Galvanized Square
Steel Tubing (SHS)
PRE-GALVANIZED & HOT-DIP GALVANIZED
The ultimate rust defense for outdoor structures. High-strength carbon steel protected by a durable zinc coating for 20+ years of life.
Choose Your Protection Level
Not all galvanized pipes are equal. Select the right process based on your environmental requirements.
Pre-Galvanized
Also called "Strip Galvanized"
- Surface Appearance Smooth, Shiny, Bright
- Weld Seam Zinc Sprayed (Repaired)
- Life Expectancy 5 - 10 Years
- Cost Lower ($)
Hot-Dip Galvanized
Post-Production Dipped (HDG)
- Surface Appearance Dull Grey, Rugged, Spangle
- Weld Seam Fully Coated (Dipped After Welding)
- Life Expectancy 25 - 50+ Years
- Cost Higher ($$)
Why Galvanized Steel Lasts
Zinc protects steel in two unique ways, providing a defense system that paint alone cannot match.
1. Barrier Protection
The zinc coating acts as an impermeable shield (like a raincoat), physically blocking moisture and oxygen from reaching the steel core.
2. Cathodic (Sacrificial) Protection
Even if the coating is scratched or cut, the surrounding zinc will corrode instead of the steel, "healing" the wound electrochemically.
Technical Specifications
| Parameter | Specification Details |
|---|---|
| Steel Grade | ASTM A500 Gr. A/B / Q235B / Q345B |
| Yield Strength | Min 228 MPa (33,000 psi) - 345 MPa |
| Pre-Galv Zinc | Z40 - Z275 (G30 - G90) Typically 40-120 g/m² |
| Hot-Dip Zinc | 300 g/m² - 600 g/m² (ASTM A123) |
| Standard Length | 6.0m (20ft) / 5.8m (19ft) / Custom |
| Weld Seam | High-Frequency ERW (Longitudinal) |
Built to Last in Any Environment
From backyard projects to industrial infrastructure, galvanized tubing delivers reliable performance.
Fencing & Gates
The most common application. Pre-galvanized tubes offer a smooth finish ideal for powder coating and residential use.
Residential & Commercial
Agriculture (Greenhouses)
High humidity and irrigation systems cause rapid rust on normal steel. Galvanized frames are essential for longevity.
High Humidity
Structural Construction
Heavy-duty Hot-Dip Galvanized (HDG) sections used for columns, beams, and carports where maintenance is impossible.
Heavy Load & Outdoor
Traffic & Signage
Road sign posts and guardrails must withstand rain, UV rays, and corrosive road salts in winter.
Corrosive Road SaltStock Dimensions (SHS)
Standard lengths: 6.0m and 12.0m. Custom cut-to-length service available.
Light & Medium Duty
Furniture / Fence| Size (mm) | Wall Thickness | Typical Use |
|---|---|---|
| 15 x 15 | 0.8mm - 1.5mm | Furniture |
| 20 x 20 | 1.0mm - 2.0mm | Railings |
| 40 x 40 | 1.2mm - 3.0mm | Fence Post |
| 50 x 50 | 1.5mm - 4.0mm | Frame Structure |
| 80 x 80 | 2.0mm - 5.0mm | Sign Posts |
Heavy Structural
Construction / Industrial| Size (mm) | Wall Thickness | Typical Use |
|---|---|---|
| 100 x 100 | 3.0mm - 8.0mm | Columns |
| 150 x 150 | 4.0mm - 10.0mm | Beams |
| 200 x 200 | 5.0mm - 12.0mm | Infrastructure |
| 300 x 300 | 6.0mm - 16.0mm | Heavy Duty |
| 400 x 400 | 8.0mm - 16.0mm | Mega Structures |
Need the full Weight & Size Chart?
Download our complete PDF catalog containing theoretical weights (kg/m), zinc coating details, and ASTM tolerances.
⬇ Download PDF CatalogReady-to-Assemble Services
Save time on the job site. We process tubes to your exact specifications before shipping.
Precision Cutting
Band saw cutting to exact lengths (±1mm tolerance). No waste on your site.
Hole Punching
Pre-punched holes for fence fasteners or bolts. Custom spacing available.
Bending
Mandrel bending for greenhouse arches or structural curves without damaging the zinc.
Export Packaging
Waterproof plastic wrapping and steel strapping to prevent damage during transit.
Chromate Passivation & Oiling
Stop "White Rust" before it starts. We treat all galvanized tubes with a passivation solution and light oil. This prevents the formation of white storage stain (zinc oxide) during humid ocean transport or storage.
Common Questions
Technical answers regarding welding, storage, and lifespan.
Can I weld galvanized steel tubing?
Yes, but proceed with caution. Welding galvanized steel produces toxic zinc oxide fumes ("metal fume fever"). You must grind off the zinc coating at the weld site before welding and ensure the workspace is extremely well-ventilated. After welding, apply zinc-rich cold galvanizing paint to the weld seam to restore rust protection.
What is "White Rust" and how do I prevent it?
White rust is a white, powdery deposit (zinc hydroxide) that forms when galvanized surfaces are wet and starved of oxygen (e.g., stacked tightly in rain). To prevent this, we passivate our tubes. You should always store bundles at an angle to allow water drainage and keep them in a dry, ventilated area.
Can I paint or powder coat galvanized steel?
Yes (Duplex System). Painting over galvanized steel extends its life by 1.5x - 2.5x. However, standard oil-based paints do not adhere well. You must use a "Self-Etching Primer" or ensure the surface is properly prepped (lightly sanded or swept blasted) before powder coating.
How long will it last outside?
It depends on the environment. In rural settings, hot-dip galvanized steel can last 50+ years. In urban/industrial areas, expect 20-25 years. In harsh marine environments (near the ocean), the lifespan is reduced, and heavier zinc coatings (600g/m²) are required.
Health & Safety Warning: Zinc Fumes
Always wear a NIOSH-approved respirator when welding or cutting galvanized steel. Proper ventilation is mandatory to avoid inhalation of zinc oxide fumes.