50×100×1.8mm Hot Dip Galvanized RHS Q235B Rectangular Steel Tube
50×100×1.8mm Hot Dip Galvanized RHS Q235B Rectangular Steel Tube
High quality galvanized rectangular steel tubes for construction, framework, fencing and industrial fabrication. Good corrosion resistance, uniform zinc coating, straight dimension & smooth surface. Available in multiple sizes and thicknesses. Mill test certificate EN 10204 3.1 supplied. Contact us for stock list, sizes and factory direct price.
- Mill Test Certificate Provided
- Strict Quality Inspection
- Custom Sizes Available
- On-Time Global Delivery
Sky Steel Group supplies hot-dip galvanized (HDG) and pre-galvanized rectangular steel tubes (Rectangular Hollow Sections / RHS) for commercial building framing, architectural curtain walls, modular container housing, agricultural greenhouses, and heavy equipment chassis. Available in dimensions from 10×20 mm to 400×600 mm with wall thicknesses from 0.6 mm to 20 mm, our galvanized rectangular tubes conform to ASTM A500, EN 10219, and JIS G3466 standards.
Forming, Welding & Structural Performance
Our galvanized rectangular hollow sections are produced via high-frequency ERW forming with controlled edge radius and uniform wall thickness. The rectangular profile provides higher resistance to bending along the major axis compared to square tubes of equal weight, making RHS the preferred choice for horizontal beams, purlins, wall girts, and cantilevered supports.
The protective zinc coating creates an electrochemical barrier that protects cut ends and weld zones from rust. The flat outer surfaces simplify mechanical fastening with self-tapping screws, bolted gussets, and welded mounting plates on fast-track construction projects.
Galvanized Rectangular Tube Specifications
| Item | Available Range |
|---|---|
| Product | Galvanized Rectangular Steel Tube / Rectangular Hollow Section (RHS) |
| Type | Hot-Dip Galvanized (HDG) / Pre-Galvanized (GI) |
| Standard | ASTM A500 / EN 10219 / EN 10210 / JIS G3466 / GB/T 6728 / AS/NZS 1163 |
| Material Grade | Q195, Q235B, Q355B / S235JRH, S275J0H, S355J2H / ASTM A500 Gr. B/C / STKR400, STKR490 |
| Outer Dimensions | 10 × 20 mm – 400 × 600 mm / Custom Aspect Ratios |
| Wall Thickness | 0.6 mm – 20.0 mm / Strict ±5% to ±8% Tolerance |
| Length | 5.8 m, 6.0 m, 11.8 m, 12.0 m / Precision Cut-to-Length (±2 mm) |
| Zinc Coating Mass | Pre-Galvanized: 40–120 g/m²; Hot-Dip Galvanized: 200–550 g/m² (up to 80 µm) |
| Surface Treatment | Hot-Dip Galvanized / Lightly Oiled / Passivated (Chromated) / Anti-fingerprint |
| End Processing | Clean Square Cut / Deburred / Bevelled / Threaded / Pre-punched Holes |
| Secondary Processing | Laser Tube Cutting / Miter Cutting / Bending / Punching / Drilling / Flange Welding |
| Application | Building Columns & Beams / Curtain Walls / Greenhouse Frames / Solar Brackets / Modular Housing / Machinery |
| Certificate | EN 10204 3.1 Mill Test Certificate (MTC) / CE / ISO 9001 / SGS Inspection |
| Packing | Hexagonal Bundles with High-Tensile Steel Straps / Protective Corner Shields / Seaworthy Sling Protection |
| Customization | Custom Cross-Section Dimensions / Heavy Wall Thickness / Fixed Length / Pre-drilled Holes |
Need a Price for Galvanized Rectangular Tube?
Send us your required dimensions (OD × WT), length, zinc coating weight, steel grade, and quantity for a direct factory quote.
Where Are Galvanized Rectangular Tubes Used?
Galvanized rectangular steel tubes combine directional flexural strength, clean geometry, and long-term corrosion resistance. They are widely applied across structural engineering, pre-engineered buildings, agricultural greenhouses, modular homes, and marine export projects.
Precision Dimensions, Clean Ends & Diverse Cross-Sections
Manufactured with tight dimensional tolerances (±0.2 mm) and smooth deburred ends across popular sizes from 20×40 mm to 200×400 mm. The uniform zinc spangle and metallurgical bonding provide complete coverage on both inner and outer surfaces, preventing internal rust formation in enclosed hollow sections.
