Galvanized Square Pipe & Tube
We supply square tube galvanized steel, also sold as GI square pipe or galvanised square tubing. Sizes run from 10×10 mm to 400×400 mm, wall 0.8–16 mm, pre-galvanized or hot-dip.
Sizes in mm or inch, from 1 inch to 2x2 and up to 16" square
Pre-galvanized 60–275 g/m², or hot-dip 300–600 g/m² after forming
Structural tube to ASTM A500 Gr. B / C, EN 10219 S235JRH / S355J2H and JIS G3444 STK400 / STK500, with mill certificates
Straight, square-cornered lengths of 5.8 m, 6 m, 12 m, 20 ft or 40 ft, or cut to length
Why Order Galvanized Square Tubing From Us
01
Corners and Sides That Stay True
We check side length, wall, corner radius and twist on each lot. Square stays square, so your frames fit without shimming.
02
Weld Seam Protected
On pre-galvanized tube, the inside weld bead is trimmed. The outside seam is zinc-sprayed in line. You get no rust line along the seam.
03
Clear Specifications and Bundle Labels
Tube is supplied to agreed sizes, walls, coatings and standards. Each bundle is labelled, so you can check it against your order on arrival.
04
Cut, Punched and Ready to Weld
We cut to length, punch holes and notch ends in house. Parts arrive ready for your welding line.
05
8–12 Working Days Lead Time
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). Special walls and hot-dip orders take 2–3 weeks, depending on the order.
Square Pipe Galvanized for Frames That Stay Outdoors
A galvanized square pipe gives you flat faces to weld, bolt and drill. It carries load well in both directions. That is why fabricators choose it over round pipe for frames, racks and gates.
The zinc coat lets the frame stand outdoors without paint. For dry sites and indoor use, pre-galvanized square tube is enough. For coastal sites, farms and solar fields, ask for hot-dip galvanized square tube. Its coat is several times thicker.
Galvanized Square Tube Range
Pre Galvanized Square Steel Pipe
Pre galvanized square tubing is formed from GI coil. It has a smooth, bright finish. Best for furniture, shelving, greenhouses and indoor frames.
Hot-Dip Galvanized Square Tube
Dipped after forming, coated inside and out. For fences, gates, solar mounts and coastal structures. See Hot-Dip Galvanized Steel Pipe & Tube.
Galvanized Box Tube for Structures
Heavy-wall box tube to ASTM A500, EN 10219 S355J2H or JIS G3444 STK500. For columns, trusses and trailers.
Small Galv Square Steel Tubing
Sizes from 10×10 to 40×40 mm in thin walls. For furniture, displays and light frames.
Rectangular Sections
Need one side longer than the other? See Galvanized Rectangular Pipe & Tube.
Specifications
| Item | Range |
|---|---|
| Size | 10×10 – 400×400 mm; 1/2″ – 16″ square |
| Wall | 0.8 – 16 mm (pre-galvanized 0.8 – 2.5 mm); 20 to 7 gauge for inch sizes |
| Steel | Q195–Q355B, EN 10219 S235JRH / S355J2H, JIS G3444 STK400 / STK500; ASTM A500 Gr. B / C |
| Coating | Pre-galvanized 60–275 g/m² (both sides); hot-dip 300–600 g/m²; electro-galvanized 5–20 µm |
| Length | 5.8 m / 6 m / 12 m; 20 ft / 21 ft / 40 ft; or cut to length (e.g. 24 ft) |
| Standards | EN 10219, JIS G3444; zinc to ISO 1461 / AS/NZS 4680; ASTM A500; EN 10305-5, GB/T 6728 |
| Ends | Plain, cut square; punched or notched on request |
How to Choose Galvanized Square Tubing
Square tube looks simple. Yet three details decide whether it works in your frame: the coating, the wall and the standard. Here is how to get each one right.
Pre-Galvanized or Hot-Dip?
Pre galvanized square steel pipe is made from coated coil. The tube mill cuts the strip and welds it, so the inside weld and cut ends have little zinc. The coat is thin: 60–275 g/m² in total for both sides, about 4–19 µm per side. It looks bright and even.
Hot-dip galvanized square tube is dipped after welding. Zinc covers inside, outside, the weld and the ends. The coat is 300–600 g/m², about 40–85 µm. The surface is duller and less uniform.
Our advice: indoors or under a roof, pre-galvanized is the better value. Outdoors near salt, soil or animals, pay for hot-dip. If you weld after galvanizing, plan to touch up with zinc-rich paint either way.
Wall Thickness and Gauge
Metric orders state the wall in mm. US orders often use gauge. 16 gauge is about 1.5 mm, 14 gauge about 1.9 mm and 11 gauge about 3.0 mm. Write the mm value next to the gauge, and we will both read it the same way.
Pre-galvanized tube is limited to thinner walls, usually up to 2.5 mm. If your design needs a heavier wall, you will get hot-dip square tube instead.
Structural Standards
For load-bearing frames, ask for a structural standard. ASTM A500 Grade B or C is common in the Americas. EN 10219 S235JRH or S355J2H is common in Europe and the Middle East. Both control strength, size tolerance and corner radius.
Furniture and display tube usually needs no structural standard. Then tolerance and surface matter more. Tell us what the tube is for, and we will suggest the right grade.
Square Pipe or Square Tube?
For galvanized square sections, “pipe” and “tube” mean the same product. GI square pipe in Asia is square tube in the US. Both are sized by outside dimensions and wall, not by NPS. We list them together as galvanized square pipe & tube.
Frequently Asked Questions
What sizes does 2x2 galvanized tubing come in?
2x2 galvanized tubing is 50.8×50.8 mm. Common walls are 16, 14 and 11 gauge, or 1.5 to 4.0 mm. The 50×50 mm metric size is close but not equal. Tell us which one your drawing uses before you order.
Do you supply 2.5x2.5 galvanized square tubing?
Yes. 2.5x2.5 inch square tube is 63.5×63.5 mm. We supply it in walls from 2.0 to 6.0 mm, pre-galvanized or hot-dip. It is common for gate posts and trailer frames.
Can galvanized square tube be welded?
Yes. Grind the zinc away near the joint and weld with good ventilation. Zinc fumes are harmful. After welding, coat the joint with zinc-rich paint. For large assemblies, weld black tube first and hot-dip the finished frame.
Is a 1 inch GI square pipe strong enough for furniture?
Yes, for most chairs, tables and shelves. Choose a 1.2 to 1.5 mm wall. Go to 2.0 mm if the frame carries heavy loads or long spans.
How much does galvanized square tube cost?
Price depends on size, wall, coating type and quantity. Hot-dip costs more than pre-galvanized. Send your size list, and we will quote within 2–4 working hours. Quotes are valid for 3 days.
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