Hot Dip Galvanized Rectangular Hollow Section Tubes
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Send your sizes and quantity on WhatsApp +971 56 227 5722 or through the quote request form, and you get a figure back with a lead time. Cut to length included, mill test certificates with the material, delivery to all seven emirates.
Hot dip galvanized rectangular hollow section, also called HDG RHS or galvanized rectangular tube, is rectangular steel tube dipped in molten zinc after it is made, so it is protected inside and out. It is used wherever a rectangular member has to span outdoors: fence rails, gate frames, purlins for shade structures, solar mounting rails and external platforms. Seen Steel supplies hot dip galvanized RHS from 50 x 25 mm up to 400 x 200 mm, delivered to all seven emirates.
Sizes and weights
Weights are black steel weights at 7.85 g/cm³, before galvanizing. Standard length is 6 m.
| Size (mm) | Wall thickness (mm) | Approx. black kg per metre |
|---|---|---|
| 50 x 25 | 2.0 / 3.0 | 2.23 / 3.25 |
| 60 x 40 | 2.0 / 3.0 | 3.01 / 4.43 |
| 80 x 40 | 2.0 / 3.0 / 4.0 | 3.64 / 5.37 / 7.03 |
| 100 x 50 | 3.0 / 4.0 / 5.0 | 6.78 / 8.92 / 10.99 |
| 120 x 60 | 3.0 / 4.0 / 5.0 | 8.20 / 10.80 / 13.34 |
| 150 x 50 | 4.0 / 5.0 | 12.06 / 14.91 |
| 150 x 100 | 5.0 / 6.0 | 18.84 / 22.42 |
| 200 x 100 | 5.0 / 6.0 / 8.0 | 22.77 / 27.13 / 35.67 |
| 250 x 150 | 6.0 / 8.0 | 36.55 / 48.23 |
| 300 x 200 | 8.0 / 10.0 | 60.79 / 75.36 |
| 400 x 200 | 10.0 / 12.0 | 91.06 / 108.52 |
For the formula and more sections, see the steel weight chart.
How much zinc: EN ISO 1461
Hot dip galvanizing to EN ISO 1461 sets a minimum average coating thickness by steel thickness. Because the tube is dipped, the zinc coats the inside as well as the outside.
| Steel thickness | Minimum mean coating | Approx. zinc per m² |
|---|---|---|
| Under 1.5 mm | 45 µm | 320 g/m² |
| 1.5 to 3 mm | 55 µm | 395 g/m² |
| 3 to 6 mm | 70 µm | 505 g/m² |
| Over 6 mm | 85 µm | 610 g/m² |
Zinc adds roughly 3 to 7 percent to the black steel weight, more on thin walled tube and less on heavy sections. Our guide to GI coating classes explains how this compares with pre-galvanized Z120 to Z275 material.
Hot dip galvanized or pre-galvanized tube
Two very different products are sold as galvanized tube in the UAE. Pre-galvanized (often called GI tube) is made from strip that was galvanized before the tube was formed, usually Z120 to Z275. The coating is thin, the weld seam and cut ends are bare, and the inside is often not protected. Hot dip galvanized tube is dipped in molten zinc after it is made, so the coating is several times thicker and covers the inside, the weld and every cut end. For external, coastal and structural work, hot dip galvanized is the one to specify.
Rectangular or square
Stood on its long edge, a rectangular tube is stiffer in bending than a square tube of the same weight, which makes it the efficient choice for rails, purlins and beams. For posts and columns, use galvanized square tube. For uncoated tube, see mild steel RHS.
Standards
- Tube: EN 10219 in S235JRH, S275J0H or S355J2H, or ASTM A500 Grade B or C
- Galvanizing: EN ISO 1461 or ASTM A123
Common applications
- Fence rails and gate frames
- Purlins and rafters for shade structures and carports
- Solar panel mounting rails
- External platforms, walkways and stair stringers
- Trailer and equipment frames exposed to weather
- Agricultural and marine structures
Cutting and delivery
We supply 6 m lengths or cut to your list. Deliveries go to workshops and sites across all seven emirates, including Al Quoz, Jebel Ali, Mussafah, Sajaa, Ajman Industrial and Al Hamra. Mill test certificates are supplied with the material.
Frequently asked questions
What is the weight of a 100 x 50 x 3 galvanized tube?
About 6.8 kg per metre in black steel, plus a few percent for the zinc.
Can galvanized RHS be welded?
Yes, with good ventilation, but the zinc burns off at the weld. Repair every weld with zinc rich paint.
Is hot dip galvanized better than pre-galvanized?
For outdoor and coastal use, yes. The coating is thicker and covers the inside, weld seam and cut ends.
Do you supply mill test certificates?
Yes, MTCs are issued with the material.
Send your galvanized rectangular tube requirement through the steel quote request form or on WhatsApp at +971 56 227 5722.