc bath |
| Adhesion Test | Passes hammer test per ASTM A123 |
| Salt Spray Test | ≥500 hours without white rust (per ASTM B117) |
| Service Life | 20+ years in rural environment, 10–15 years in industrial areas |
| Tensile Strength | 290 – 520 MPa (depending on base material grade) |
| Elongation | ≥15% – 30% |
| Industry | Typical Applications |
|---|---|
| Construction | Scaffolding, handrails, fence posts, building frameworks, guardrails |
| Agriculture | Irrigation systems, greenhouse structures, livestock enclosures |
| Water Systems | Potable water supply, drainage, fire protection systems |
| Infrastructure | Highway guardrails, bridge railings, traffic barriers |
| Utilities | Utility poles, cable conduits, sign posts |
| General Engineering | Fabricated metal products, HVAC ductwork supports |
Manufacturing Process
Our galvanized steel pipes are produced through an integrated 12-step process combining precision ERW/SAW welding with hot-dip galvanizing to deliver superior corrosion protection and consistent coating quality.
Raw Material Inspection
Hot-rolled steel coils are inspected for chemical composition, mechanical properties, surface quality, and dimensional tolerance to meet GB/T 3091 / ASTM A53 requirements.
Uncoiling & Leveling
Steel coils are loaded onto the uncoiler and fed through a multi-roll leveler to flatten the strip and eliminate coil set before forming.
Strip End Shearing & Butt Welding
The head and tail of consecutive strips are sheared and joined by flash butt welding to ensure continuous production through the mill.
Edge Milling
Both edges of the strip are milled to precise width and prepared with the required edge profile for consistent welding quality.
Cold Roll Forming
The strip is progressively formed into a tubular shape through a series of fin-pass forming rolls arranged in a horizontal cage forming mill.
High Frequency Welding
The strip edges are heated by high-frequency induction and squeeze-welded together without filler metal to form a continuous longitudinal weld seam.
Weld Bead Removal
Internal and external weld beads (flash) are removed by carbide scarfing tools to achieve a smooth surface finish on the weld zone.
Sizing & Straightening
The pipe passes through sizing rolls to achieve accurate OD tolerance, then through a Turks-head straightener to ensure straightness ≤1 mm/m.
Cutting & End Facing
The continuous pipe is cut to fixed lengths by a flying saw, then both ends are faced and chamfered for clean, burr-free ends.
Hydrostatic & NDT Testing
Every pipe undergoes hydrostatic pressure testing (≥5 MPa for 5 seconds) plus ultrasonic/eddy current inspection to detect weld defects and laminations.
Hot-Dip Galvanizing
Pipes are pickled, fluxed, and immersed in molten zinc at ~450°C to form a uniform zinc-iron alloy coating (≥300 g/m²) for superior corrosion resistance.
Final Inspection & Packaging
Final visual inspection, coating thickness measurement, marking per specifications, bundling with steel straps, and protective end capping before shipment.
Applications
Where our products deliver proven performance across industries worldwide.
Scaffolding & Structural Support
Hot-dip galvanized scaffolding tube is the global standard for construction access systems — the zinc layer survives rough daily handling, weather, and concrete contact for years.
✓ EN 39 / BS 1139, zinc ≥ 300 g/m²
Fencing, Gates & Greenhouses
Galvanized tube frames for perimeter fencing, gates, handrails, and commercial greenhouses resist rust through decades of outdoor exposure with zero maintenance.
✓ Indoor/outdoor dual protection
Electrical Conduit & Cable Trays
Galvanized conduit protects electrical wiring in buildings and industrial plants, with smooth ID for easy wire pulling and grounding capability.
✓ UL 6 / EN 61537 conduit
Water Supply & Fire Protection
Galvanized piping remains standard for fire sprinkler mains, standpipes, and non-potable water lines, with predictable corrosion allowances indoors.
✓ ASTM A53 / FM-approved options
Agricultural & Irrigation Structures
Irrigation booms, livestock enclosures, grain-drying frames, and dairy equipment use galvanized tube in wet, corrosive farm environments.
✓ Hot-dip after fabrication
Telecom Towers & Street Furniture
Light poles, signal masts, camera posts, and telecom towers use galvanized tube for 20+ year maintenance intervals in all climates.
✓ Double-dip options for heavy sections
Frequently Asked Questions
What is galvanized steel pipe?＋
Steel pipe with a bonded zinc coating — applied by hot-dip galvanizing (molten zinc bath) after fabrication, or by pre-galvanizing the strip before tube forming — protecting the steel by barrier and sacrificial action.
What standards does your galvanized pipe comply with?＋
ASTM A53, EN 10255/10240, BS 1387, GB/T 3091, with zinc coating weights from 230 to 600+ g/m² per specification.
Hot-dip galvanized vs pre-galvanized — which should I choose?＋
Hot-dip (after forming) coats the full ID and weld area — best for water lines and harsh exposure. Pre-galvanized has a uniform finish but leaves the weld bare — suited to indoor and light-duty uses.
What service life can I expect from galvanized pipe?＋
In most atmospheres, hot-dip galvanizing provides 25–50+ years to first maintenance depending on zinc thickness and environment severity (C2–C5 corrosion categories).
What size range is available?＋
OD 21.3 mm to 273 mm (½"–10"), wall 1.8–8 mm, in standard lengths of 6 m with threading and coupling options.
Can galvanized pipe be welded, and how should welds be treated?＋
Yes — zinc vaporizes at welding temperature; clean the joint and repair the weld area with cold galvanizing spray or zinc-rich paint to restore protection.
Is galvanized pipe suitable for potable water?＋
It has a long history in cold potable water, though many modern codes limit it by water chemistry. We also offer linings and alternatives for aggressive water supplies.
What is the minimum order quantity and lead time?＋
MOQ typically 20–50 tons per size; common sizes ship in 1–3 weeks. Contact us for a firm quotation.
How is zinc coating quality verified?＋
Coating weight (g/m²) by stripping or magnetic gauge, adhesion by bend/hammer test, and uniformity per EN ISO 1460 / ASTM A123 — certified per lot.
What documentation comes with my order?＋
EN 10204 3.1 mill certificates, zinc coating weight certificates, and dimensional reports; third-party inspection on request.
Ready to Order Galvanized Steel Pipes?
Get a competitive quote within 24 hours. Our team of galvanized steel pipe experts is ready to help you find the perfect solution for your project.
📧 [email protected] | 📱 +86 15602135951 | 💬 WhatsApp Available