Modular Frameworks & Industrial Equipment Enclosures
Welded into heavy-duty modular cages, machinery skid bases, and outdoor utility enclosures. Hot-dip galvanizing protects welded joints against sand abrasion, high humidity, and direct solar exposure in harsh outdoor and desert construction environments.
Multi-Story Steel Structures, Columns & Load-Bearing Beams
Galvanized rectangular hollow sections serve as primary horizontal beams, floor joists, and vertical framework in multi-story industrial buildings and commercial warehouses. The strong major axis moment of inertia handles high bending loads while reducing total structural steel tonnage.
Prefabricated Modular Buildings, Container Homes & Sheds
Widely used as structural perimeter frames and roof trusses in modular housing, portable office cabins, and temporary work sheds. Their flat profile makes panel cladding, drywall fastening, and window/door frame installation straightforward and fast.
Agricultural Greenhouses & Solar Mounting Structures
Engineered for multi-span agricultural greenhouses, ground-mount solar racking, and carports. The zinc layer withstands constant moisture, fertilizer vapors, and soil contact, ensuring 20+ years of maintenance-free service without repainting.
Port Logistics, Seaworthy Packaging & Container Export
All export shipments are bundled in rigid square/rectangular packages using high-tensile steel straps, protective corner guards, and dedicated lifting slings for crane unloading. Packed specifically for 20GP (5.8m) and 40HQ (11.8m) container space maximization and zero transit damage.
Frequently Asked Questions About 50×100×1.8mm Hot Dip Galvanized RHS Q235B Rectangular Steel Tube
1. What is the structural advantage of rectangular tubes over square tubes?
Rectangular tubes feature an unequal cross-section with a distinct major (strong) axis and minor (weak) axis. When installed as horizontal beams, purlins, or cantilevers with the longer side oriented vertically, rectangular tubes provide significantly higher flexural strength and moment of inertia than square tubes of the same weight, reducing overall material consumption in building frameworks.
2. What is the difference between Hot-Dip Galvanized (HDG) and Pre-Galvanized rectangular tube?
The key differences are zinc coating thickness and service environment:
• Pre-Galvanized (GI) Tube: Produced from continuous galvanized coil with an inline zinc re-spray over the weld seam. Zinc weight is 40–120 g/m² (5–15 µm). Best suited for indoor structures, greenhouse arches, furniture, and light architectural framing.
• Hot-Dip Galvanized (HDG) Tube: Black steel hollow sections immersed in molten zinc bath at ~450°C. Zinc coating reaches 200–550 g/m² (30–80 µm) inside and out, delivering 25–50+ years of corrosion resistance for harsh outdoor, coastal, and industrial environments.
3. What sizes, wall thicknesses, and lengths are available?
We supply rectangular dimensions from 10 × 20 mm up to 400 × 600 mm with wall thicknesses from 0.6 mm to 20.0 mm. Standard export lengths are 5.8 m (optimized for 20ft containers) and 6.0 m / 11.8 m / 12.0 m (optimized for 40ft/40HQ containers), with custom precision cut-to-length services available (±2 mm tolerance).
4. Which steel grades and manufacturing standards do you offer?
We supply according to all major international structural standards:
• ASTM Standard: ASTM A500 Grade A, Grade B (min yield 315 MPa), and Grade C (min yield 345 MPa).
• EN Standard: EN 10219 and EN 10210 in S235JRH, S275J0H, and high-strength S355J2H.
• JIS Standard: JIS G3466 STKR400 and STKR490.
• GB Standard: GB/T 6728 Q195, Q235B, and Q355B.
5. Can galvanized rectangular tubes be welded, drilled, and miter-cut?
Yes. Our rectangular tubes support MIG/MAG welding, CNC hole drilling, punching, laser profile cutting, and 45° miter cutting for framing corners. Grinding off 20–30 mm of surface zinc at the weld point ensures optimal weld penetration; applying zinc-rich cold galvanizing compound after welding restores full cathodic protection.
6. How are rectangular tubes bundled and packed for international sea freight?
Tubes are packed into neat rectangular bundles strapped tightly with high-tensile steel bands (minimum 4–6 bands per bundle) and equipped with heavy-duty lifting slings for safe container unloading. Ends are deburred and can be fitted with protective caps. Wooden dunnage is placed between bundles inside containers to prevent transit friction and moisture trapping.
